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Shimano GRX – Gravel Bike Tech

A new series of technical articles

We get a lot of tech questions, especially about gravel specs. We love answering them but often think more people probably have the same questions. So here it is, everything you've always wanted to know about gravel tech, but were afraid to ask.

Text by Gerard Vroomen - 03 September 2019

The goal of this series is not to give in-depth reviews of products, but rather to highlight the few things that really matter and to solve a technical problem you may have with getting these part to do what you want.

Because let’s face it, gravel riding and racing is so individual, so dependent on where you ride, how you ride, how fast you ride and the skills you have, that the “standard setup” may not always work for you. And then you start to tinker, but you don’t want to end up with problems out in the field. So let’s start with the newest gravel groupset, Shimano GRX.

(Shimano claims “first gravel groupset”, but that’s more marketing speak and playing with the definition of words than that it reflects reality. After all, SRAM’s Force1 and subsequent groupsets are great gravel groupsets too)

A small preview of things to come appeared last year, when Shimano introduced Ultegra RX, a few gravel components that you could combine with regular Ultegra parts. But it lacked the wide range cassettes and 1x options to really be a serious alternative in this SRAM-dominated gravel market.

This year, Shimano is serious. GRX is a groupset designed from the ground up for gravel, with proper 1x and 2x options, wide range cassettes and some clever features. I won’t review each piece in detail, but pick out the things that are interesting and really matter:

The range: The new GRX range includes 1×11, 2×11 and 2×10. And within those, they also have a few different versions. This can make it confusing. In general the 10-speed bikes are sort of Tiagra level, the 11-speed bikes are more Ultegra level.

Shift/brake levers: These are awesome. Of course ergonomics are subjective, but a lot of people will love how these levers feel on the hoods. And Shimano has also changed the angle of the levers and the pivot point to make it much easier to brake from the hood position.

The mechanical shift/brake lever ergonomics on the hoods and while braking from the hoods are fantastic.

As you can see above, the mechanical and Di2 versions are different. I prefer the mechanical shape, it feels more natural in your hand. The difference over regular Shimano road shifters is remarkable; this is really a major step forward. And there is no reason to restrict this to gravel, you can put them on your dedicated road bike too if you like them.

1x gearing: TheRX-812 rear derailleur (RX-817 for Di2) is specifically for 1x and can handle up to 42T for the biggest cog. You can run Shimano 11-42 cassettes, or 11-40 for those who want a bit tighter range . You can even run a SRAM 10-42 cassette. That is not endorsed by Shimano but it works flawlessly in our lab and outside.

Combining the GRX RX-812/RX-817 rear derailleur with a SRAM 10-42 cassette? Shimano says no, I say go.

2x gearing: Quick rear derailleur basics, every derailleur has a maximum cog size it can handle AND a capacity. The capacity is the total numbers of teeth (really of chain links) it can “store” in its zig-zag shape. And for 2x, it needs be able to store both the tooth-delta of the cassette AND the delta between the front rings.

For the 1x rear derailleurs mentioned before, the capacity is 31T, which is already used up by just an 11-42 cassette. You can go a little further (which is why the 10-42T cassette also works), but it cannot handle another 16 links that you gain or lose when you shift between the front rings.

Bottomline, for 2x you need the RX-810 derailleur (RX-815 for Di2), with a larger 40T capacity (yeah!) but a smaller max cog size of 34T (boohoo!)

This means the biggest cassette you can run with this setup is 11-34. On the positive side, Shimano’s cranks come with very small inner rings (30T or 31T) so that your smallest gear can still be pretty small (30×34).

But it may come at a cost. On gravel bikes with dropped chainstays (which means pretty much every gravel bike, since they all copied the OPEN UP and 3T Exploro that pioneered it), a 30T inner ring puts the chain very close to the chainstay. So you need to be very careful in the setup to make sure that the chain length and chain tension keep the chain from swinging into it.

Another way around that is to ignore the 11-34T max cassette size Shimano recommends and install an 11-36. This works on most bikes without a problem. I just can’t guarantee it as it depends a bit on the geometry of your bike. But it certainly works on an Exploro and on other bikes, you can always try with the cheapest 11-36T cassette you can find.

Going beyond the Shimano gear range recommendation for 2x? Shimano says no, I say …. probably – a little. And I’d rather go with a bigger cassette than with smaller chainrings

The sub-brake lever: This is a nice touch, the sub-brake lever you can put close to the stem. I’d personally never use them, as I ride almost always on the hoods and not on the straight section of the bars. But if you do or are into cyclocross, this may be a selling point for you.

Mechanical vs. Di2: GRX comes in mechanical and Di2 versions. The options I described above for 1×11 and 2×11 exist in mechanical and Di2, the 1×10 is only mechanical. Di2 1×11 looks a bit silly, because there is no left brake lever without shift lever.

So you have a lame shift lever sitting on the left, unless you re-program it for a different function. Still doesn’t make it very useful, but you can program it to shift the rear derailleur with your left hand while you eat a banana with your right hand.

More problematic for me is that while for mechanical groups, 1×11 is the standard, for electronic you can get 1×12 from SRAM with a Force/Eagle combination. That’s a bit more expensive, but it’s nice to have that extra gear if you’re going to spend good money anyway.

1x mechanical GRX is great, 1x Di2 a bit pointless. For 2x, both mechanical and Di2 are nice (but of course 2x is a rapidly dwindling market for gravel).

So how about the Di2 in 2×11 setup? There the left lever obviously has a real function, and the one missing cog compared to SRAM Force 2×12 is not that big a deal (both are more gears than you need). And in 2x, Shimano actually has SRAM beat on useful range. SRAM’s smallest gear option is 33x33T if  you combine their 10-33T cassette with their 46/33T crank. Shimano’s smallest gear option is 30x34T, which is more appropriate for really touch gravel sections. As mentioned before, the big caveat is if the 30T chainring will clear your frame.

Final thoughts
I hope the above is useful for you, if you have any questions, additions or suggestions for future topics, feel free to post them below. More things to read?

  • Interested in a gravel bike with Shimano GRX, then check out this Exploro.
  • More of a SRAM rider? Then maybe the Exploro Pro Rival and Exploro Team Force  at a similar price points could be of interest. Or read my thoughts on hacking SRAM Force/Eagle AXS for gravel bikes.
  • Looking to hack your drivetrain to achieve  the most extreme gears? Read part 1 here.
  • What tires should go with that bike? If you want one set of tires for everything, read this. If you plan to have separate road and gravel wheelset, check out this article.
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242 responses to “Shimano GRX – Gravel Bike Tech”

  1. R

    Radovan says:

    24 August 2022

    I have an idea to mix RD-RX817 (11-42) and FC-RX810-2 (48-31). I know, that I go past the “31 limit”. But with Shimano synchronized shifting the combination “big big – small small” would never happen – so the real chain path lenght diferrence would be far below 31. What do you think about that?

    Reply
    1. Gerard Vroomen says:

      24 August 2022

      I know some people who have experimented with setups like that but we haven’t tried it ourselves. So i can’t really comment on it.

      Reply
    2. R

      R Wright says:

      24 October 2022

      Radovan – I can confirm that a RD-RX817 (11-42) and FC-RX810-2 (48-31) combination does work. It did require a new chain and indexing at the shop, but works really well and is an excellent mix. Doing a new build now and am going to try the combo with a 10-42.

      Reply
  2. F

    Frank says:

    21 August 2022

    As soon as i’m doing Triathlon, Looking for a road set for my specialized diverge.
    Any bigger crankcase suggested that fits
    Without many changes?
    Thanks in advance.

    Reply
  3. C

    CJ says:

    25 February 2022

    Hi Gerard, But I guess a 10-46T cassette would be a little over the top? Thx, Chris

    Gerard Vroomen says:
    01 December 2020

    You can get smaller chainrings from non-Shimano suppliers like Wolftooth, also for GRX cranks. You can also experiment with the 11-46T cassette, many people report that also works for them.

    Reply
    1. Gerard Vroomen says:

      04 March 2022

      A 10-46T in 11-speed? I am not sure who makes that.

      Reply
      1. C

        CJ says:

        07 March 2022

        Ingrid Bikes. I like it, although it’s quite espensive.

        Reply
        1. Gerard Vroomen says:

          07 March 2022

          Maybe check with Ingrid then, they may have tried it with a GRX RD. I’d say no chance with the 810 or 815 RDs, but maybe with the 812 or 817 models.

          Reply
          1. C

            CJ says:

            08 March 2022

            Thanks, Gerard! They say: „It works, but better wih the goat-link by wolftooth… because of the 10T
            sprocket. That derailleur does not support properly the 46. And if you open a lot when you are in 10t it engages very few teeths.“ I guess I leave it unchanged with 38 and 10-42. Cheers, CJ

            Reply
        2. F

          Fabrice says:

          07 August 2022

          I have tu use a freehub XD or XDr for a 10-42 cassette with a 1x GRX ?
          Thank you.

          Reply
  4. F

    Fowaz says:

    23 February 2022

    Quick question about the RD design…what mechanical part dictates the cog capacity of the RD….in other words….if I visually look at an 810 and 812 RD …..how would I be able to differentiate which one has more capacity?…..I always though that the 812 having a longer cage will have more cog capacity than the 810…but this article suggests other wise.

    Other question is if I replace my 810 case with an 812 cage will that give me more capacity in a 2X?

    Thanks,

    F

    Reply
    1. Gerard Vroomen says:

      24 February 2022

      The longer cage does help to collect more chain but it is also needed to reach the bigger cog diameter. And the capacity to “hold more chain” also depends on the complete S of the chain in the derailleur, not only the cage, and in particularly on the angles over which those two can move.

      Reply
  5. A

    Andy says:

    04 February 2022

    Hey there, Chain sizing question – I am building a Specialized Diverge with GRX 400 (10 speed) Front and Rear Mechs with RX600 2x cranks. The GRX dealer manual says to add 4,5 or 6 links depending on the plate match up.
    Why would I add 6 links? The manual says If you ae concerned about turbulence in the drive train add 6 links… Not sure what that means…

    Does anyone have experience with sizing a chain for GRX on 2x set up?

    Thanks

    Andy

    Reply
    1. Gerard Vroomen says:

      04 February 2022

      I’m not sure what that means either, I’ve never been concerned about turbulence other than in an airplane. I’m not sure what setup would be the best for your bike as it will have a different geometry to ours (different angle between chainstay and seattube so the cage won’t be in the same position.

      Reply
  6. p

    paul says:

    13 January 2022

    HI, for a gravelbike I want the setup Shimano GRX RD-RX812 1×11 combined with SRAM XG-1150 (10-42) which chain fits best with this setup? Please send brand and type.
    Thanks a lot

    Reply
    1. Gerard Vroomen says:

      13 January 2022

      any normal SRAM or Shimano 11-sp chain will work for that. It seems that the SRAM chain is a little quieter with that setup but both work flawlessly.

