650b conversion

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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
smile.gif


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.
 
Rivendell's are GORGEOUS. Hopefully there will be room for one someday in my budget (and before I become too old/fat...)!

It's neat the choices in wheel size we have now. One of my cousins is trying to convince me to go to 29" on the MTB, but that would mean a new fork, I'd have to redo the brakes, $$$... sounds like it worked out well for your roadie!

And yeah, pics please ^_^
 
Thanks for sharing.
I have few remarks.
1. As already mentioned 170mm cranks are short for your length, but who cares – track bikes are also running with shorter cranks.
2. Brake performance seems to be affected by such changes. However the old brakes ware also bad compare to latest shimano brakes generations.

Tires –have you look at Schwalbe bands. I’m using Marathon racer evolution and performance line. For mixed/on/off road they offer Mondial and Supreme. Most likely they have 650 size too.
The new marathon Allmotion will be available soon in Europe – most likely in US too
 
Originally Posted By: miro
As already mentioned 170mm cranks are short for your length, but who cares – track bikes are also running with shorter cranks.


Yes, I remember when 165mm cranks were the standard for match sprinters/maybe even kilo riders, regardless of their femur length.
wink.gif
 
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