650 wheels on a cross bike?

[lunacycles]

I've never seen a 650B tire appropriate for CX. That doesn't mean there isn't one, but 650B availability is less than any other size I know of, and I've never seen one with a tread pattern suitable for CX.

Disc Brakes are not legal for CX racing, last time I checked.

Martian Destiny:
Why do you assume 26" equals "mountain wheels?" What does that mean?
You can easily build a very nice, responsive, and well-fitting CX frame that will accommodate 650c (road) and 26" wheels--I do this all the time. It wouldn't have to resemble a "hardtail" in the slightest. 26" wheels don't need to be "mountain wheels." Go with a light velocity rim and 130mm road hub of your choice, double butted spokes...handbuilt and very sweet. My 26" CX wheels are the sweetest wheels I own, and lightest. There are also excellent, light, kevlar beaded 1 inch slicks (25c) that come in 26". If you are going custom you are welcome and usually invited/encouraged to think outside the box a bit.

Honestly, possibly the best advice I have: listen to whatever framebuilder you've chosen advises. If you trust the builder and they are experienced and know how to make a bike that really fits, s/he will take care of you.

[MartianDestiny]

Honestly, possibly the best advice I have: listen to whatever framebuilder you've chosen advises. If you trust the builder and they are experienced and know how to make a bike that really fits, s/he will take care of you.

This is potentially my snag. I trust and highly respect my fitter/shop owner. The builder, while I know they make good bikes, is just simply the builder he uses (so I'm trusting them only by default). So, while I know they'll make me a bike that fits and that I love (because I trust my fitter when he says they will) I honestly don't know how many tiny bikes they typically build. (or how many customs for that matter as this is a production bike company with a small local custom side). And well, I'm kinda used to being my own best advocate and knowing exactly what compromises I'm making and that they are the compromises *I* want (because I'm generally not the typical small rider in build or mindset).

For instance I had no idea I could design a bike to run 26" "mountain" wheels (with a road hub I suppose) and 650 "road" wheels. The builder (when they get back to us this week) may indeed bring that up, but I like to know these things ahead of time

I think I'd be ok with running a 26" wheel for cyclocross so long as I could convert to a 650 road wheel relatively easily for road use, which it sounds like I can. (I'll be perfectly honest, I think 26" tires look ridiculous on road bikes even in my size and I'm vain. Plus I don't want to run into the same issue of tire availability trying to find a slick that isn't 2.0 and designed for a commuter).

I won't be running disks for races, but the bike will have disk mounts (if I have anything to say about it ). I honestly don't know if I'm going to race past this season, so I want to be able to put some reasonable brakes on it for general trail and road use. I like stopping

Thanks for the input! It's been very helpful and informative. Being the researcher I am, I guess I'm not really letting the builder do his job

My fitter did say he'd arm-wrestle me over the 700 issue, AFTER he said I had the most developed shoulder/back muscles he's ever seen, LOL. Apparently I'm a freak of nature.