      Reply
      1. R

        Rey says:

        31 July 2022

        114 links will do? Im planning for kmc dlc red black chain? Thanks

        Reply
        1. Gerard Vroomen says:

          31 July 2022

          Depends on the bike model, chainring size, cassette size, etc. Best to get it a bit long and then do the proper sizing as indicated.

          Reply
  7. t

    tangofoxy says:

    03 January 2022

    Bit of a brainfart on the build, but I’ve running the 812 RD as 2x with an 11-40 SLX and 48/31 crank for 6,300 km with no real issues. I haven’t even adjusted the RD once. I’ve had a few dropped chains but mainly when it’s super dusty/dried out shifting from 31 to 48 and the rider was a tired moron. This was a complete build mistake that I only realized recently having bought a spare 810 RD and going, “huh,” but it’s worked fine for me. Given all the real world experience pushing cassette sprocket sizes, I think these GRX RDs are super engineered and very conservatively specc’d. In short, if anyone reads this later, just go for it.

    Reply
    1. Gerard Vroomen says:

      10 January 2022

      Yes, the GRX specs are very conservative (depending a bit on the frame it’s paired with). Also the 810 allows for much more than the rate 34T cog size.

      Reply
  8. Gaso-Us says:

    27 September 2021

    I have Ultegra 50/34T crankset with the RD-R8000 GS, so I would like to use on the rear SLX CS-M7000 11/42T. Is that possible, or I should go with 48/32T or maybe 48/31T, thanks

    Reply
  9. S

    Simon says:

    27 August 2021

    Just wanted to confirm that after some testing on my bike, my grx400 rd worksjust fine with a 10speed 11-42t cassette with some minor b tension screw adjustment, matched with a 1x crankset in 40t.

    I then upgraded my grx400 levers to 11 speed grx600 along with a new 11spd 11-42t cassette. My original grx400 rd still works fine on the new 11 speed setup, as it has the same cable pull ratios as the 800 series units.

    Reply
  10. P

    Pawel says:

    08 July 2021

    Great blog!

    I have ultegra 11 disk shifters, GRX 400 cranks, GRX 400 FD and RD
    I have access to XD 10-42 and shimano 11-40 cassette both with roadlink DM both option have poor shifting performance with this set up

    I would love to increase the front chainring for better speed 50T and retain the 30T small ring
    With what size cluster would you recommend

    Reply
  11. S

    Shaun says:

    25 May 2021

    My new 3T exploro Max GRX came with a press g
    Fit BB, not the threaded as advertised. Was there a spec change?

    Reply
  12. A

    Adam says:

    18 May 2021

    Hi Gerard!

    My bike came with the mechanical GRX 2X. 11-34t and 30/46 chainrings. (Cannondale Topstone Carbon 5, for reference.) I’ve found the low end to be pretty limiting here in CO and definitely would like more range, i.e. an 11-42t cassette. What rear derailleur and chain would be compatible?

    Alternatively, I could go 1X but this would be a much more expensive option as it seems I would need to replace a lot more parts and I don’t understand gearing well enough to know what combination of chainring/cassette would keep my high end while giving me more low end.

    This bike is everything from my roadie to hardtail. I do tarmac, gravel, and single track. So, I get on the highest gears occasionally on long moderate paved declines and I’m in my lowest gear ALL the time when climbing some of this stuff. Ha! (And forced to hike-a-bike.)

    Your advice on drivetrain compatibility would be appreciated beyond words. Thank you!

    Reply
    1. D

      Doug says:

      18 May 2021

      Gerard – ditto to Adam’s question. Living here in Idaho the GRX 810 2X. 11-34t and 30/46t rings (2021 Cutthroat C GRX 810) will be a challenge when fully loaded w/ grandpa leg power. Both front and rear derailleurs are GRX 810. Would be a happy camper w/ 11-40 and if god is listening 11-42 would be top-shelf.

      But where are my manners, great blog that I too stumbled upon and now have this website bookmarked for good and passing along to others in same boat.

      Thanks –

      Doug

      Reply
  13. P

    Prinsen Nico says:

    29 April 2021

    Hello, I have a GRX 815 drivetrain and looking for replacement for my front chainrings. My problem is that I canot find the original set up 48/31t any where in stock. So I wonder if it’s posible to fit other brands on my crank? It’s 110BCD 110/80, but some mechanics told me that only the original fit on the GRX crank? Is this true? I don’t mind going for a 50t if that still works with a 31t inner chainring.

    Reply
    1. Gerard Vroomen says:

      29 April 2021

      It’s not just the BCD but also the bolt pattern you have to be careful with nowadays. A quick search didn’t render much for me, it seems the outer ring from Rotor could maybe work, but no inner ring. So I am not sure. And i doubt that 50-31 will be very crisp.

      Reply
      1. P

        Prinsen Nico says:

        29 April 2021

        TY for the quick reply, I contacted ROTOR and askt if they have anything in there repertoir that would fit.
        Ty for the tip!!!

        Reply
  14. A

    Alex says:

    15 April 2021

    I’ve come to this post accidentally, but it’s a nice post.
    It is a serious global shortage of Shimano parts. I cannot find anywhere the RX-812 (1×11, max 42 teeth) rear derailleur. Nor will it come in stock soon.
    Do you know other rear derailleur that could do the same job? Sunrace or whatever?
    They need to have the same pulling with 1×11 road shifters for Shimano (I’m going to pair it, on a flat bar, with Shimano SL-RS700 11-speed Shift Lever ).

    Reply
    1. Gerard Vroomen says:

      15 April 2021

      Unofficially, the RX-810 will also shift up to 42T.

      Reply
  15. D

    Dan says:

    11 April 2021

    Great article. The options are certainly confusing. I am looking to change this Trek Checkpoint ALR 4 from a 2x to a 1x. It has a GRX RX400 derailleur and a 11-34 10 speed cassette. Would a 11-36 cassette work with a GRX RX600 40T crankset on this bike or would I have to upgrade the derailleur to an RX812 as well. Ideally I would like to increase the range for the cassette as much as possible in this potential 1x configuration. Thanks for the help. Dan

    Reply
    1. Gerard Vroomen says:

      11 April 2021

      Mixing 10-speed and 11-speed GRX won’t really work (unless you own a machine shop maybe). So if you want to go to 11-speed 10-36T, you need a new rear derailleur and shifter. And 10-36 is not much range for a 1x, it’s great for a gravel racer on moderate terrain but you’ll need more if you go beyond that.

      Reply
  16. F

    Fabian says:

    24 March 2021

    Hi Gerard,

    following your advice I am trying to assemble a Strada with Shimano GRX and a Sram Cassette and I found a pair of C35 Pro wheels in splendid condition, buuuuuut…. freehub out of stock.
    https://www.3t.bike/en/spare-parts/xd-r-driver-kit-616.html

    Any idea or advise on an alternative or availability (I figured that there are some, but all more expensive than a fresh pair of new training wheels).

    Best,

    Fabian

    Reply
  17. S

    Stephen Larkin says:

    23 March 2021

    I have Shimano R8000 50 34 front crankset, I am upgrading to Di2 but have a GRX RD 815 with 11 to 34 cassette, can I run this as the total capacity is 39 and the recommendation for GRX RD 815 is 38

    Reply
  18. P

    Paul clapham says:

    15 March 2021

    I have ashimano SLX 2×11 the front is 36/26 and rear 11 42 but the gearing is too low for my gravel bike i purchased a 50/34 front 105 but found that the sender shaft was not long enough . I think I need a 42 front and maybe 30 do they make some front gears to suit . Unsure of the PCD I think they are both different.

    Reply
  19. N

    NJ says:

    05 March 2021

    Hi Gerard,
    I’ve just order a Race grx 1x, If I want to upgrade the drivetrain to Dura Ace 9170 except the Crank, Because i will use the grx 46-30t. Can the DA’s FD handle the shifting? Because I understand that DA is for 50 or 52, instead of 46 of GRX.

    Reply
    1. Gerard Vroomen says:

      05 March 2021

      I would strongly advise against doing this. The FD curvature is the smallest problem, much more problematic is that the DuraAce rear derailleur doesn’t have a clutch, so you’ll constantly lose your chain. Furthermore, the GRX lever shape is much nicer, and the GRX brake calipers have Servo wave, they are basically a second generation road caliper while DuraAce is still first generation (and why pro cyclists still complain about the brake rotor rubbing).

      Reply
  20. f

    fabrizio piermaria says:

    10 February 2021

    hi to all, I have a grx 400 whit 46-30 and 11-34 cassette,if I will want to go 1x,can i change the derailleur eg. 812grx and stay whit grx400 shifters?

    Reply
    1. Gerard Vroomen says:

      10 February 2021

      When you say you have GRX 400, do you mean your shift/brake levers are from the 400 series? Because those would be 10-speed and the 812 would be 11-speed so that’s not compatible.

      Reply
  21. J

    John Shepard says:

    09 February 2021

    Hello everyone. Very happy to have discovered this blog! I recently purchased a Pinarello Gravel bike that is running Ultegra R8000 components with a 50/34 up front and an 11/32 cassette. A friend is offering me a great deal on a slightly used GRX Di2 groupset RX815 but it looks like the RD and FD have specifications for 11/34 max and 46-48 top gear teeth for the FD. I assume the RD will be fine but would the GRX FD (46-48 Max) get along with a Ultegra FC-R8000 50/34?

    I have been wanting to dip into Di2 for some time and I already have the GRX sub-brake levers installed on the bars so going full GRX is already in my game plan but I am wondering if I will have to also replace the Ultegra FC with a GRX Front Crank to make it all work.

    Thank you in advance and I apologies for my ignorance.

    John

    Reply
    1. Gerard Vroomen says:

      09 February 2021

      hi John, your first paragraph is not a great ice breaker! 🙂

      But seriously, the curvature of the GRX is geared towards a smaller ring but the 50T will be OK. The other things to check is if the FD mount on that frame is long enough that you can get the FD that high.

      BTW, that RD will definitely accept a bigger cassette as well, up to 11-42T even depending on the capacity needs of the crank, but definitely 11-36T is no problem and in many cases a nicer setup (that’s our standard GRX setup, with 11-36T instead of 11-34T).

      Reply
  22. P

    Pat Moore says:

    03 February 2021

    Greetings Gerard!

    I absolutely love my EXPLORO GRX and have put over ~ 5k miles ~ in 6months. The Grx groupset is great and I have really enjoyed riding this on road, gravel and light mtn bike trails. The only issue I have had is trying to figure out how to efficiently add a power meter to the bike… Will left side crank work (stages, 4iiii)? Any suggestions? Or tweaks?

    Thanks in advance!

    P moore

    Reply
    1. Gerard Vroomen says:

      09 February 2021

      Stages and 4iiii are challenging. Systems that add a pod on the inside of the crank arm don’t work that well for gravel, as that’s the same space that good gravel bikes use to push the chainstays into so that there is more tire clearance. Not a problem for road but tough for gravel.

      Aside from pedal based systems, you could look at ROTOR and Easton which have systems that are housed in the axle, so they avoid any pods.

