Reading this article on Pinkbike set me off thinking

http://www.pinkbike.com/news/foes-mixer-trail-review-2016.html

The one thing that niggles about my current bike (a Whyte T129) is the well documented rear tyre clearance.

Now if I were to stick a 650b rear wheel in then I might be able to run a wider tyre which once winter is past will be a bonus.

So is anyone running a 29er with a 650b rear wheel at the moment? Anything good or bad coming from it?

From last year…
http://unduro.co.uk/mtb/behold-the-frankenthumper-aka-project-279/

It was great, only real downside was slightly reduced rollover. How high is your bike’s BB now?

I know nothing about the pro’s and cons despite having owned a specialised big hit with 26″ front 24″ rear. I could never tell any difference.

One problem you may have is that a lot of frames bulge out specifically where the tyre is going to sit. Your new tyre although smaller in diameter may clash with the frame.
An example is shown on the photo below. Note where the chainstay is thinned on the drive side but bulges back out further away from the bb.

I’m not saying it isn’t possible as all frames are different but just check before buying anything.

Edit: here is an extreme example that shows what I mean better. You dont see many (if any) like this any more though.

Seemed to work for the Liteville here. I find it weird that the bike somehow looks “right” to my eyes despite the mismatched wheels.

Editors’ Choice – Jamie’s Picks of The Year

Built this 3 or 4 years ago, (before liteville) 29er front 27.5″ rear and a 2011 trek remedy 26″ frame, shock was machined 20mm shorter eye to eye to drop bb and slacken headangle (alot)

[url=https://flic.kr/p/hyF77W]photo 2[/url] by Loco Tuning, on Flickr

edit picture looks compressed tbh, that a 21.5 ” frame :-/

Further to my comments above I didn’t put two & two together when I read Whyte T129.
I did some work on my neighbours nearly new T129 and the tyre clearance was non existent on one side. This wasn’t helped by the fact that the rear wheel was dished to one side and had a some point slightly rubbed the paint off the frame. I advised him to go and get the wheel re-dished to suit which he did and the whyte dealer said they had a quite a few whites with this problem. Tyre clearance is now better but still pretty rubbish.

Good stuff all and a few things to look at.

In terms of specifics I’d need to measure the chainstay yoke but from memory it’s not a bad as the picture linked above.

I did try an old set of wheels with extra dish added to the non drive side which improved it a little but it was still very close and I haven;t yet done it to my current wheels.

I believe the bottom bracket is fairly low and I’ve already switched to 170mm cranks from the 175mm fitted before so I guess there will be more chance of pedal strikes.

I guess I really need to borrow a back wheel and fit it to see how things go.

When I was riding a lot in BC, about 10+ years ago, some of my crazy Canuck riding buddies were using a 24″ rear wheel. It was silly steep dh riding, most of it by fall line and their take on it then was it helped to balance the bike. Nothing new really

The lower BB was amazing for steep stuff when I did the 279er thing.

Sounds like a good idea to me