SRAM Force gravel history
When the Exploro started the trend towards performance gravel bikes, SRAM Force 1 was the first spec we offered. We’ve been in close contact with SRAM ever since, so in early 2018, they invited me to San Luis Obispo to see the new SRAM Force & Red AXS eTap and get some feedback.
I loved the technology but didn’t like the gear ratios they proposed. I thought we needed lower gears for 2x and a wider range cassette for 1x.
For 1x, there were solutions woven into the AXS fabric. Force AXS is cross-compatible with anything else in the AXS family, so you can combine the Force AXS road shifters with an Eagle AXS rear derailleur and get massive gear options.
For 2x, there really wasn’t any such option. I pleaded, begged and prayed for a fourth cassette. Ideally a 10-42T or 11-42T for big climb 1x riding (so a little closer-spaced than the Eagle options), but at the very least something like a 10-36T for fast 1x and any 2x.
SRAM Force for gravel today
SRAM Force AXS WIDE is the newest addition to the SRAM AXS family, giving us more options for Force AXS gearing. My ideal setup involves using 2 of them but not the other 2 and I’ll explain why. But first let’s look at all four parts:
New 10-36T cassette
This is a beautiful cassette combo, as a 12-speed cassette with this range really gives you options. On smoother terrain, it makes for a great 1×12 set-up giving you simplicity and access to the right gear all the time. For really tough terrain, it’s a great cassette for a 2x setup.
Compared to the 10-33T, the 10-36T has the following gears (differences in red):
New bigger range rear derailleur
The original Force AXS rear derailleur is rated for a maximum cog size of 33T. And any testing with bigger cassettes didn’t really render positive results, unlike for some other derailleurs. For example, a mid-case Force1 rear derailleur is rated up to 36T but can very smoothly shift an 11-42T cassette.
So with the new 10-36T cassette comes a new rear derailleur rated up to 36T. This new derailleur is meant for the 10-36T and 10-33T cassette, while the original derailleur remains in the line for the 10-26T, 10-28T and 10-33T cassettes.
New 43/30T cranks
To boost the low gearing even more, SRAM is also introducing a crank with smaller rings. It has several features that differentiate it from the other Force AXS cranks (46/33T, 48/35T, 50/37T):
- Chainring BCD (bolt circle diameter) is 94mm instead of 107mm. It needs to be smaller because otherwise the bolts would be in the way of the chainring teeth. So the rings are not cross-compatible, to use the smaller rings you need the new crank.
- Chainline is 47.5mm instead of 45.0mm for the other cranks. Note that the cassette position does not change, so the crank is moving relative to the cassette. This is not a problem in itself, chain line is not a fixed entity, you can tune it a bit. For example if you spend more time on the big cogs, having a narrower chainline makes sense. Anything from 45-49mm works fine on SRAM AXS bikes. That said, presumably this smaller crank is for people who spend a lot of time in their smaller gears (i.e. bigger cogs), so moving the chainline out is a bit strange.
- The benefit of this wider chainline is that by moving the crank outward, the front derailleur can also move outward. This increases tire clearance, which is handy since the eTap front derailleur is a bit bulky due to the battery. So while the original front derailleur may work next to tires up to 50mm, the new one will work up to 55mm (these are rough guidelines, always check for sufficient clearance on your own bike).
- Unfortunately, the Q-factor also increases for the new crank (as the rings move out, so does everything else). That’s a shame, as a lower Q is more efficient and more aerodynamic for most riders.
New WIDE front derailleur
Because the chainrings are smaller, the front derailleur needs to sit lower. But the original Force AXS front derailleur can’t go any lower than where the 46/33 chainring sit (all frame makers follow the same guidelines for the front derailleur mount, so those slots simply end somewhere and then you cannot slide your front derailleur any lower).
This new derailleur simply moves the attachment bolt up, which means the front derailleur cage moves down. The curvature of the cage is also adjusted to better match the smaller rings. And the lateral position of the cage is moved out 2.5mm to match the wider chainline of the new 43/30 crank.
My favorite new Force AXS 2x setup
As I mentioned, 33×33 is too big a smallest gear for many, so having smaller options is great. Now you have three options:
- Use the new 10-36T cassette with the new 43/30T crank for a smallest gear of 30×36
Pros: very small gear
Cons: wider chainline, wider Q-factor
- Use the new 43/30T crank with the existing 10-33T cassette for a smallest gear of 30×33
Pros: pretty small gear, very small steps throughout the range
Cons: wider chainline, wider Q-factor, not as small a gear as option 1
- Use the new 10-36T cassette with the existing 46/33 crank for a smallest gear of 33×36
Pros: pretty small gear, narrow chainline & Q-factor
Cons: not as small a gear as option 1, you don’t have the 14T cog that option 2 has
For me, if you’re looking for a 2x gravel drivetrain, option 3 is the clear winner in most situations. Best Q-factor, nice 33×36 gear for when the going gets tough, close spacing throughout with the only drawback being you don’t have the 14T cog. So that means you use two Force AXS WIDE components (cassette and rear derailleur) but not the other two (crank & front derailleur).
Only if that 33×36 isn’t small enough or if you run a 2.1″ tire would I consider option 1 and sacrifice Q-factor. Actually, I wouldn’t sacrifice Q-factor even then. I’d rather take the Force/Eagle 1x setup with a small Q-factor (even better the ultra-narrow 3T Torno crank) over the WIDE crank with the wider Q.
Whether option 3 is better than a 1x Force/Eagle setup, that really depends on your preferences on a range of factors:
- Force/Eagle: simpler, easy to tailer to extremely low or top gear, more tire clearance
- Force AXS 2x: more closely spaced gears
For more on Force/Eagle set-ups, check out this article.
This is the cassette we’ve been waiting for, the 10-36T makes SRAM gravel options using Force AXS eTap finally viable. It can be used in two ways:
- 1x setup focused on fast terrain
- 2x setup tailored towards tough terrain.
It would have been great if the new sub-compact crank didn’t have the bigger Q-factor but the 46/33T crank will render a small enough low gear for most riders while keeping the narrow Q.
Further reading: Hacking the Wide on your 3T
Own an AXS bike already and want the 10-36T cassette without buying a new rear derailleur? Want those 43/30 chainrings but not the wide Q-factor?