      Reply
  23. S

    Shaun says:

    18 January 2021

    Hi Gerard,

    Wanting to build an Exploro, with GRX 1x for a 210 mile gravel race in June, but the 812 rear derailleur wont be in stock for 3-6 months I am told. I have all the other parts to build up a frame, can I just buy an 810 and change the cage? I can get a cage assembly, and looks like you have frames in my size… To my untrained eye the 810 and 812 look identical except the cage length..

    Reply
    1. Gerard Vroomen says:

      18 January 2021

      Hi Shaun, I’m not 100% sure if that’s the only difference. I would think the link one up from the cage would also have a slight difference but I don’t have both derailleurs handy here at home to check.

      Reply
      1. S

        Shaun says:

        18 January 2021

        You’re probably right… Thank you for the reply.. I’ll build one someday!!

        Reply
        1. F

          Filip says:

          08 August 2021

          Despite the similar looks, the 810 and 812 rear mechs are very different when inspected up close. The 812 cage does not fit on the 810 body. I recently tried it myself and failed miserably.
          And yes, the 810 will shift a 11-42 cassette but it does so a tad reluctantly and operates at the outer limit of the B adjustment screw. On my rig (Reilly Gradient) it also frequently goes out of alignment.
          Up until recently I was unknowingly running exactly this setup but I bashed my mech in and needed a new cage. I ordered the 812 cage and only after trying to fit it did I realise that I was actually running the 810 mech.

          Reply
  24. C

    Colin says:

    12 January 2021

    Hi Gerard,
    Hope you had a fantastic Christmas and New Year!
    I’ve got GRX810 RD with SRAM 11-36 rear cassette. I was hoping to use 50-34 front rings. In your experience will that combo work well/OK/poorly? I also noted that there will be about 2-2.5mm clearance to the chain stay from the big ring. Do you see that being a problem for sandy/loamy gravel and single track rides?
    Thanks in Advance!

    Reply
    1. C

      Colin says:

      12 January 2021

      HI Gerard, Just re-read through the comments and noticed your 8th Jan 2020 reply to Eriks post. 1st part of my question answered with “works flawlessly”. I’ll read the comments more carefully next time…

      Reply
    2. Gerard Vroomen says:

      12 January 2021

      We recommend 2mm minimum clearance between chainring and frame. Not much muck building up there, at least not for very long 🙂

      Reply
      1. c

        colin says:

        13 January 2021

        Awesome news!
        Thanks for your prompt reply Gerard!

        Reply
  25. M

    Morvan Parize says:

    05 January 2021

    Amusingly enough, going by the Shimano site, the GRX400 rear derailleur has a 41T capacity. Which means that while the GRX800 can’t go up to the 11-36 cassette, the GRX400 can.

    Reply
    1. Gerard Vroomen says:

      12 January 2021

      GRX 800 can also go to 11-36T, in fact that’s what we spec standard on the 2x GRX as the 11-36T cassette is much nicer than the 11-34, it gives you that little bit extra range. You can even run an 10-42T if you use the 810/815 rear derailleur.

      Reply
  26. S

    Stuart says:

    29 November 2020

    Hi,
    I’ve got a new gravel bike with the new GRX 600 (with 810 derailleur) groupset. I am running 1×11 40T chainring and 11 42 casette.
    Unloaded I am finding climbing relatively hard work on offroad hills.
    Now I am anxious about loading it up for bikepacking adventures and looking to get better ratios for climbing.
    As far as I know I can’t get lower than 40T chainring. Are there any options for me?

    Reply
    1. Gerard Vroomen says:

      01 December 2020

      You can get smaller chainrings from non-Shimano suppliers like Wolftooth, also for GRX cranks. You can also experiment with the 11-46T cassette, many people report that also works for them.

      Reply
  27. C

    Claus says:

    24 November 2020

    Hi.
    Im a heavy rider (135 kg, 186 cm) looking at the Expolore series, but cant really decided between Race and Max. I’ll use a MTB when really off-road, so the gravel will be used primarly on road and light gravel.
    Q1: Any advice? Can the frme handle me?
    Q2: Any recommendation or do you have wheelsets designed for riders of my weight?
    Q3: Possible to mix some Shimano XT components into the supply? Or have to rectrofit? Im thinking about the break caliber BR-M8120 due to the 4 piston and thereby more breaking power.
    Q4: You seams to have matched up colors with choice of groupset brand – can this be changed?
    Thanks in advance, Claus

    Reply
    1. Gerard Vroomen says:

      24 November 2020

      Hi Claus, given the extreme use case of Exploro frames, we recommend a maximum rider weight of 110kg.

      Reply
  28. J

    Jeff says:

    26 October 2020

    Gerard – with GRX RD RX817, the Wolf Tooth 38T chainring, and the SRAM 10×42 cassette – seems like best of all worlds, if all play nicely together. Any suggestion on the chain – Shimano or SRAM?

    Reply
    1. Gerard Vroomen says:

      26 October 2020

      Both would work but a SRAM chain is probably a little quieter for you.

      Reply
  29. O

    Oliver B. says:

    24 October 2020

    Hi. What components would you recommend to set up my new dream bike, which will be an Upper (40 or 45mm rubber). I plan to ride Santa Monica Mountains, so would like a great uphill ratio, but also a decent gear while riding the roads to the mountain. I think you like the GRX 2x chainring (48×31 or the 46-30?) and the SRAM 11-36T cassette. What chain?

    Any reasonable way to get an even more uphill friendly cassette? Thanks!

    Reply
    1. Gerard Vroomen says:

      24 October 2020

      Either chain works but I prefer the SRAM one in this setup. With the 810/815 rear derailleur you can also go bigger (it’s rated to 34T but there are people running an 11-42 or even 10-42 cassette, the latter requiring an xD(R) driver on your wheel.

      Reply
  30. N

    Nicola says:

    20 October 2020

    Forgot to mention, the front crankset is a Shimano GRX 600 with 40T

    Reply
  31. N

    Nicola says:

    20 October 2020

    Hi, will a SRAM XG-1199 (10-42) work with GRX 812 rear derailleur? If yes, could I keep using the HG601 chain?

    Reply
    1. Gerard Vroomen says:

      20 October 2020

      Yes that works. Normally the SRAM chain is a little quieter than the Shimano chain in that setup but both work.

      Reply
  32. j

    jorge says:

    15 October 2020

    Is it possible to mount 2×11 GRX setting , with 46/30 and 11-40t?

    Reply
    1. Gerard Vroomen says:

      20 October 2020

      Yes, ironically the best with the 810/815 rear derailleur.

      Reply
  33. R

    Robert Weiser says:

    13 October 2020

    Hello,
    Waiting for my Exploro race 2X to come in. OEM is 11-36 in back and 46 x 30 in the front. I live in S Florida where it is flat with pretty much no climbing. Can you check with the Shimano rep. to see if I can change the small chainring from a 30 to a 36 and drop the cassette from a 11-36 to a 11-30 GRX or to a 11-28 Ultegra cassette. I’m sure this would be helpful for other people living in the flatlands where over gearing is not needed. Thanks.

    Reply
    1. Gerard Vroomen says:

      20 October 2020

      You can definitely do that if you can find the ring (which could be a challenge with the GRX BCD). But since the group is still new, more chainrings appear regularly).

      Reply
  34. E

    Eric Pedersen says:

    02 October 2020

    FYI, you can not only go 11-36 on the 810, but easily an 11-40. Just spin down the B screw and don’t try to cross chain big to big. I am not the only one to do it, I’ve done about 100 miles on mine but others have a lot more time on it

    Reply
    1. J

      JULIAN MUÑOZ GONZALEZ says:

      14 December 2020

      buenas tardes puedo poner casette 11-40 con mi cambio trasero grx 810 y doble plato grx 810 31-48?

      Reply
      1. Gerard Vroomen says:

        15 December 2020

        Si, es posible.

        Reply
  35. G

    Graham says:

    22 September 2020

    Hi Gerard and everyone else,

    I would like to know whether it is possible to use the 46/30 chainrings from a FC-RX600-11 crankset (can be bought individually) and install them on a FC-RX810-2 crankset, i.e. get the lower gearing from the GRX 600 chainrings and the lighter and higher spec. of the GRX 800 cranks.

    I read somewhere that they should fit as the Bolt Circle Diameter (BCD) for both big and small chainrings is the same, but there may be an issue with the bolts being a different size.

    Presuming you can do the chainring swap described above, do you think it would it be possible to just replace the 31T chainring from the FC-RX810-2 crankset with the 30T chainring from the FC-RX600-11, and would the FD-RX810-F front derailleur still work. I ask because the front range will have increased by one tooth from 17T to 18T.

    If the front derailleur will work with the increased front range, could you use this 48/30 GRX 600 /800 hybrid crankset up front with a 11-36 SRAM cassette out back (which appears to be a widely accepted and compatible alternative to a Shimano 11-34 cassette).

    I look forward to hearing your thoughts on this potential option to significantly increase the gear ratio on offer from a Shimano GRX (mainly) drivetrain.

    Reply
    1. Gerard Vroomen says:

      22 September 2020

      Unfortunately, I don’t know if either of these modification would work.

      Reply
  36. E

    Emilio says:

    17 September 2020

    Hello Guys,
    Im using the Grx 812 1x, and im totally not satisfied.
    I was believing in shimano, but this time not. Gears too noisy, not precised and if u try to use the lowest speed, for example in high mountain, u feel that is not working good, forcing top much. Same when tou want to reach high speed, essentially u cant.

    Honestly id prefer a XTR, or Shimano 105.

    Reply
    1. Gerard Vroomen says:

      22 September 2020

      Hi Emilio, I’m not sure, I’ve not seen these issues on the GRX bikes I’ve ridden or from 3T customers. Maybe it’s a setup issue or something else. Hard to judge for me from a distance, best to check with your mechanic. As for the noise, we often combine the GRX derailleur with a SRAM cassette, that’s a quieter setup than with the Shimano cassette (don’t ask me why). So that might be an option for you.

      Reply
  37. A

    Anton says:

    23 August 2020

    Hi, Can I remove the cage and pulley of Shimano XT M8000 rear mech long cage and transfer that part to my Shimano GRX 810 Rear mech? I saw a video (https://youtu.be/7kUxmkuJWNg) and plan to follow the similar set-up to accomodate the 11-46 SLX cassete

    Reply
    1. Gerard Vroomen says:

      23 August 2020

      No idea, but a few things:
      – The RX810 is the medium cage GRX rear derailleur (for 2x), so that’s far short of what you need. The RX-812 is the long cage derailleur (for 1x). Some use the latter without any modifications with the 11-46T cassette. Can be a bit noisy but it works.

      Reply
  38. O

    Oleg says:

    13 August 2020

    Can you tell me the exact diameter in mm of the 40T gear (Shimano CS-M8000 11-40). I want to mount this cassette on my road bike with Ultegra 8000. Thanks in advance.

    Reply
    1. Gerard Vroomen says:

      23 August 2020

      Not really, not sure what you mean by exact, which part of the chainring do you think is leading? But you can calculate the nominal diameter yourself, any bike chain has a 1/2″ pitch, so 40T means a circumference of 20″. Divide by pi and you have your diameter.

