cormacf

Never raced cross or ridden mountains. Thought I'd put together a fully-rigid MTB build so I could play at both. I have a full understanding that it won't be particularly awesome at either, but I miss the 26" MTBs of the 80s, so if nothing else, I'll have a fun commute bike I can skip off curbs and go BOING, just like the Stumpjumper i couldn't afford in 1988.

So assuming all these limitations, any particular thoughts on 650b/27.5 vs. 29" for wheel size? I have short legs (30" inseam at 5'10", so I'm leaning toward the smaller wheels, but if there's a massive advantage to larger wheels on cross that someone at middling fitness levels will notice, I'm all ears.

Note: I'm thinking of building up a Lynsket MT27.5 or MT29. The frames are dirt cheap when they blow out their backstock. Thanks!

msu2001la

29" = 700c which is the standard road wheel diameter (and therefore the standard for CX), so if you go with that size, you'll have lots of options on CX specific tires and wheels that you might not find in the other sizes. (Although the rear dropout spacing is usually different between CX and MTB, so just keep that in mind when buying wheels).

From MTB perspective, the difference between 26", 27.5" and 29" seems to be mostly personal preference and isn't necessarily related to your size or inseam. You should have no problem fitting on any of them, assuming you buy the correct sized frame. I'm shorter than you and have no problem on a 29er with suspension for mountain biking.

Doge

Any opinions on a 33mm tire on a 20.5mm width rim?