650b on a road bike?

[Chicken Chaser]

I'm not really planning on doing so, but something that came up in a recent conversation that I wasn't sure about.

Provided that a bike has good clearances and has disc brakes, will it be compatible to run 700 and 650b wheelsets? What makes a bike 650b compatible?

Also for those that use 650b on a road bike, what's the benefit? I've done xc single-track on 700x35c tyres and found it manageable, the only thing that I missed was some suspension travel, and I had what felt like more pace as a substitute.

[m444ttb]

I think the answer depends on why you would run 650b. if it's for gravel and therefore you have a larger tyre then the wheel/tyre diameter with the tyre on would be broadly the same. If it's because you're small (e.g. women on the shorter side) then it'll change the geometry of the bike I think. If the frame correctly accommodates 650b wheels for either of the above they do seem like a good idea.

[PGM]

I run a 650b wheelset on the Pickenflick Ti CX frame, also a 700c

Great fun running low tyre pressures in MTB sportive events like the Chilterns Watlington and blowing away full suss riders on the descents!

Edited by PGM on Tuesday 3rd April 14:56

[The_Jackal]

PGM said:

I run a 650b wheelset on the Pickenflick Ti CX frame, also a 700c

Great fun running low tyre pressures in MTB sportive events like the Chilterns Watlington and blowing away full suss riders on the descents!

Edited by PGM on Tuesday 3rd April 14:56

I think that says more about the talent (or not) of the riders than the equipment.

[waynecyclist]

I built a coyote roadrat for someone once, as standard it is built for 700c but he wanted 26" wheels to match his other bikes.

It worked but was very tight for crank to road clearance plus mudguards needed spacing down.

He still has it and has done around 5000miles so it must be ok.

[alfabadass]

It's a trend with some bikes.

650b wheels but with 42mm tyres for more comfort.

[lufbramatt]

Didn't cannondale used to do this when disc brakes first started becoming popular? some bikes came with 2 sets of wheels so you could convert your MTB to a hybrid.

[PGM]

The_Jackal said:

PGM said:

I run a 650b wheelset on the Pickenflick Ti CX frame, also a 700c

Great fun running low tyre pressures in MTB sportive events like the Chilterns Watlington and blowing away full suss riders on the descents!

Edited by PGM on Tuesday 3rd April 14:56

I think that says more about the talent (or not) of the riders than the equipment.

It does, yes, I have a full suss too for when it gets very technical like rocky descents in the Peak District and for rough bikepacking. It's highly amusing though, new area of fun for me!

[louiebaby]

PGM said:

I run a 650b wheelset on the Pickenflick Ti CX frame, also a 700c

Great fun running low tyre pressures in MTB sportive events like the Chilterns Watlington and blowing away full suss riders on the descents!

I was about to say there is a chap in here who has both sets built on the same hub, so can swap in minutes, but you beat me too it.

I might have taken notice for the future, but mainly for the kids when they're a bit older.

[TwistingMyMelon]

Shirley 29er wheels would be a better option, less likely to get fit issues?

Edited by TwistingMyMelon on Wednesday 4th April 15:23

[PGM]

My two sets, the 650b with 50mm tyres are close in overall diameter to my 700c with 33c tyres so the geometry and sizing are not noticable between them.

I use the 650 set for general off road touring and MTB stuff like singletrack in the Chilterns and the 700c set for CX racing, the regs are set for tyre width there and would be faster than the 650 in that environment.