650b wheels in a 29er frame

So, I have a Niner air 9 carbon frame, sic xx carbon forks, single speed.

I am thinking / wondering about popping some 650b wheels on it, likely CK on Enve carbons.

I want a light / fast / manoeuvrable bike for xc racing type riding.

Now, I know people are going to say that 29er frames are built for 29er wheels, and that I will get loads of pedal strikes.

But…

Has anybody actually tried this out themselves? Is it a really bad idea, does it actually work ok, is it fantastic?

Just thinking out loud, and inviting comments.

Thanks in advance.

All the stuff you said we would say. Very expensive experiment.

I’d certainly try it but I’d expect the results to be a bit mediocre. You get pedal strikes with some bikes but they’re a side-product of having a coherent design around a low bb, giving advantages elsewhere in how the bike rides.
Dropping the bb nearly an inch on your 29er just like that, with no method of compensating for this sounds like a way of inferiorising your ride. How much it really makes a difference I’d be interested to hear.

If you’re talking about racing I guess it’s more worth doing because who gives a fk about a sub-optimal bb height when your pulse is at 180 for 2 hrs? The light wheels may be more relevant there.

inferiorising your ride

Exsqueeze me. I’m sorry, did I stumble upon a bike industry marketing meeting? ‘Inferiorising’. Nice. Up there with ‘leveraging’.

Thinking about the BB height some more – there is a 1.5 inch, or ~38 mm difference in wheel size, halve that and you have a 19 mm difference in BB height. 19 mm doesn’t sound much to me. The height of tyres varies quite a bit and so with a “taller” tyre some of that difference could be accounted for. On top of that, using new or only slightly worn tyres will help to maintain the height, as tread depth is likely 5-10 mm., a worn tyre further lowers the BB height. I normally run 180 mm cranks on my other single speed, but this time I am going to 175 mm as per all my other bikes. I am now doubting how big a problem the lower BB height may be now – as I really can’t recall having many pedal strikes – apart from when I ride in silly gullies – which could be avoided.

Well, I can fit 29” wheels into my 650b frame… interesting results.

Ska-49 – care to elaborate, please…?

I have said someone should try it, but more for a wet/mud set up as a lot of 29″have poor mud clearance.
tey and borrow some wheels and see if it works

Bump for the morning shift

29 front 650 rear maybe, that’s what I’ve fitted to a 2011 Trek Remedy

😉

Hey loco – thanks for the post. Would you mind commenting on the ride difference please?

Never rode it with 26″, however have ridden smaller a 19.5″ remedy (this is a 21.5)
Rear shock is shorter eye to eye and stroke to adjust bb to reasonable height, forks are 130 adjusted revs solo airs ( rct3), again to keep bb lower and not make it silly slack, other than that all pretty standard kit 45mm stem with 5 degree rise run upside down and 750 bars.
It is incredibly stable and very fast downhill, the front end is still pretty slack at 66 ish which alot on a 29er but short stem and still fairly high bb 14″ unsagged/loaded mean it does ‘tip in ‘ quite well when lent over it’s incredibly stable and generates a silly amount of grip.
Shocks and other stuff will be adjusted overtime to tweak the geometry