chintanjadwani

Hi, I have a beginner question.

I was trying to understand how different wheel sizes can be made to fit on a 26" bike. A 26x 2.5" wheel will have a wheel length of 686mm and a circumference of 2155.13. Assuming this wheel fits, and if the bike can take disc brakes, can this wheel be replaced with a 700cx32mm which has the same length and circumference or a 650bx2.0" that has a length of 685.60 and circumference of 2153.88?

I read that the wheel sizes shouldn't be changed due to changes in the bottom bracket height and due to the geometry, I'm not able to follow how (and if it) matters if the eventual wheel length remains the same.

Sorry if this has been answered elsewhere, I couldn't find it - you can share the link if it has.

Thank you

veganbikes

Well it would be important to know your plans here and why the want to switch to a different tire size? Personally these days I generally want the widest tire I can get within limits. There are some 26" road tires or at least smoother slicker stuff.

Usually the BB height issues are more important when going down in sizing.

chintanjadwani

No plans, just curious

veganbikes

Yeah I guess you could do it but no real useful point. A wider tire is going to be better for mountain biking. Sure maybe a 29er does roll over things better but I still would prefer to have a smaller wheel and the wider tire for added comfort and stability and more tread on the ground.

theblackbullet

this is a 26" to 700c conversion. I can run 26x2.3 or 700x38. The 700x38 has the bike sitting taller. This is simple for a disc brake bike, however if you're still using rim brakes, you will need to source brakes that enough adjustment to reach the 700c brake track.

700x38

26x2.3

CliffordK

It may or may not work. It will depend on the bike.

A while ago I bought an old Litespeed Titanium MTB frame that I decided to convert to a road bike.

Unfortunately BikeForums deleted my old photos. But, here is a photo I was able to scrounge up.



Anyway, the frame came to me without a fork, so it was built up with a road fork.

I've got 700x25 tires on it. Although I might be able to get slightly larger tires on it.

The whole thing works, but isn't quite optimal.

You can see the canti brake posts on the rear are obviously in the wrong place. So, it got an older center-pull brake that could take the original cable stop.

The biggest thing is that it had a very wide Q-Factor on the crankset. And the large chainring just barely cleared the frame (maybe).

The frame was low and long. But, perhaps not too bad to try something different.

Of course this isn't designing a MTB/Gravel bike. But, going to a road style.

crowbike

2001 26" Homegrown converted to 27.5 x 2.00. Have also used it to race cyclocross with 700c x38. No real profound effect to the handling due to higher bottom bracket. It does help minimize pedal strikes. I've been riding this setup since Pacenti first introduced 650b mtb tires.

scubaman

If the net wheel diameter is the same, and you’re using disc brakes, it’ll work fine. For rim brakes, you might be able to find cantilever or V/linear-pull brakes with enough adjustment that you can go up a wheel size, but that’s more of a varsity-level modification, including because raising the brake pads will change how the brake performs.