6

The title line says it all.

Just by looking at the pictures of the forks used for gravel bikes, and before reading the specs, it's evident that a 2.25″ won't fit. Is the term "gravel" today already tied to, say, 700c-38, and precludes such a lavish size?

57-622 is a more formal way to describe 29″×2.25″ while guaranteeing that 1- the bead will fit (622) and 2- the rim width will also fit (57). (Here the 622 matches, but 38 is too narrow.) But that doesn't say anything about whether the wheel will fit back in the frame.

The 2.25″ presumably accounts for ribs and studs.

Edit

The objective from the question is to determine whether a "gravel bike" (whatever that means) is a suitable replacement for a hardtail when frostcycling. The idea is that if you're riding on paved paths, the front suspension is entirely unnecessary, and the construction of an MTB leads to an undesirable weight.

3
  • You are riding in snow, is a drop bar fat bike an option?
    – mattnz
    Nov 20, 2021 at 20:03
  • @mattnz Fascinating. Such beasts (drop bar fat bikes) actually exist. That's nice to know, but still, fat bikes (with either kind of handlebar) is best left for the third picture here: bicycles.stackexchange.com/q/79413/48599 , whereas some bike (of some kind!) that can accommodate studded 29x2.25 (or even 29x2.5 if possible) is best for the first two pictures.
    – Sam
    Nov 28, 2021 at 10:24
  • 1
    Worth reading ... The Practicalities of Turning Your Fat Bike into a 29+
    – mattnz
    Nov 28, 2021 at 21:47

5 Answers 5

9

Another category to search can be "bikepacking bike with drop bars".

Examples I can think about: the Decathlon Riverside Touring 920 (not sure it will be available in North America though), Salsa Cutthroat or Salsa Fargo

These are 29er with 2.4 inches wheels, drop bar and no suspension. As said, these are bikepacking bikes, so designed to be loaded with bags for long offroad adventures. Compared to gravel bikes, the chainring may be smaller (32T, 36T and 40T respectively for the Decathlon, Fargo and Cutthroat), but it may not be a problem in a context in which you need studded tires — and you won't be able to achieve the same kind of speed than with a 40mm tire anyway.

4
  • Great suggestions. I'm starting to have the impression that they still build some bikes like a tank because they don't want to find themselves liable for a good 10% of owners coming back with warranty claims on the frames. Normally we consumers complain of too low standards that enable manufacturers to put awful stuff on the market that'll fail in 13 months, but in this case I hope they would sell some bikes and along with them require the consumers to sign a disclaimer that they do not intend to take their bike to a battlefield.
    – Sam
    Nov 20, 2021 at 15:58
  • 1
    @Sam This category of bikes should be built like tanks because they are meant to be used offroad with luggage, I wouldn't say that the reason is to "avoid warranty claims", but more to have a spec sheet that matches the intended use. They also need to be sturdy to avoid failures when used far away from the civilization (which is, again, the intended use). For example, the Decathlon is rated for a total mass of 170kg (370lbs), while gravel bikes are usually rated at 120kg.
    – Renaud
    Nov 20, 2021 at 16:09
  • Understood. Methinks there is a market for a new category of "snow bike", with a subtitle of "not meant for centennials that'll take you too far from home because there is no place to stop and refueling with fat, not just glucose, using a tube is particularly unpleasant."
    – Sam
    Nov 20, 2021 at 16:10
  • 1
    It rarely gets much attention, but in my opinion the salsa cutthroat is one of the best gravel bikes on the market. If i didn't already have a light/fast hardtail it would be right at the top of my shopping list. Trends in gravel racing are still heading towards larger tyres and some of the faster 2.1/2.2" mtb tyres would make excellent gravel tyres.
    – Andy P
    Nov 22, 2021 at 9:33
5

Is the term "gravel" today already tied to, say, 700c-38, and precludes such a lavish size?

That's definitely not true of most gravel bikes launched in, from my (imperfect memory), 2018 to present. Of course, gravel bikes are a new and evolving market segment. There are gravel bikes out there with clearance for not more than 40mm tires, although they tend to be older. I think that many 2021 gravel bikes probably have 45mm clearance (for 700c tires, more for 650B if they can take that wheel size). I'm pretty sure a significant number will take 50mm tires.

