Utility Cycling - 700c bike with 26" xtracycle?

I have a Gary Fisher 229 that takes 700c wheels and I'd like to put an xtracycle on, but I've heard that the 700c version of the free-radical won't work with wider tires. So... can I use the 26" version on a frame meant for 700c wheels? I have a karate monkey fork on it, and the thought of a 69er xtracycle with fatties has me all excited...

You can use a 26" wheel on a 700c frame if you don't use rim brakes and your bottom bracket is high enough. I run an xtracycle on a karate monkey with cliffhanger 26" rims and Big apple tyres. It is wonderful. As for running the xtracycle with 700c, I could only manage to get 32mm tyres in it with a (little) room left for fenders. It works. Not ideal but it works.

HTH

I would ideally use a 700c wheel in the front with a smaller tire and a 26" wheel with a fat tire in the rear. That way I could use front and rear rim brakes, but I'm worried that the trailer would tilt back.

The only difference between the 26" and 700c versions is the brake mount location. So yeah, the 26" version should work fine with a 700c bike.

(this is all stuff I've read on the xtracycle site/forums, not first-hand experience, so it might be prudent to triple check)

with the long wheelbase, your bike won't be tilted backward very much... but it will be tilted backward a tiny bit. If you ask me, it's nothing worth worrying about. There's nothing particularly bad about a bike with two different wheel sizes.

If you have a non-rim brake up front, you have the choice to go dual 26" wheels and have the axle heights match (so you'll have a non tilted bike).

Cool, thanks. Now if only QBP had them in stock...