What gravel tire do I need? – Gravel Bike Tech

Often people will recommend a certain gravel tire based on terrain you ride. But that's only half the story.

Posted by Gerard Vroomen - 01 June 2020

What size is my gravel tire anyway?

What it most likely is NOT is what it says on the label. To understand why and learn about WAM (Width as Measured) and RAM (Radius As Measured), read it here.

So which tire do I need?

The gravel tire you need depends on 3 main factors. People often focus on the terrain, for example by defining 3, 6 or 20 types of gravel and then recommending the perfect gravel tire for each. But that ignores a major factor: the rider.

The rider has (or doesn’t have) certain skills to keep the bike under control and avoid flats. The rider also determines the speed. The winner of Dirty Kanza may use 35mm tires, but if I use the same tires, I will likely end up walking a few miles. Especially if it’s wet and my slower speed sees me sinking into the mud more than the faster rider who floats over it.

Furthermore, roots, rocks and cracks get smoothed over more at high speed than at low speed where you really bump into everything. This image explains it:

Taking into account both terrain and speed, the graph of suggested (gravel) tire widths looks something like this (it’s just an indication, don’t get too hung up on a mm here or there). And again, if you need a refresher on WAM, just check it here.

Recommended gravel tires for Exploro RaceMax

Because WAM depends partially on the inner width of the rim, you might want to use a different tire on a different rim. This is not only important for tire fit but also for its performance. A very wide tire on a narrow rim is very flexible sideways, meaning that in corners your handling won’t feel as secure. So as you move from road tire widths (28-35mm) to real gravel widths (35+mm), it pays to also look for a wider rim.

As the WAM changes, so does the RAM. This is not so critical in most cases, but in the case of the Exploro RaceMax where we try to optimize the clearance between the tire and the seat tube cutout, we do target a specific RAM for optimal performance. We recommend the tires below based on:

WAM & RAM
Tire profile
Casing design
Rolling resistance (keeping in mind the profile)
Puncture resistance (keeping in mind profile & weight)
Aerodynamics (this one is tough as we can’t put every tire in the wind tunnel)

Please note that while WAM & RAM measurements are more accurate than the dimensions on the tire label, there are still variations:

While inner rim width is the biggest rim factor, the exact shape of the rim bed and depth of the flanges also affects the shape and size of the tire mounted.
Tires vary due to production conditions, so two tires from different batches may size differently. That means an individual tire’s RAM may be off by a few mm (much less for WAM), and that is a lot when you’re trying to create a proper fit between tire and seat tube.

So with WAM and RAM, we’ve gotten closer to a solution but we’re not 100% there yet.

Always check for sufficient clearance between the specific tire you use and your bike frame irrespective of WAM & RAM listed here.

35-42mm low profile (oversized road)

RIM INNER WIDTH	BRAND	TIRE MODEL	ETRTO	WAM	RAM

19mm inner width	Panaracer	GravelKing slick	35-622	37	352
19mm inner width	Panaracer	GravelKing slick	40-622	39	354
19mm inner width	Pirelli	Cinturato Velo	35-622	34	350

23mm inner width	Panaracer	GravelKing slick	35-622	38	352
23mm inner width	Pirelli	Cinturato Velo	35-622	35	352

25mm inner width	Pirelli	Cinturato Velo	35-622	35	349
25mm inner width	Panaracer	GravelKing slick	35-622	38	352
25mm inner width	Pirelli	Cinturato Velo	35-622	37	350

29mm inner width	Pirelli	Cinturato Velo	35-622	39	348
29mm inner width	Panaracer	GravelKing slick	35-622	40	351
29mm inner width	Panaracer	GravelKing slick	40-622	42	352

35-42mm with profile

RIM INNER WIDTH	BRAND	TIRE MODEL	ETRTO	WAM	RAM

19mm inner width	Schwalbe	G-One Allround	35-622	36	351
19mm inner width	Panaracer	GravelKing SK	35-622	38	353

23mm inner width	Schwalbe	G-One Allround	35-622	37	351
23mm inner width	Panaracer	GravelKing SK	35-622	38	353

25mm inner width	WTB	Riddler Fast light TCS	37-622	39	352
25mm inner width	Schwalbe	G-One Allround	35-622	38	351
25mm inner width	Schwalbe	G-One Speed TLE	35-622	37	350
25mm inner width	Schwalbe	G-One Speed TLE	40-622	40	354
25mm inner width	Panaracer	GravelKing SK	35-622	38	351
25mm inner width	Panaracer	GravelKing SK	40-622	41	354
25mm inner width	Pirelli	Cinturato Gravel H	35-622	37	350

29mm inner width	Schwalbe	G-One Allround TLE	35-622	39	348
29mm inner width	Schwalbe	G-One Speed TLE	35-622	40	348
29mm inner width	Schwalbe	G-One Bite TLE	40-622	42	352
29mm inner width	Schwalbe	G-One Speed TLE	40-622	42	352
29mm inner width	Panaracer	GravelKing SK	35-622	41	350
29mm inner width	Pirelli	Cinturato Gravel H	35-622	40	350

53-61mm with profile

RIM INNER WIDTH	BRAND	TIRE MODEL	LABEL	WAM	RAM

19mm inner width	Vittoria	Barzo isotech 4c tnt	27.5×2.25″	55	346
19mm inner width	Vittoria	Barzo isotech 4c tnt	27.5×2.1″	53	343
19mm inner width	Schwalbe	G-One Allround TLE	27.5×2.25″	58	343

23mm inner width	Panaracer	Gravel King SK	27.5×2.1″	56	345
23mm inner width	Vittoria	Barzo isotech 4c tnt	27.5×2.1″	53	345
23mm inner width	Schwalbe	G-One Allround TLE	27.5×2.25″	58	345

28mm inner width	Vittoria	Barzo isotech 4c tnt	27.5×2.1″	55	351
28mm inner width	Schwalbe	G-One Allround TLE	27.5×2.25″	61	352
28mm inner width	Continental	RaceKing Perform.	27.5×2.0″	54	348
28mm inner width	Schwalbe	G-One Bite	27.5×2.1″	56	348
28mm inner width	Panaracer	Gravel King SK	27.5×2.1″	58	351