That said, you are asking about a 29"x2.25" tire. 2.25 inches is 57mm. There are definitely bikes that can take 50mm tires, e.g. the 2020 Evil Chamois Hagar (NB, it's apparently designed to take 650B wheels, and you need a 1x drivetrain to use 50mm tires). Some gravel frames may be able to take 57mm 700c tires. However, at this width, the use case is starting to overlap with that of hardtail MTBs, and hardtails are likely to be more capable than gravel bikes on a lot of the terrain where you'd really need a 57mm/2.25" tire. I don't expect a lot of gravel bikes to be able to take this width of tire, although the segment will surely evolve.

The question was later edited to clarify that the OP wants a bike that's capable in snow and ice. I don't have experience with this use case. I believe that riders who frequently tackle those conditions might gravitate towards fat bikes, which have 4-5" tires.

4
  • Nice points. Thanks also for the pointer, even though I was not 🤥 seeking specific product recommendations. I'm still going through the article, but I'll have to remember searching for the sentence 29er mountain bike hardtail with drop bars in the future. It summarizes this (hopeful) category.
    – Sam
    Nov 20, 2021 at 15:30
  • Could you argue just slightly, or provide a pointer, for "you need a 1x drivetrain to use 50mm tires"? Now that I read it, it makes sense and explains the market, but it sounds like you see it as more than just a pursuit of more modern components that avoid FD maintenance.
    – Sam
    Nov 20, 2021 at 16:07
  • 1
    @Sam that was a statement about the Evil bike that was made in the review I linked. In general, though, at some width, the tire will hit the FD cage when it’s in the low position. That width is definitely not 40mm, and probably not even 45mm, but it might be a problem with wider tires than that in general.
    – Weiwen Ng
    Nov 20, 2021 at 16:26
  • 3
    @Sam a 2x would require the chain to be closer to the frame than a 1x. Space is at a premium close to the chainring, if the tires are too big, you'll need to widen the bottom bracket, which would mean to widen the rear axle to keep a correct chainline,... There's a compromise to make, and I imagine that 1x are a good solution.
    – Renaud
    Nov 20, 2021 at 16:28
3

I thought this was quite an interesting question. There are bikes and framesets available to take such big tyres but they are usually for flat bars. If you wanted to build a drop bar gravel bike, you could but with some caveats. I'm using two bikes I'm familiar with to give an example, there are plenty of other choices.

A frameset like the Surly Ogre supports a 2.5" tyre but the sizing scheme is for flat bars so the top-tube is relatively long. However, if you compare the geometry, you can see that, against the Cannondale Slate in a size L, the Ogre size S would give a very similar riding position with drop bars. The main caveats are that the Ogre would need an extra 10cm on the seat post, it would require a mountain crankset (73mm bottom bracket) and the frame triangle would be quite small (for bikepacking bags etc).

See: https://bikeinsights.com/compare?geometries=5b47aef937b53600147a6291,5fbbd9bb132242001755e5a9,

What you want isn't impossible with off-the-shelf components, but you might want to look into having a frame made to your requirements. Depending on the builder it might not be so expensive when you already have a geometry in mind.

2

Possible names for the category of "gravel bike that can accommodate 29″×2.25″ tyres":

1

At least one such bicycle (a gravel bike that can accommodate 2.25" tyres) exists—albeit an exotic one:

https://www.velonews.com/gallery/gallery-ashton-lambies-custom-lauf-seigla-with-2-25in-tires/

(credit for finding it: Andy P)

Lauf Seigla with 2.25in tires

A simpler solution to the problem is to seek the third broad category of mountain bikes. In addition to full suspension and hardtail MTBs, fully rigid mountain bikes exist, and those are (somehow) distinct from hybrid bikes: 1 2 3.

2
  • I expect over the coming years we will see many more examples. Year on year we are still seeing a trend for bigger and bigger tyres on gravel bikes. I also wouldn't consider the lauf to be particularly exotic, the entry level model has relatively modest pricing compared to many competitors
    – Andy P
    May 27 at 14:56
  • @AndyP By "exotic" I was referring to the unusual (unique, likely patented, etc) front suspension. Then of course it becomes necessary to see whether it fails after a bit of use and becomes difficult or impossible to fix. Now I see on their web site that they perhaps expect exactly this kind of suspicion (or maybe of Luddism) and build models without this new suspension.
    – Sam
    May 27 at 15:01

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