I converted my Rivendell to 650b wheels, in order to gain more clearance so that I might run fatter tires with fenders. 650b is 584mm circumference, whereas 700C is 622mm circumference. A 650bx42mm tire is roughly the same circumference as a 700Cx23 tire.
My Riv is a full custom that was originally designed around 700Cx28 wheels and tires. It did not have enough clearance for fenders that way. With the change to 650b I am able to run 38mm tires and I have installed SKS P45 Longboard fenders.
Parts required for the change:
650b wheelset
650b tires
650b tubes
Tektro R559 ultra long reach caliper brakes (55-73mm reach) - these are necessary because the braking surface is 19mm lower with the smaller rims.
Other parts changed:
I had a Campagnolo rear wheel before, but my 650b wheel is Shimano. So I bought a new Shimano 9speed casette and 9 speed Dura-Ace bar end shifters. Still using the Campy derailers though, which by the way work fine.
I bought a new Sugino XD600 crankset with 170mm crankarms, also. I was running 180s before as I am very tall, but the bike already had a fairly low bottom bracket with the 700c wheels and I just lowered it somewhat, and I was worried about pedal strikes.
Results:
I love it! Have done several 200Ks, a 300K and a 400K with the bike like this and several of the rides have been in rainy conditions. The fenders really make the difference between getting just a little wet or being totally wet plus covered in road grime. My drivetrain also seems to stay cleaner with the fenders.
The bike already rode pretty well with the 700x28 being a lugged steel bike in the classic style, but with the lightweight Pacenti Pari-Moto 650Bx38mm tire I am running, the ride is totally sublime. Chip seal is hardly even noticeable anymore.
On the downside, I did have one pedal strike going around a right hand corner one time. And the lightweight (290 gram) 38mm tires I am running are a bit fragile, and they are costly at $60 each. But neither of those things have really deterred me
So anyway, if you have a classic bike, or a newer bike in the classic style like my Rivendell, this may be something that interests you.
My Riv is a full custom that was originally designed around 700Cx28 wheels and tires. It did not have enough clearance for fenders that way. With the change to 650b I am able to run 38mm tires and I have installed SKS P45 Longboard fenders.
Parts required for the change:
650b wheelset
650b tires
650b tubes
Tektro R559 ultra long reach caliper brakes (55-73mm reach) - these are necessary because the braking surface is 19mm lower with the smaller rims.
Other parts changed:
I had a Campagnolo rear wheel before, but my 650b wheel is Shimano. So I bought a new Shimano 9speed casette and 9 speed Dura-Ace bar end shifters. Still using the Campy derailers though, which by the way work fine.
I bought a new Sugino XD600 crankset with 170mm crankarms, also. I was running 180s before as I am very tall, but the bike already had a fairly low bottom bracket with the 700c wheels and I just lowered it somewhat, and I was worried about pedal strikes.
Results:
I love it! Have done several 200Ks, a 300K and a 400K with the bike like this and several of the rides have been in rainy conditions. The fenders really make the difference between getting just a little wet or being totally wet plus covered in road grime. My drivetrain also seems to stay cleaner with the fenders.
The bike already rode pretty well with the 700x28 being a lugged steel bike in the classic style, but with the lightweight Pacenti Pari-Moto 650Bx38mm tire I am running, the ride is totally sublime. Chip seal is hardly even noticeable anymore.
On the downside, I did have one pedal strike going around a right hand corner one time. And the lightweight (290 gram) 38mm tires I am running are a bit fragile, and they are costly at $60 each. But neither of those things have really deterred me
So anyway, if you have a classic bike, or a newer bike in the classic style like my Rivendell, this may be something that interests you.