      Reply
  39. Jean-Pierre says:

    27 July 2020

    Hello Gerard,
    I’ve installed the Shimano 14-40 cassette on my 1X1 Sram Force set. Unfortunately the long cage is not long enough and I had to mount the RoadLink (WoolfTool) but it’s not perfect…
    Do you think the GRX derailleur would work with my SRAM Hydro 11 shifter?
    Thank you!

    Reply
    1. Gerard Vroomen says:

      23 August 2020

      That won’t work, but you may be able to tweak your setup. I don’t think a road link is needed either. Check here: https://blog.3t.bike/2020/01/12405/gravel-bike-tech-gears-for-tough-climbs-part-1/

      Reply
  40. M

    Mark says:

    16 July 2020

    Hi Gerard, I have GRX on my 3T exploro. Im finding that I cant tighten the rear through axle enough. As soon as I tighten it, so too do the brakes and the wheel wont turn. The only way is to leave it “almost figure tight” and then the wheel rolls smoothly. Any suggestions ?

    Reply
    1. Gerard Vroomen says:

      16 July 2020

      That sounds like something in the rear hub. Best to directly contact our customer service with the bike ready, they can check exactly what wheel you have and give further advice. Probably something that the wheel maker can better answer but try our tech service first: https://company.3t.bike/contact-us/

      Reply
      1. m

        mark says:

        16 July 2020

        Thanks for the quick reply. The same applies for my 650b wheelset and the 700 wheelset. ( so unless a complete fluke, i doubt it would be the hub problem on both wheels)

        Reply
        1. Gerard Vroomen says:

          16 July 2020

          That’s beyond bizarre. But just contact the tech support, then you can also attach photos and everything so they can maybe see if there is something that’s not sitting right.

          Reply
  41. P

    Paul McCormack says:

    05 July 2020

    Hello Gerard,

    LBS tell me 42t chainring with 11-42t cassette wont work (GRX 8xx). Since both are available I’m very surprised they wont work together. I’m sure some people must be running the biggest cassette and chainring options together? If yes, are any modifications necessary?

    Cheers!

    Reply
    1. Gerard Vroomen says:

      16 July 2020

      Hi Paul, no idea why they would say that, I don’t see any problem. Assuming of course you have the 812/817 rear derailleur and not the 810/815 (although even with those it will sort of work).

      Reply
  42. Arno says:

    02 July 2020

    I do also have a question – hope you can help me, please:
    Can I pair SRAM Red 22 – 43/36t with a SRAM 10-42t Cassette (XG-1150)
    Regards

    Reply
    1. Gerard Vroomen says:

      16 July 2020

      Maybe, I’ll have a post coming up on 2x with wide range cassettes

      Reply
    2. Gerard Vroomen says:

      23 July 2020

      I don’t think there is any rear derailleur that can collect all that chain slack (i.e. none with a big enough capacity).

      Reply
  43. J

    Justin says:

    23 June 2020

    I have a Canyon Grail AL 7.0 that uses the GRX FD-RX810 and GRX FC-RX600. After having the bike for a while, I actually want to do more road rides, so I want to change my setup from a 46/30 to a compact 50/34 and shorter 165 cranks. Looks like the only setup I can get then is the Ultegra FC-R8000.

    Question is – would an Ultegra FC-R8000 work with my GRX FD? I know there’s the 2.5mm difference with the GRX series, but could that be adjusted to work? Or should I buy an Ultegra FD to match?

    Reply
    1. Gerard Vroomen says:

      24 June 2020

      Hi Justin, doesn’t Canyon have the answer for this question? I know part of the answer but the rest you need to take a look yourself as there are frame-specific issues. But here is what to do. For the derailleur to work it has to go 3.5mm (not 2.5mm) further inward on Ultegra than on GRX. So if your front derailleur is set up correctly now for GRX, simply remove the chain (at least take it off the chainring so it doesn’t block derailleur movement) and loosen the inner limit screw. See if you can actually move it inward by 3.5mm without getting to the and of the range for the derailleur AND without the cage hitting the frame. If that works, then I see no problem why the 50-34T crank wouldn’t work. Of course, the curvature of the cage is not absolutely perfect, but there is enough leeway there for it to work (in the end a front derailleur are just two dumb plates pushing against the chain, it’s not high tech. So if it can be positioned correctly laterally (as I described how to check), you’ll be fine.

      Reply
  44. M

    Matt says:

    10 June 2020

    HI All,

    I’m getting new bike in next 2 weeks Cube Cross Race SL 2020

    https://www.cube.eu/en/2020/bikes/road/cyclocross-gravel/cross-race/cube-cross-race-sl-bluegreynorange-2020/

    This bike is using REAR DERAILLEUR: Shimano GRX RD-RX812, Direct Mount, 11-Speed with CASSETTE: Shimano CS-M7000, 11-42T and CRANKSET: Shimano GRX FC-RX600, 40T. Then it looks like RD-RX812 can handle 42T cassette.

    I’m just wondering if decide to go and change the Crankset to this: FC-RX600-11, 2×11, 46-30T. I can still use that RD-RX812 on the back with new Crankset?

    Do you think it is gonna work or not?

    Thanks

    Reply
    1. O

      Oliver says:

      11 June 2020

      Hi Matt!

      This is basically identical to my question right below yours.

      The 11-42 cassette is not meant to be used with the 2×11 chainring, so Shimano’s official answer would be no, those are not compatible. The reason is because neither of the rear derailers have the capacity to take up the chain slack that would be produced by such a wide range of gears (30/11 being the shortest and 46/42 being the longest, there’s a 47 tooth difference, but the RX810 has a capacity of 40, while the RX812 only 31).

      Choosing the chain length carefully, you could theoretically set it up in such a way that you would only be missing small-small and large-large combinations, which we don’t normally use anyway, but this is not an ideal setup, and could potentially be dangerous, but at least inconvenient.

      The Shimano Deore XT series M8000-SGS mountain bike rear derailer is 11-speed, has a maximum total capacity of 47, and can handle a 42 tooth sprocket, so that ticks all the boxes. I would try that one if I really wanted to make it work. Whether they’re truly compatible, I’m sure the official answer is “no”.

      Reply
      1. M

        Matt says:

        11 June 2020

        Hi Oliver,

        Thanks for your quick answer. And it looks like to get this setup going I have to go with GRX RD-RX810 and it looks like this is will working OK with CASSETTE: 11-42T and Crankset: 2×11, 46-30T

        Please see link below that I found on line with that setup:

        https://bikepacking.com/gear/wide-range-grx-2×11/

        and

        https://www.instagram.com/p/B1U0AxMHtct/?utm_source=ig_web_copy_link

        It looks like RD-RX810 can handle CASSETTE: 11-42T and GRX Crankset: FC-RX600-11 – 2×11, 46-30T no problem 😉

        Like you mention above I would maybe only be missing small-small and large-large combinations that I don’t mind as I looking more for flexibility with speed if I need it and clime up the hill, in Dublin, Ireland it is easy to find both!

        Thanks

        Reply
      2. M

        Matt says:

        12 June 2020

        Hi Oliver,

        Thanks for your quick answer. And it looks like to get this setup going I have to go with GRX RD-RX810 and it looks like this is will working OK with CASSETTE: 11-42T and Crankset: 2×11, 46-30T

        I’m not sure if I can post link to different websites here, but please go and search Google for “THE IDEAL TOUR DIVIDE DRIVETRAIN? ULTRA-WIDE RANGE GRX 2×11”

        and

        https://www.instagram.com/p/B1U0AxMHtct/?utm_source=ig_web_copy_link

        It looks like RD-RX810 can handle CASSETTE: 11-42T and Crankset: 2×11, 46-30T no problem 😉 and my setup should be ok.

        Like you mention above I would maybe only be missing small-small and large-large combinations that I don’t mind as I looking more for flexibility with speed if I need it and clime up the hill, in Dublin, Ireland it is easy to find both!

        Thanks

        Reply
    2. Gerard Vroomen says:

      15 June 2020

      Using the 1x (812) rear derailleur for 2x will not work. Using the 2x (810) rear derailleur and going beyond the recommended max cog size, there are some options. More to come soon in the next gravel bike tech post.

      Reply
  45. O

    Oliver says:

    08 June 2020

    Would it be possible to use the 2X crank set with the 11-42 cassette for an even wider range of gears? I understand that it exceeds the capacity of the rear derailer, but what if I choose the length of the chain so that I will only be missing a few of the small-small and large-large combinations, but still have enough capacity to use the small chainring with the larger sprockets, or the large chainring with the smaller sprockets. Or just use a mountain rear derailer that has a bigger capacity?

    Reply
    1. Gerard Vroomen says:

      15 June 2020

      This answer would be the length of a full blog post. Luckily I am writing such a blog post right now. Hope to have it up in the next few weeks.

      Reply
  46. J

    Johan says:

    06 June 2020

    Hello Gerard, i will be doing some “serious” climbing next month. ( first time…… )
    Currently i am driving the GRX 810 1×11 42 crank with 10-42 Cassette.
    Which would be better…….changing to a 11-46 Cassette ) ( does that work ? ) or rather get a 36 or even 34 chainring in the front ( does that work ? )

    Thanks for some usefull infos for a “mountain-newbie” !!
    I do about 5k a year, most of it plain as a pizza thouhg……LOL

    Cheers, Johan

    Reply
    1. Gerard Vroomen says:

      07 June 2020

      Both work, sort of, but I prefer the smaller ring. You are probably looking for this article: https://blog.3t.bike/2020/01/12405/gravel-bike-tech-gears-for-tough-climbs-part-1/

      Reply
      1. J

        Johan says:

        09 June 2020

        THX for your help Gerard,

        okay, so i will just Change the ring and leave the 11-42 Cassette on.
        The smallest GRX ring in offer is from Wolftooth ( 38T ).
        Or can i just put a 36 XT/SLX ring on the GRX Group ( 810 )

        Reply
  47. P

    Phil says:

    02 June 2020

    So I have GRX 1×11 11-42t came on my bike, with Easton EA90 cranks and 38T chainring. It’s nice, goes just nicely low enough, but I thought I’d try swapping my shimano freehub with an XD driver and putting a lighter SRAM 10-42t for slightly wider gear range and a little more top end speed when on the tarmac. I find my SRAM XD/cassette sits about 2.5mm further out than the shimano though and after adjusting the derailleur to account it doesn’t seem so smooth down on the little teeth. As the chainline is further out at the back now relative to the front, it has a steeper chain-line on the little cogs where it seems fussiest. Got any experience of this? Is that normal the SRAM cassette is slightly further out, or is that my particular wheel/freehub combo? Obviously I don’t want to keep throwing too much money at it if it’s not gonna play nice, but since I’ve already spent money on a freehub/cassette, any way of making it smoother in the top couple of cogs would be good. I looked for Easton compatible chainrings with slightly reduced offset to bring the front out a couple of mm, but I’m not sure they’re a thing that one can buy based on a bit of googling. If it definitely works using SRAM 10-42 with GRX, including said further rear cassette offset, maybe I just need to fiddle more? I haven’t tried riding it with the SRAM, it just seems a bit rough there on a bike stand.

