26" fenders on 650B wheels?
 

I am getting together the parts to build a 650B wheelset. I've got the hubs, some Weinmann rims, and will get a set of Panaracer Col de la Vie 38mm tires. I'll spring for the VO 650B fenders if necessary, but I was wondering if 26" fenders would work, because they're cheap and available locally.

I have 26" Planet Bike plastic fenders on my bike with 650b.

I've done that as well, with SKS p50 fenders. 26" fenders are still designed to cover a 26" rim- fitted with a fairly wide tire. So if you think about it, the outside wheel dimensions of a 650b rim fitted with, say- a 34mm tire (like the Nifty Swifty), aren't much different from a 26" rim fitted with a fatter 1 3/4" or 2" tire.

You could make it work with plastic fenders, they're flexible enough. I'd get the exact size/radius if I were installing metal fenders.

For 38mm tires, you want a minimum of 45mm wide fenders. I use 45mm SKS P45 longboards over Grand Bois 650b 38mm tires on my Rivendell, and they fit just about perfectly. They're made for 700c tires, so they are a little long (good for spray coverage). the 26" fenders would probably be a little short on 650b wheels.

What do you mean by 26" fenders?

In general, you can take a fender for a small fat tire and make it fit a thinner tire with a larger diameter; and you can do the opposite, making a larger diameter fender for a skinny tire fit a smaller diameter but fatter tire. A fender that fits nicely over 700 x 32 c tires will fit nicely over 650 x 35 c.

I generally agree... as mentioned before, you can get away with running 26" MTB fenders IF you plan on using skinny tires. If you want to run fat tires, like the Grand Bois or something, you'll definitely want either an actual 650b fender, or make the outside wheel calculation and see if a fender designed for 700c will be a better match.

How about putting 650B fenders on 26" wheels? I am considering putting the 650b Velo-Orange Zeppelin 52mm Al fenders on 26" wheels mounting 44mm (actually 42mm fully inflated) slick tires. Do you think the profile/fender line will be acceptable?

That's what I did on my commuter bike, but with 50mm x 650b Berthoud fenders and 38mm x26 tires. They fit perfectly. And if yours don't, metal fenders can be (gently) massaged to fit slightly larger or smaller wheels.