Made by Mark Nobilette and designed by Grant Peterson, my 650B Protovelo is a lot of fun to ride. I’ve had it set up as a city bike and as an all-rounder with drop bars, but I’ve always wanted to try the Grand Bois Hetre tires. Like a lot of bikes made before last year, it was optimized for 38mm tires, so the Hetres, coming it at 42mm, are a tight fit with fenders, especially at the seatstay bridge:
I am not a parts snob by any means, but I must say that these tires are the best I’ve ever ridden. It kind of feels like they’re not there. Like you’re floating along. And what better way is there to amble through the city or along a nice country backroad…
The 50mm Honjos I had on the bike were a bit tighter than I was comfortable with. I added 50mm Berthouds in order to better accommodate the Hetres. I tried to document the clearance with these mudguards:
“For many bikes using the Grand Bois 650b x 42 Hetre tire, the 650b x 50mm Berthoud fender is the best fender option available. The reason is more luck than intent we believe. The Berthoud fender in this size has a relatively flat profile – so it doesn’t wrap as far down alongside the fender as some of the traditional French fenders that are not easily obtainable. So the result is that the fender needs less clearance.”
I found that there was a bit more room with the Berthouds, but they are more stretchy than the Honjos. When I first mounted the rear fender, I drilled the hole for the seatstay bridge a bit off, and it stretched out the fender. When that happened, it became slightly more narrow.
I think 650B bicycles look “right” with mudguards, especially ones in larger sizes. It all depends on clearance.