    Reply
    1. P

      Phil says:

      02 June 2020

      P.S. or maybe a spacer on the drive side of my BB to push the crank out which could do a similar thing, but then I’d haver to back the tensioner off and it may not go that far, and so I don’t know if that’s doable either.

      Reply
      1. P

        Phil says:

        02 June 2020

        Don’t worry, after more fiddling, less tired, in better light, the above still stood, but it seemed a little better on 3rd attempt. After a through chain degrease it was a little better on the stand but the resonant sound was still present. While pondering what I posted above and I hadn’t test ridden it, I found under load on the test ride it was absolutely fine though and seemed to shift great with no more noise than before. So now I can go faster on smooth tarmac and downhill and as a bonus it weighs a bit less than the original cassette too. Living the dream!!! 😀

        Reply
    2. Gerard Vroomen says:

      03 June 2020

      Just want to make sure you are not using the 1.8mm xD-R spacer if you’re putting the 10-42 onto the xD driver? That would throw it off. Other than that, the two cassettes shouldn’t align that differently really. That’s a bit surprising.

      Reply
  48. A

    Alan Taylor says:

    27 May 2020

    My father is getting a custom titanium gravel bike built that has Shimano GRX Di2 46-30/11-34. You you mix and match with eletronic shifting as with manual shifting? Down the line, if he wanted even smaller gears, could he put even smaller sub-compact cranks on a GRX electronic setup, for example 42-26 or 40-24? His frame clearance will give him a max tyre width of 40mm. I understand you can put different sized cranks on manual shifting setups, but not sure if there are additional constraints to mixing and matching on electronic shifting.

    Reply
    1. Gerard Vroomen says:

      28 May 2020

      Theoretically you could mix mechanical and electronic, but the levers are not the same shape so it might feel a bit weird to have a different hood shape on the left and right. With the smaller rings you suggest, the curvature of the front derailleur cage will fit to the chainring curve worse and worse as you shrink the rings, so shifting will degrade and at some point simply stop working.

      Also, you need to lower your front derailleur as the chainrings get smaller so at some point you run out of room on the slot from your front derailleur hanger. That’s why SRAM has that special WIDE front derailleur, it hangs farther below the attachment bolt so you can bolt it to a standard front derailleur mount and still have the cage hang lower.

      Reply
  49. T

    Tat says:

    08 May 2020

    I am not sure if this has been asked and answered yet but do you think it would be possible to use a GRX600 1 crankset with a GRX400 rear derailleur?

    Reply
    1. Gerard Vroomen says:

      14 May 2020

      Haven’t tried but I don’t see a glaring problem with that. No guarantees though.

      Reply
  50. G

    Greg Chen says:

    29 April 2020

    Hi Gerard,
    Have you tested whether the Shimano GRX RX 812 rear derailleur can be put on a 2×11 setup (instead of the 1×11)?

    I have a Blue Prosecco 2018 gravel bike with a standard Shimano 105 groupset Front Derailleur: 105 5800; Rear Derailleur: 105 5800 ; Chainrings RS-500 – 36/46T; Rear Cassette: 105 5800 – 11/28T. I’d like to swap my rear derailleur for the GRX RX 812 and put on a 11-42 cassette (probably the MTB SLX CS M7000 cassette).
    Will that work?? Thanks

    Reply
    1. Gerard Vroomen says:

      29 April 2020

      Of course! Doesn’t work. AT. ALL.

      Reply
      1. G

        Greg Chen says:

        29 April 2020

        Thanks for the fast reply. It sounds like the largest rear cog I can get would be an 11-34T. Is there another component set up you’d recommend to get a bigger rear cog?

        I’d rather not swap out the front crankset to improve the climbing gear ratio–though it sounds like that’s my only option.

        Reply
        1. Gerard Vroomen says:

          29 April 2020

          you can actually run an 11-36T SRAM cassette on your 2x GRX setup, so with your RX-810 rear derailleur. Works great (I’d say better than the 11-34T).

          Reply
          1. G

            Greg Chen says:

            30 April 2020

            Gerard, I like that recommendation of using an 11-36 cassette with the RX-810.

            One followup on my original question: What’s is the problem with using the GRX RX-812 on the 2×11 setup?
            Is it the problem that the RD can’t handle being on the largest front chain ring (a 46T on my bike) and the largest cog in the back (I’d get the 42T)?
            What if I make sure to never use the larger rear cogs with the big chain ring?
            Or is it something else? Thanks!

            Reply
            1. Gerard Vroomen says:

              30 April 2020

              The derailleur doesn’t have the capacity. So it can reach the biggest cog, but it cannot move far enough to also take up the chain slack that comes from the difference between the large and the small chainring.

              It’s a bit counter-intuitive but the derailleur with the 34T maximum cog (although 36T is fine) has a bigger overall capacity, i.e. can take up more chain slack in total (front & rear together) than the derailleur that has a 42T max cog size.

              Reply
              1. G

                Greg Chen says:

                30 April 2020

                Thanks again. I’m gonna try the GRX 810 w/ 36T max cog. Will report back. Appreciate all the advice!

                Reply
    2. t

      timothy says:

      04 February 2021

      Hi Greg, I have Shimano GRX 817 Di2 so same as 812 on a 2 x and it works fine

      Reply
  51. M

    Mark Spencer says:

    16 April 2020

    I respectfully disagree about 1×11 and Di2. You can program the shifters so that the upshifts are controlled one lever and the downshifts by the other. Once you try this, it becomes so intuitive and you wonder why every bike doesn’t shift this way.

    Reply
  52. E

    Erwin says:

    02 April 2020

    Hi Gerard,
    A lot on not doing Di2 here… but I’m certain on doing it anyway.
    My practical question however is, where do I leave the internal battery? For the Strada there are seat post adapters available, but the Di2 battery doesn’t seem to fit the Exploro seat post. Just throwing it in the frame seems like a bad choice.. Any experiences / tips or tricks?

    Reply
    1. Gerard Vroomen says:

      03 April 2020

      Hi Erwin, nothing wrong with Di2, I just think the price/performance of the mechanical version is higher. For the internal battery, I actually have Di2 on my bike (pre-GRX so with an XTR rear derailleur) and I have my battery in the seattube. Wrapped with bubble wrap so the it doesn’t move around at all and is well-protected, and also easy to pull out if you need to (which obviously you rarely do, but when you do, it’s nice to have something that you can hook a spoke into without even looking).

      Reply
  53. S

    Skyler Holder says:

    26 March 2020

    I was wondering if a Shimano XT MTB 11 speed shifter would work with the grx rear derailleur ?

    Reply
    1. Gerard Vroomen says:

      26 March 2020

      No it won’t. The 11-speed MTB has a cable pull ratio of around 1:1, the GRX is 1.4:1.

      Reply
  54. J

    Janis says:

    21 March 2020

    Hello Gerard

    Will a GRX 600 2×11 with a (officially not recommended) 11-40 casette work? Thanks for the help!

    Reply
    1. Gerard Vroomen says:

      23 March 2020

      If you tighten the B-screw all the way, you can just get the chain on the 40T cog. But this is definitely not recommended, you won’t be happy. With an 11-36 SRAM cassette it works great (in fact it’s quieter than with the Shimano 11-34).

      Reply
    2. y

      youpmelone says:

      01 April 2020

      Yes, very easily. Stock dura ace shifts 11-40 with fast crisp shifts, without adapters, if you know how to set it up. The magic is in the chain lengh. Use Shimano cassettes, 10-42 sram is tricky. But di2 with synchro shift on you can make it work.

      Reply
      1. y

        youpmelone says:

        01 April 2020

        BTW this is on 52/36, 50/34 and 42/26

        Reply
      2. Gerard Vroomen says:

        01 April 2020

        However the question was about GRX 600, not DuraAce. While DuraAce has a little more leeway, in setup, it has the problem that where many people live, it’s not suitable for their offroad adventures as it has no clutch.

        As somebody who sees photos of bikes with clutch-less drivetrains and severe chainsuck on a regular basis (even with the correct setup, guides and protectors installed), I would not recommend DuraAce unless your offroad surfaces are relatively smooth. I’m sure people will post “oh, but I set it up right and I have been riding rough stuff with DuraAce for years without a problem” but my experience tallied across hundreds of customers is different.

        Reply
  55. J

    Janis says:

    21 March 2020

    Hello Gerard

    I’m looking into buying a gravel bike as a allrounder: 80 % urban commuting, 20 % sporty riding, and bike touring in vacation. The GRX 1×11 seem to be a very popular option. Though the low gear would be quite high for touring. The GRX 2×11 have a similar low gear in the standart setupt of 46-30 / 11-34. So just to be sure: The GRX 600 46-30 can be combined with a Shimano 11-42 cassette? Thanks for the feedback and best regards!

    Reply
    1. Gerard Vroomen says:

      23 March 2020

      No it can definitely NOT be combined. There is no rear derailleur that has the capacity to take up the chain length difference between the smallest and biggest gears with that setup. The biggest cassette range you could make work is an 11-36 (SRAM) cassette, a bigger cassette will not work with the 2x rear derailleur. And with the 1x rear derailleur, it won’t have the capacity to take up the slack caused by a 2x crank and its tooth differential.

      Reply
  56. N

    Norm Houser says:

    20 March 2020

    Awesome analysis, thank you! Just wondering what you would think of using an XTR 1x mountain crank 38t chainring with the GRX system–specifically because I want to use a 165mm crank and GRX starts at 170.

    Reply
    1. Gerard Vroomen says:

      23 March 2020

      I wouldn’t do that. Using an XTR crank means your Q-factor would be much bigger than on a road crank. So if you go with XTR, you’d have matching brands on your crank and the rest of your drivetrain but that’s it, the usage doesn’t match. I’d get a proper road crank in 165mm from a different manufacturer. FSA, Easton, Praxis, whatever you like at whatever price point you like, much rather than a Shimano XTR crank that has the right length but everything else wrong.

      Reply
      1. A

        Albert says:

        20 June 2020

        How about an R8000 ultegra with a single ring 40T?

        Reply
        1. Gerard Vroomen says:

          22 June 2020

          With the single ring positioned on the outer ring postion I presume (otherwise your chainline will be terrible, pretty much unridable)? Anyway, the 40T fits easily on the outer ring position.

          Reply
  57. E

    Eric says:

    03 March 2020

    Has anyone tried the GRX Di2 levers with the new Shimano XT or XTR 12 speed derailleur and cassette? Would that combination work or would the software not be compatible? I’m thinking of doing this for a 1x setup using the Shimano 10-45 microspline 12 speed cassette. Thanks for any tips on this…

    Reply
    1. Gerard Vroomen says:

      07 March 2020

      I don’t think that will work, haven’t seen it.

      Reply
    2. y

      youpmelone says:

      10 June 2020

      11 speed works 1x, XT and GRX levers DI2

      Reply
      1. Alexander says:

        09 December 2020

        What about mech GRX plus microspline 12 speed cassette and GRX derailer?

