Teach me about my rim/tire options w/ canti brakes

[hoj]

Alright, so I bought a caad x (2012 frame w/ cantilever brakes) that is now my primary commuter bike. I love the bike so far and have had a lot of fun exploring some of the trails out here in NC.

Since it's my commuter though, I'm looking to replace the cx tires currently on it w/ something a little more road-friendly. I've been thinking it would be fun to try out a "road-plus" tire option, such as the WTB Horizon (650b) or maybe something like the Maxxis Re-Fuse (700x40).

WTB Horizon: http://www.wtb.com/collections/road-plus

Maxxis Re-Fuse: http://www.maxxis.com/catalog/tire-511-re-fuse

Since the bike is running cantilever brakes, is it even possible to run a rim size other than 700c? AKA, is there any possible way to actually get the WTB Horizon tire on my bike (assuming I had wheels to fit the tire, etc.)?

With regards to the Maxxis Re-Fuse tires which are 700x40, if I've already got a set of ultegra 6800 rims (700c), would it be possible to run a tire that large on this particular rim? Or is that a really bad idea? What's the biggest tire I could [safely] run on the ultegra wheels?

[nash]

650b - no

Tires - as big as will fit in the frame. No safety issue at those relatively small widths.

[jtbadge]

650b - no

Tires - as big as will fit in the frame. No safety issue at those relatively small widths.

+1. Wider tires will ride better on wider rims, generally, but you should be totally fine.

I'd love to hear some reviews of the 40c Refuse, if anyone here is riding them yet.

[Peter P.]

Neither tire will fit your 'cross bike.

You need a 700c tire restricted to typical 'cross tire widths. Of course, you'll have to try them, but typically you're limited to 35mm maximum tire width.

What you're asking for is a dedicated 650b bike (your cantilevers won't adjust to fit the rim) or a 700c "monstercross" bike which can accept tires much wider than the 35mm restriction mentioned above but varies by manufacturer.

[Benneke]

Check the tire clearance on the CAADX before you buy anything wider than 35mm, many CX bikes can't fit 40mm tires