650A to 700C Conversion?
 

Hey everyone. My girlfriend has a mixte that is currently running 650A rims with fat tires and fenders. What's actually important for her though is that the bike is easy to use, and light because she lives on the third floor of a complex with no elevator.

Thusly I've made the determination that 700C wheels will be a big improvement--easier keeping a straight line, faster, longer coasting, MUCH larger availability of types of rims, tires, hubs. She just don't commute by cycling when it's raining anyway, and the fenders just add too much weight for her.

Will this conversion work?

I don't think they fit, esp the rear wheel. You can fit MTB 26x1.75 wheels on most 650A frames, lots of skinny rims/tubes available. I'd sell that bike and buy her a nice 700C hybrid/cross on CL.

I'd build up some new wheels with Sun CR-18 aluminum rims in ISO590 (a.k.a. 26 x 1 3/8 a.k.a. 650A) and mount some Col de la Vies, that way I wouldn't change the height or geometry of the bike or need a new fork or brakes. But that's just me; knock yourself out. With thin 700C tires the diameter is almost a wash.

622 + 23 +23 = 668

590 + 37 + 37 = 664

700C hubs?

tcs

It might. I suspect it will. You might need new brakes, but I'm sure someone has a used set you can have cheap (I do).

Worth it? I don't know about that, I kinda like that bike the way it is, but it's your call.

I converted this Rudge from 650A to 700c with 35mm Pasela tires, but it involved installing a new front fork. The original fork was spaced for a 90mm hub and I didn't think it would have the clearance for 700 x 35--the new one does but no room for fenders.

http://web.mit.edu/nlerner/Public/Bi...dgeBendix1.jpg

Neal

thanks everyone, that's exactly what i was looking for.

@mr IGH
she really likes the aesthetics of that frameset, which is why we are working with it. otherwise if she really wants light, i'd just build her an aluminum frame track bike with an internal hub to fullfill her basic climbing needs haha. that's why i have to cut weight through roundabout means like removing fenders and getting smaller tires haha. a steel mixte is never going to be light.


@tcs
haha yeah 700c-specific hubs. they exist at 330AM --". in my head was a vague notion of factory made wheelsets.

@nlerner
a picture's worth a thousand words! thanks a lot. i was expecting that i would need to buy a new fork, but not for the reason of spacing.



-D

Just so you know, a good selection of 26 X 1 3/8 (ISO37x590) tires are available. A charge card will get you any of these either in your hands or on order today:

Bell Sports Streetster (folding)
Chengshin C638
Continental City Ride
Kenda gumwall
Kenda Cross (knobby)
Kenda K40 Street
Michelin World Tour
Nutrak Traditional
Nu-teck (airless)
Panaracer Col de Vie
Panaracer ST Daily Commuting
Pyramid gumwall
Pyramid Sunlite Hybrid Nimbus
Raleigh Record
Rubena Flash V66
Schwalbe Delta Cruiser
Schwalbe Marathon
Schwalbe Marathon Plus
Schwalbe Speedway Pro (knobby)
Specialized TriSport
Vredestein Perfect Tour

tcs

Am I only one who thinks the front-end geometry of that bike looks funny? That head tube looks really steep. Maybe it's just the angle.
-Gene-

I'm guessing that those are steel rims on the bike now. If so, Sun CR-18 alloy 650A rims weigh (slightly) less than the corresponding 700c rims. Panaracer Col de la Vie (available in 650A as well as 650B) weigh about 390 g, which is reasonably light. Going in this direction would be easier, not require a fork swap. In addition, dropping down to 23's might be uncomfortable for her. I wouldn't be surprised if the bottom bracket/crank and the cluster offered greater opportunities for weight reduction.

@Amani546. Your comment about the head tube reminded me. The fork that is on the bike now has quite a curve to it. Does anyone know whether that poses particular issues with readily available replacement forks?

Why would you want to replace the fork?