        Reply
  58. T

    Tim says:

    23 February 2020

    Hi Gerard,
    Thanks for all your work and the good tips.
    I would like to go with mechanical GRX 812 1×11. As today I am running always in „high Speed Gears“ the Original 11-42 with 42 in front is a bit low for my personal needs. I would love to have 50 in front.
    Does it work with Wolf tooth grx chainring 46 and 10-42 Sram cassette ? Should be similar in the highest gears. Will it be smooth? Something special to take care ?Another recommendation from your side like minimum 9 teeth rear and 42 front with some setup?
    Thanks in advance and best regards
    Tim

    Reply
    1. T

      Tim says:

      23 February 2020

      Sorry. Should be Long Cage = rx 812. and the 42 front Option could be with e thirteen 9-34 ?!
      Thanks
      Tim

      Reply
      1. Gerard Vroomen says:

        24 February 2020

        You’re going to be missing some gears off-road if 42×34 is your smallest gear I think.

        Reply
    2. Gerard Vroomen says:

      24 February 2020

      The GRX 812 rear derailleur definitely works with the 10-42 cassette, so that in combination with the 46T chainring would give you the gears you need. Nothing really to pay special attention to (other than that you obviously need an xD driver on the rear hub).

      9-42 definitely won’t shift as smoothly.

      Reply
      1. T

        Tim says:

        24 February 2020

        Thank you for your fast help, Gerard!
        So you would prefer also for smooth shifting 10-42 in the back with 46T before 9-34 or 9-39 in the back with original 42T chainring ? No issue to modify rear and front? And no concern about the wolf tooth 46T ?
        Best regards
        Tim

        Reply
        1. Gerard Vroomen says:

          24 February 2020

          There’s nothing wrong with starting with a 9T cog, so it’s not specific to the cog range per se. It’s just that SRAM cassettes shift really nicely with Shimano rear derailleurs, better than the reverse for example. I haven’t had my hands on a Wolftooth GRX chainring so I can’t say anything specific to that, but if it bolts on the crank, I don’t know what else could be a problem. They make nice rings (they also make the rings for our Torno cranks).

          Reply
          1. T

            Tim says:

            24 February 2020

            Great! Issue solved. Thanks a lot, Gerard !
            Best regards
            Tim

            Reply
  59. M

    Martin says:

    11 February 2020

    I’m sold on GRX Di2. You say 1x is a bit silly, but as it comes with servo wave and hoods supposedly better for large hands, I’m in. But I want to keep my options open in case the gear spacing is too coarse. I use 15 gears for the same range with 2×11, so only 11 gears will be interesting. The question is, what’s the best way to prepare for reverting to 2x? Should I go with the 1x groupset, then add the front der. and double rings if I don’t like 1x? Or, go with 2x groupset plus buy the single ring and 11-42 cassette and don’t install the front der. ?
    Am I missing anything?

    Reply
    1. Gerard Vroomen says:

      11 February 2020

      Hi Martin, a few things:
      1) You don’t need to get Di2 to get Servo Wave. The SR-RX810 mechanical levers also have Servo Wave so if that’s important to you, that’s another option.
      2) There’s definitely a difference in the mechanical and Di2 hood shape, but I would try them both before deciding you like one better than the other for big hands. I personally prefer the mechanical, but certainly also know of people who prefer the Di2.
      3) To switch from 1x to 2x requires quite a few parts. The GRX rear derailleurs are not cross-compatible between 1x and 2x. Furthermore, a pure 1x drivetrain would have a left brake lever without shifter. So all in all it would be a little easier to go from 2x to 1x as you use the same left lever and just end up with a lame shifter.
      4) The reason I don’t really like the Di2 1x is that say you try that and end up thinking “great, but I wish I had one more gear”. If you’d spent your money on SRAM AXS, you’d have had that one gear and be a happy camper. But instead, your only option is then to get those GRX 2x parts to convert. Now, odds are that 11-sp is enough for you, or maybe even 12-sp isn’t what you want. And of course some people have Shimano preferences over SRAM. So there are good reasons to like Shimano GRX Di2, but for that money, it should have had an extra cog.

      Reply
      1. M

        Martin says:

        11 February 2020

        For 1x, doesn’t GRX have a wider range cassette than SRAM? Discounting the 10-52 cassette which is silly on a road bike., SRAM maxes at 10-33. That’s not enough. If I could do Force AXS with a 10-40 cassette, I might change my mind.

        Reply
        1. M

          Martin says:

          11 February 2020

          11-50

          Reply
        2. Gerard Vroomen says:

          11 February 2020

          There are many options, see here: https://blog.3t.bike/2020/01/12405/gravel-bike-tech-gears-for-tough-climbs-part-1/

          Reply
          1. M

            Martin says:

            11 February 2020

            Thank you. I was not aware of the other cassettes.

            Reply
            1. Gerard Vroomen says:

              11 February 2020

              That’s why we write the blog! Have fun piecing the puzzle together.

              Reply
  60. C

    Colin Matthews says:

    04 February 2020

    I am putting a bike together using GRX 400 10 speed and the rear mech feels so cheap and plastic, I just don’t trust it. My question is, can I install a GRX 810 rear mech instead as, although 11 speed, I understand it has the same cable pull ratio? Obviously keeping the 10-speed chain and cassette.

    Reply
    1. Gerard Vroomen says:

      05 February 2020

      Hi Colin, I am not sure but I suspect you will have issues trying that (BTW I also think you can trust the GRX 400 derailleur).

      Reply
      1. C

        Colin Matthews says:

        05 February 2020

        Thank you for getting back to me. I have now seen an 810 rear mech and it has the same plastic structural component as the 400. It must be a new manufacturing process Shimano has which I presume will work absolutely fine.

        Reply
  61. e

    erik says:

    23 November 2019

    Just installed the GRX 810 rear derailleur on my gravel bike (canyon grail) w/ ultegra compact 2x gearing. Couldn’t quite get an 11-40 cassette to work w/ the b screw all the way in, but the rest of the shifting is super smooth.. I’m pretty confident an 11-36 would work stock. Just ordered a wolf tooth RoadLink and will give it a go tomorrow as i’d really like to get the gearing of the 11-40 and keep the existing compact 50/34 up front.

    Thought i’d share my experience.

    Reply
    1. Gerard Vroomen says:

      23 November 2019

      Hi Erik, unfortunately the Roadlink doesn’t work with GRX. More about that in the next Gravel Bike Tech.

      Reply
      1. E

        Erik says:

        25 November 2019

        I’ve never used a roadlink type device before but was able to get it working (at least it seems like it is working). Cross chaining big big is a no go though. I’m using the roadlink DM. Looking forward to the next gravel bike tech to see potential issues I’m not aware of!

        Reply
        1. E

          Erik says:

          25 November 2019

          I’m having second thoughts on this and will probably just get an 11-36 and return the roadlink…. don’t want to accidentally destroy my bike by shifting big big by mistake…. w/ the clutch on also seemed like it was binding a bit even in the 50 front 31 back gear (3rd largest cog). new chain so don’t think it’s the length. in the small ring operation of the 11-40 seemed fine though and shifting is fine…..

          at the end of the day will get the clutch of the grx and should get a slightly easier gear than the 11-34 i had before.

          thanks for the feedback!

          Reply
    2. C

      CP says:

      28 November 2019

      I could be wrong but I think….the road link enables you to use a bigger range of cassette, but you still need to stay close to the RD capacity. The total capacity for RD 810 is 40 while your set up is at 46 (50-34 plus 40-11). That maybe the reason, but I could be wrong.

      Reply
      1. Gerard Vroomen says:

        28 November 2019

        Correct, but in addition, the road link puts the GRX derailleur at the wrong angle, unlike how it works on the Ultegra. It’s a bit of a mystery why this is different though.

        Reply
        1. E

          Erik says:

          29 November 2019

          Interesting! BTW, running an 11-36 w/out the roadlink appears to be working flawlessly!

          Reply
          1. Gerard Vroomen says:

            08 January 2020

            Yes it does.

            Reply
            1. C

              ChrisinOSMS says:

              07 July 2020

              Can’t get mine to work on 10s 11-36. Won’t give me the 11t cog with the limit screw disengaged. Running downtube friction shifters so it isn’t an indexing issue. Might move to road link and medium cage 105 or ultegra.

              Reply
  62. Loran says:

    21 November 2019

    Thanks for all the info! Do you think a e13 9-42 cassette would be a good fit for the GRX? Or is the 9 to small?

    Reply
    1. Gerard Vroomen says:

      21 November 2019

      Still testing, answer soon. Just make sure you’re subscribed to the newsletter.

      Reply
      1. A

        Ash says:

        06 December 2019

        Also curious on how whether the 9-46 works with the GRX longcage (rx812). Seems like the ideal range

        Reply
        1. Gerard Vroomen says:

          06 December 2019

          That next post is almost ready

          Reply
          1. A

            Ash S says:

            07 December 2019

            Can’t wait!
            Thanks for all your writeups! Super well received.

            Reply
            1. Gerard Vroomen says:

              17 January 2020

              You can find that post here now: https://blog.3t.bike/2020/01/12405/gravel-bike-tech-gears-for-tough-climbs-part-1/

              Reply
  63. C

    Carl Anderson says:

    20 November 2019

    Hello Gerard,

    Thank you for all the insight into the gearing options. Have you had any further experience with running an 11-36 cassette with the 2x setup? I currently have a 3x crank and my lowest gear is a 28 front with a 34 rear for climbing the old logging roads around here. Any info or suggestions how I could stat in the gear range with GRX would be greatly appreciated.

    Regards,

    Carl

    Reply
    1. Gerard Vroomen says:

      20 November 2019

      We’re still testing a bunch of setups. Story coming soon. Just make sure you’re subscribed to the 3Talk newsletter and you’ll be the first to know!

      Reply
  64. A

    Alexander says:

    18 November 2019

    Hello Gerard, I realy like mechanical brakes(bb7) and still not find the solution for their application on GRX 1×11 system. I checked shimano compatibility table and found that my favourite R7000(11 speed) levers can work with RD-RX 810. Do you know will R7000 or other Shimano mechanical levers work together with the RD-RX812(It will be used with 1175/1195 10-42 cassets and sram force 1 dub Crankset) ?

    Reply
    1. Gerard Vroomen says:

      18 November 2019

      I don’t *know* but logic tells me that if the same GRX levers can shift the 810 and 812 rear derailleurs, they must have the same pull ratio. So if the R7000 lever works with the 810, it should work with the 812 too. But I could be wrong, maybe I’m missing something very clever (or stupid) that Shimano did with those levers.

      Reply
  65. Rob W says:

    09 November 2019

    Maybe this was answered, but can I run the GRX RD-RX817 long cage DI2 with a 2x setup? I like to start with 1x but if I’m doing a ton of flat garvel, have the option of putting my Ultegra CX setup crankset on and swapping a longer chain. It seems like it should work, maybe a bit slower shifts?

