5

I'd like to set up my Surly Ogre for commuting. It currently has 29" 29mm internal width rims, for bikepacking.

I'm thinking of getting a second wheelset for commuting, so it rides less like a tractor. I've been looking at 700c gravel bike wheels or 29" mountain bike wheels, with an internal width around 19mm...

What would be the differences/benefits of these options? They each seem suitable. It seems like I could get either with hub spacing to fit the bike (100m front, 135mm rear). Strength?

I'd probably get a tyre like the WTB Expanse (32mm).

Example of 700c

Thanks

9
  • 3
    Well, a 29" rim is the same diameter as a 700c. (But, of course, a 27" rim has a larger diameter than a 29" one.) Commented Apr 27, 2020 at 0:36
  • 4
    The difference is Marketing, setting expectations and "us and them-isium". MTB originally went 26", and evolved bigger to use wheels, but could not use the same terminology as those disgusting road bikes. Gravel bikes being the "new kid" are and adaption of road bikes, so get 700C wheel, because no way can the use the neanderthal MTB terminology. :)
    – mattnz
    Commented Apr 27, 2020 at 4:44
  • 1
    In my experience swapping wheelsets is too much of a hassle. I always had to adjust the (rim) brakes and shifters because of small differences between the wheels (making it a 15+ minute task). Maybe with disc brakes, identical hubs and cassettes it would work.
    – Michael
    Commented Apr 27, 2020 at 5:31
  • @Michael At races they seem to change spare wheels quite fine. Even from neutral support, so it is not always the same brand. Commented Apr 27, 2020 at 7:29
  • In races it's a choice between having a non optimal wheel for a while and giving up the race. It's a different situation than everyday riding.
    – ojs
    Commented Apr 27, 2020 at 7:43

3 Answers 3

2

You're correct that the difference between a MTB and gravel wheel is strength - and therefore weight.

Presumably you want some wheels that are lighter than the stock ones, so you want to look at road oriented wheels that will take a 32mm tire.

5

As comments to the question state, in terms of wheel diameter alone, 29" and 700c monikers indicate the same rim diameter. Your bike, being Surly, should be able to fit just about anything in terms of wheel diameters and tire widths, up to 27.5"×3.0" (650C) and 29"×2.6" (700c).

However, according to the frame specifications of the latest Ogre model, the frame uses "Gnot-Boost" 145mm spacing for rear wheel. It means it is compatible with through-axle hubs of 142 mm and 148 mm widths, but not with 135 mm ones with quick release. There are adapter washers for QR wheels from Surly to accommodate for QR hubs, so it should be possible to use such wheels. I think you might also have to adjust the rear disc brake caliper position when axle type is changed, but that is usually required anyway at wheel swaps.

The bike does not have a front derailleur by default, but if you use one, the specifications page mention that you will have to use different derailleur offset adapters to keep optimal chainline.

1

For a "non-boost" bike, the main difference will indeed be the strength, but I'd also add the freehub body: a gravel wheel, deriving from road standards, will very likely come with an 11-speed/36.85mm road spline or an XDR spline. MTBs wheels on the the side will come with the standard 35mm spline, an XD spline or a Shimano Microspline (more details here).

No problem to use road splines with MTB cassettes or road cassettes with the largest cog that is equal or bigger than 34T, as only a 1.85mm spacer is required to use these cassettes on road spline. But that can be an issue the other way around: road cassettes with a largest cog that has less than 34 requires the road spline. The limit of 34T only applies to Shimano splines, with XD and XDR, only a spacer is also required to fit an XD cassette on a XDR spline, but I'm not aware whether there are road cassettes that are compatible with XD splines.

(Shimano Microspline is still very confidential on road/gravel bikes, but is also very confidential on 135mm MTB wheels, but it's something to keep in mind - Microspline is only compatible with 12-speed cassettes).

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.