    Reply
    1. Gerard Vroomen says:

      09 November 2019

      No, impossible, it doesn’t have the capacity to compensate for the difference in teeth between the front rings. We tried, it failed.

      Reply
      1. J

        James K says:

        21 January 2020

        Gerard – would it work if you could electronically disable / lock out shifting to the biggest gears in the cassette when in the big ring? Limit the shifting to the max tooth gap it can cope with.
        Also – is there any software limitation built into the Di2 system that prevents the 817 rear derailleur from working with a front derailleur?

        Reply
        1. Gerard Vroomen says:

          21 January 2020

          On both counts, not that I’m aware of.

          Reply
        2. y

          youpmelone says:

          10 June 2020

          rx817 works with ultegra/dura ace 52/36 in 11-40 cassette.
          Perfectly, no adapters no huge b screws.

          I recently started keeping the chain short and have the synchro shift running, so you never go 52/40.
          Speeds the shifting up.

          As actually does Dura Ace, Ultegra and Ultegra RX, on 3 BMC roadbikes
          On the Open it runs 10-42 and 46/30 (rotor) Easily, just the shift to 10 is a bit slow and clunky.

          Reply
    2. S

      Stiphodon says:

      03 December 2020

      I’m planning on doing this 2x set up with rx817, grx di2 shifters and FD, and a 11-42t with easton 47/32 up front. I read on another forum the rx817 RD won’t work with synchro shifting as shimano have designated it 1x only. Did you need to modify the software somehow?

      Reply
      1. Gerard Vroomen says:

        03 December 2020

        You can also make that setup work with the RX812 and then you have synchro shifting.

        Reply
  66. K

    Keith says:

    08 November 2019

    Hi,

    Trying to run a SRAM XX1 10-42 cassette with a GRX 812. RD.. I’m getting poor/rough shifting even with the derailleur properly setup. Is it crucial to run a SRAM ‘narrow/wide” chain? (Currently trying a Shimano Dura Ace chain).

    You stated it worked flawlessly for you, which chain were you using? Did you need to swap out the jockey wheels for narrow/wide ones like SRAM uses to perfect the shifting?

    Thanks for any input/advice!

    Reply
    1. K

      Keith says:

      08 November 2019

      Forgot to mention, I’m trying to run the GRX 812 RD with Dura Ace 9120 levers, but don’t think that’s causing the rough shifting, as even Shimano says the GRX stuff is compatible with other groupsets?

      Also, derailleur hanger is dead straight, limit screws properly set, indexing dialed in. It runs through all 11 gears, but clunky and noisy, and some up/down shifts are slow. Everything is brand new, maybe I just have to give it time to break in?

      Reply
      1. Gerard Vroomen says:

        09 November 2019

        Definitely breaking in the parts a little helps with all shifting setups, a 2 hour ride should take care of that though.

        Reply
      2. J

        Jack says:

        03 April 2020

        Did you get it to work in the end Keith? I might be trying something similar.

        Reply
    2. Gerard Vroomen says:

      09 November 2019

      We used a Shimano CN-HG601 chain, but I don’t think it matters much. There are no narrow-wide chains (or more correct, all chains are). It’s the chainrings that are narrow-wide to match the “natural” way in which all chains are already narrow-wide.

      Chain length is crucial though, for example a 42T chainring with a 10-42 cassette needs 112 links on the Exploro. And then there is the B-tension. You should also check the exact rear derailleur hanger alignment.

      Reply
  67. D

    Dan says:

    08 November 2019

    Anyone already tried using a shimano road fd with shimano grx 2×10 crank? is there a hack or its not possible at all.

    Reply
    1. Gerard Vroomen says:

      08 November 2019

      The GRX crank has the rings a little further outboard than the standard Shimano road cranks. As a result, the GRX derailleur also has the cage a little further outboard (frames have the front derailleur mount in a fixed position, otherwise it would become a mess between different frame makers, so to move the cage out, Shimano had to put that change in the derailleur itself).

      So if you put a GRX crank with a standard front derailleur, the cage will not line up correctly. Shimano says it’s not compatible. You can probably make it work (shims under the mount if it is a detachable model, etc) but it won’t be pretty. Same problem trying to use a standard road crank with a GRX front derailleur; the cage won’t line up.

      Another issue is the curvature of the cage. The road cage is designed to match bigger chainrings than the GRX cage, so the cage won’t match the GRX rings that nicely. It will work (just like sub-compact cranks work with standard road front derailleurs), but not as crispy as using a GRX front derailleur with a GRX crank.

      But you could make a GRX setup with a standard road crank AND standard road front derailleur. It changes the chainline a bit, but not to the extent that it won’t shift. Chainline is a pretty flexible dimension, in fact Shimano road and GRX groups have the cassette in exactly the same position on the rear hub. So the center of the cassette (the “cassette chainline” so to speak) is the same even though the center plane between the front chainrings (the “crank chainline” so to speak) is different. And yet both road and GRX groups shift fine. Hence putting a road crank and front derailleur on a GRX bike simply puts the cassette/chainring positions back to where they are on all disc brake road bikes, not a problem.

      Reply
  68. H

    Hans says:

    07 November 2019

    Pointing out the obvious and I know I’m not the only one doing this. .

    Not to rain on Shimano’s GRX or Sram’s AXS/Eagle parade but for 3+ years I’ve been running a 2×10 mechanical Sram (2×11 will also work) drivetrain on my cross bike that has a greater range than the latest and greatest offerings and it works without a hitch with crisp shifting and no front derailleur cage rub at either end of the spectrum.

    Here are the specs, remember this is 2×10 mechanical but a 2×11 mechanical setup will also work. Sram Red Double Tap shifters, Sram (Quarq power meter) 48×34 cranks (any 48×34 crank set should also work), Sram Red Yaw front derailleur, Sram XO long cage rear derailleur and the last piece of the puzzle is an 11-40 Sunrace cassette. The Sunrace cassette is a boat anchor but it was inexpensive. (Sram offers a light 11-36 cassette that I have but its reserved for race day.)

    From this point I’m considering going with either 48-32 or 46-30 cranks and an 11-42 cassette. As pointed out previously the 46-30 cranks may or may not fit the frame so the 48-32 cranks are the better option plus 48-32 cranks more useful for road riding in the big ring.

    The 34×40 low end and 48×11 high end covers just about anything out there and I’ve never had to walk up anything including the infamous 20+++% grades in Vermont.

    Going with 48-32 cranks and an 11-42 cassette wouldn’t change the high end but would result in a 32×42 low end which is absolutely ridiculous.

    I can’t take credit for this setup as it is fairly common knowledge in the more mountainous regions of New England and I’m sure elsewhere around the globe.

    Shimano and especially Sram know about mixing and matching their components but why tell anyone, that would defeat the purpose of hyping their newest offerings.

    New is not always better.

    Reply
  69. j

    jeff says:

    25 October 2019

    Could you run GRX levers with an XT rear derailleur (mechanical or Di2) for the 11-46t range? I was actually thinking GRX levers, XT-SGS rear, 11-40t cassette, and 48/31t crankset for wild wide range…

    Reply
    1. Gerard Vroomen says:

      28 October 2019

      OK, here’s the deal. You can NOT shift a mechanical Shimano mountain bike rear derailleur with a mechanical Shimano road shifter. The pull ratios are different.

      You CAN shift a Di2 MTB rear derailleur with a Di2 road shifter. So you can make a 1x setup with a slightly bigger cassette that way.

      But you can NOT easily make a 2x drivetrain that way. Because for Di2 to work, the front and rear derailleur need to be from the same family, i.e. both road or both mountain. If you try to connect the Di2 shifters with a road front derailleur and a mountain rear derailleur, the electronics won’t work. Of course you could also use a mountain bike front derailleur, but it would require a different front derailleur mount, a different position, smaller rings in the front, etc, and pretty soon you’re simply riding a hardtail mountain bike with ultra low gears and not much at the top end.

      Reply
      1. C

        Corvid Cycles says:

        16 January 2020

        You can use a Wolf Tooth Tanpan, which adjusts the pull ratio to allow Shimano road (and GRX) shifters to work with Shimano MTB rear derailleurs.

        Reply
        1. Gerard Vroomen says:

          17 January 2020

          Yes, you can use a Tanpan.

          Reply
      2. L

        Lloyd says:

        04 April 2020

        Sorry I am jumping in here a bit late. I was thinking of putting together a 1x di2 bike with:
        – GRX di2 shifters
        – XT CS-M8000 11-46 casette
        – mtb (RD-M9050-GS or RD-M8050-GS) derailleur.
        Is that a combination that would work? It seems from your comment immediately above it would.

        Reply
        1. Gerard Vroomen says:

          04 April 2020

          Problem with mixing road and mtb parts with Shimano is that they don’t really want you to do it. So you’re always one firmware update away from it not working anymore. For example, it used to be simply to pair say DuraAce shifters with an XTR rear derailleur, but then that stopped working. So now you need to do the setup with a DuraAce rear derailleur and then swap out for the XTR.

          An easier solution is to use the GRX rear derailleur with the 11-46T, it works but it’s noisy and on the limit so not officially allowed. So easier but not great.

          My preferred solution is GRX in combination with a SRAM 10-42T cassette. That will get you the same gear range (as long as you make your chainring 10% smaller than you would in combination with the 11-46T cassette). More about all that here: https://blog.3t.bike/2020/01/12405/gravel-bike-tech-gears-for-tough-climbs-part-1/

          Reply
          1. M

            Mikkel says:

            06 November 2021

            Hey Gerard, are you saying 11-46T (CS-M8000) is a no-go with RD-RX817?

            Reply
            1. Gerard Vroomen says:

              06 November 2021

              It “works” but not quite up to the level I would want from a drivetrain. So it’s a bit noisy and shifting isn’t always crisp. A better solution would be to scale your whole drivetrain down 10%, so going with a 4T smaller chainring and the SRAM 10-42T cassette. That works flawlessly with the GRX long cage rear derailleurs.

              Reply
              1. M

                Mikkel Bondesen says:

                09 November 2021

                Thank you so much, and thank you for taking the time to help!

                Reply
  70. P

    Przemek says:

    24 October 2019

    Hi Gerard,
    Which BB would you recommend for GRX crankset in Exploro frame? I noticed You are not using Hollowtech 2 in any of the available Exploro models. Is there any particular reason for that? Are wider spindles superior to 24mm? Reason I’m asking is I want to switch to 2x GRX Di2 in my Exploro.
    best regards!
    Przemek

    Reply
    1. Gerard Vroomen says:

      24 October 2019

      The whole world has gone to bigger diameter axles, except Shimano. They don’t tend to like things they didn’t invent themselves. There’s nothing wrong with 24mm axles, don’t get me wrong, but you can save some weight by going oversized. But there are tons of BBs for Hollowtech II cranks and BB385EVO frames, so not difficult to find one (Enduro, Wheels Mfg, Kogel, Token, etc, etc, etc).

      Reply
  71. T

    Trond says:

    15 October 2019

    Thanks for the article. Is there any way to use the GRX/Hoods/Shifter with an 11-speed 1x SRAM Force derailleur and cassette?

    Reply
    1. Gerard Vroomen says:

      15 October 2019

      I don’t think so but why would you want to do that? You can combine a GRX shifter and rear derailleur with a SRAM cassette, that’s no problem, but mixing the shifter and derailleur from different brands won’t fly.

      Reply
      1. T

        Trond says:

        02 December 2019

        Thanks for the reply. I only want to do it because I already have the parts from SRAM, and don´’t get along with the sram hoods. I take it from your answer that the shifters are pulling different wire-lengths on each shift.

        Reply
        1. Gerard Vroomen says:

          02 December 2019

          Hi Trond, you’d have to try it, I am not 100% sure but that would be my guess.

          Reply
          1. S

            Sergi says:

            25 January 2020

            I’m exactly in the same position, I want to change SRAM Rival 1×11 shifters for Shimano’s GRX but I dont want to change the rival derrallieur which it actually works quite good compared to the several problems that the rival Brakes gave me

            Reply
            1. Gerard Vroomen says:

              26 January 2020

              I’d still be quite surprised if that works.

              Reply
  72. Gary says:

    09 October 2019

    I have Marin Four Corners with drop bar and post mount calipers. So, could I mix a set of XT hydraulic or Magura MT5 brakes with GRX levers?

    Reply
    1. Gerard Vroomen says:

      09 October 2019

      I’m not sure, in general Shimano likes to make the mixing of components impossible, so I would almost assume the lever and brake are compatible in this case.

      Reply
      1. Gary says:

        10 October 2019

        Thanks a lot! one more question, if I’m to use Sram XD 10-42T cassette, is it better to use Sram Narrow Wide chain or default Shimano chain?

        Reply
        1. Gerard Vroomen says:

          10 October 2019

          Actually both work, but we find the SRAM chain to be a little quieter (after the first ride where chain, cassette and chainring always have to settle in regardless of brand).

          BTW, any chain is narrow-wide, that’s inherent in the design of the paired plates. It’s the chainrings that are either constant tooth width (for 2x applications) or alternating narrow/wide teeth (for 1x applications). And despite the different names, stories and patents, all manufacturers that make 1x chainrings use some version of this principle.

          Reply
          1. Gary says:

            11 October 2019

            Thanks for the info Gerard. Btw, just confirmed XD – GRX Compatibility. Marin Headlands comes from factory with Shimano GRX Levers, 1x drivetrain and 10-42T XD cassette. https://www.marinbikes.com/ww/bikes/20-headlands-2

            Reply
            1. Gerard Vroomen says:

              11 October 2019

              Hi Gary, yes the 10-42 is compatible, we already had that in the lab and mentioned that in the article. Just not sure the XT or Magura brakes are compatible.

              Reply
              1. Gary says:

                11 October 2019

                It’s ok. I wish SRAM releases new brifter with similar ergonomic, or at least similar brake lever pivot point. Then, it’s all checked for me. Because Rival/Force groupset still available with post mount.

                Reply
                1. Gerard Vroomen says:

                  11 October 2019

                  Even new Red AXS is available in post mount, although that is barely advertised.

                  Reply
                  1. Gary says:

                    15 October 2019

                    Yap, SRAM is more flexible. There’s a rumor, GRX calipers are actually XT calipers since the cooling fins look similar. Well, I think for 1x setup, I only need GRX brifters and GRX long cage rear derailleur. Then mix and match other components.

                    Reply
  73. R

    Ricardo says:

    03 October 2019

    Hi Gerard,

    I currently habe SRAM Apex 1 on my bike and although I have very much liked 1x, the brakes have given me so many headaches that I want to switch to Shimano soon. I take it you’d recommend mechanical over electronic if I want to stick with 1x? (And I most definitely prefer 1x for gravel)

    Reply
    1. Gerard Vroomen says:

      03 October 2019

      Mechanical works great, so I don’t really see the need for Di2 in this 1x case. And of course, you can run the same brakes regardless of mechanical or Di2.

      Reply
      1. R

        Ricardo says:

        03 October 2019

        Having honest expert insight is always helpful. Thanks a lot!

        Reply
      2. R

        Ricardo says:

        03 October 2019

        Two more questions…

        1. If you can technically run a SRAM 10-42 casette with GRX shifters, I suppose a SRAM 11-42 would totally work, right?

        2. Would the chainline offset really preclude users from using third party 2x cranks?

        Reply
        1. Gerard Vroomen says:

          04 October 2019

          1) Yes, in fact a SRAM cassette in a GRX drivetrain runs a little smoother and less noisy than a Shimano cassette. Don’t ask me why.
          2) No, it’s not a big deal. Mostly because there is not one perfect chainlink, there is a range that works (and that you can even “tune” if you want, based on what gears you are in most, or care most about.)

          Reply
          1. R

            Ricardo says:

            08 October 2019

            Thank you very much!

            Reply
          2. C

            CP says:

            28 November 2019

            I notice the drive train was quieter on sram cassette as well, and I think I may know the reason.
            I ran the following 1X cranksets on the GRX equipped Exploro: GRX, Easton, Force and Ultegra R8000 with woof tooth 1X chainring.
            The GRX was the noisiest of all while the Ultegra crankset was the quietest.
            The Easton was almost as quite as Ultegra, and Force wasn’t far behind.

            I speculate that the longer chianeline of the GRX crankset along with the ramp on the Shimano cassette (which is designed to work with Shimano components) might be the culprit of it.

            I also noticed a lot more friction noise from chain/chainring on the GRX when I put the chain on the 42T cassette.

            I know the Shimano moved out the GRX to 50mm for more tire clearance for the FD but if you are running a 1X, you shouldn’t have such issues.

            I like the GRX a lot but if I were to run the 1X drivetrain, I would run a different crankset with a shorter chainline.

            Reply
            1. B

              Brandon says:

              23 December 2019

              I am running GRX crankset with Wolftooth 46T chainring on my 3t Exploro Pro GRX. I have also noticed considerably more noise and grinding in the largest cogs, with the 42T being quite rough. Are there significant performance losses and/or premature wear associated with this configuration? Since the chainring is mounted on the inside of the GRX crank arms, I am thinking of spacing it in a few mm to see if it helps.

              Reply
              1. Gerard Vroomen says:

                29 December 2019

                Well, noise = friction and friction = wear. So it has an effect. That said, chainrings are designed for this type of wear, so it’s not like you’ll wear them out in a single ride now but yes, it does have an effect.In my humble opinion, the Shimano chainlink is too wide for 1x, it’s OK if you mostly use the small cogs but if you’re regularly in the big cogs, the chain is too skewed.

                Reply
                1. A

                  ADAM MR ROSE says:

                  26 January 2020

                  Is that why you spec the Praxis crank on the GRX pro? thanks!

                  Reply
                  1. Gerard Vroomen says:

                    26 January 2020

                    The PRO GRX is available with either crankset. The advantage of the Praxis (or for example the FSA crank on other bikes) is that it has a 30mm crank. So it takes advantage of the oversized bottom bracket shell.

                    Reply
  74. S

    Scott Brookes says:

    04 September 2019

    Hi,
    here’s a good one…
    Shim another show an XT cassette with a 46T option on their GRX website:
    https://bike.shimano.com/de-DE/product/component/grx-11-speed/CS-M8000.html

    do you have any idea where this could fit in, or would it be Di2 only?

    many thanks for your honest thoughts!
    SB

    Reply
    1. Gerard Vroomen says:

      06 September 2019

      We actually have that on the testing list, so an update on that cassette will follow in a few weeks.

      Reply
      1. Paolo says:

        07 October 2019

        Hello Gerard,
        did you finalize the testing with the 11-46 cassette and the GRX mech? It would be great to know if one could fit the 11-46 cassette as well, even though shimano says the maximum cog size is 42.
        Thanks!
        Paolo

        Reply
        1. Gerard Vroomen says:

          07 October 2019

          You can make the 11-46 shift, but it’s not great. It’s noisy and doesn’t shift that smoothly in the 3 biggest cogs. Best to stick with 10-42, that works perfectly and has the same range (actually slightly bigger at 420% vs 418%).

          Reply
          1. Martin says:

            23 October 2019

            I guess the question hints at having a better gear ratio at the low end. Do you think one could achieve this via different chain ring sizes?

            The typical 1-by GRX setup is 40 x 11-42T; could I swap the chainring for a e.g. 36 (if and when available) and the cassette for the mentioned SRAM 10-42T and thus only loose a little bit of gear ratio on the high end (3.64 vs. 3.6) but gain a lot on the low end (0.95 vs 0.86)?

            That’s probably why the 11-46 is of interest otherwise (3.64 to 0.87 gear ratios).

            Reply
            1. Gerard Vroomen says:

              23 October 2019

              Yes, that’s what the chainring choice accomplishes. The cassette determines the range (382% for an 11-42T, 418% for an 11-46T cassette, etc) and then you pick the right chainring to set the smallest gear you get.

              For example, I really don’t want to walk when I’m riding, no extra top end speed can make up for having to walk a few miles. So my usual setup on tough rides is an 11-42T cassette with a 36T chainring. Yes, 36x11T is not a big top end gear, but who cares. And with 36x42T as your smallest gear, you can ride up anything.

              Reply
              1. W

                Walter says:

                08 January 2020

                Is there currently a 36t chainring available for the GRX?

                Reply
                1. Gerard Vroomen says:

                  08 January 2020

                  Right now it seems the smallest is a 38T from Wolftooth.

                  Reply
                  1. W

                    Walter says:

                    08 January 2020

                    Ok, that is all I was able to find, but thought maybe I was missing something. Thanks for the reply.

                    Reply
                    1. C

                      Craig says:

                      27 April 2020

                      I’m using a RaceFace 36T just fine on the 10×42.

                    2. Gerard Vroomen says:

                      27 April 2020

                      On a GRX crank?

  75. R

    Rasmus says:

    04 September 2019

    Wonder if/when someone will make something like a 12 speed 10-36 or 10-40 cassette, and whether you’d need an Eagle derailleur to use it or if it would work with the Red derailleur, but in any case I have a feeling that it could be a very useful cassette for Stradas and Exploros. It’s not that hard to find a 34t front chainring, and that should give a decent climbing gear.

    Reply
    1. Gerard Vroomen says:

      06 September 2019

      Yes, a 10-36 and 10-40 or thereabouts would be great, right now the gap between 10-33 and 11-50 is too big.

      Reply
  76. H

    Hamish Grant says:

    04 September 2019

    Hi Gerard
    Interesting article. You are reflecting the situation I found myself in when building an Exploro this year. Trying to get a wide range groupo was going to involve a fair bit of compromise and a bit of garage project. Then Rotor released the 1×13 group and I went there. Works pretty well. I have a 44T CR and a 10/46 cassette. So I get 1:0.95 and I am using it for road and gravel racing. The Exploro feels great. Be interested in your take on the Rotor approach.

    Reply
    1. Gerard Vroomen says:

      04 September 2019

      Hi Hamish, the Rotor group could be a topic for a future Gravel Tech segment, thanks!

      Reply
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