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Discussion Starter · #1 ·
So, my lady picked up an old peugeot frame and I'm gonna build it up as a fixie for her. Question is, the frame only excepts a smaller sized wheel. I don't know what size wheels to get for her... I've heard of 650cc wheels, should I be looking at any other odd sized wheels? Anyone know off hand what size wheel this bike accepts?
Thanks. (X-posted in the classics forum)
 

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I can't tell for sure from your picture, but it looks like there's a brake on the fork. Try to measure from the fork slot (about where the center of the axle would be) to about the top edge of the brake pad. Multiply by 2 (to get the approximate bead seat diameter) and convert to millimeters.

If it's a 650C, you should get 571mm.

If 650B (quite possible on older French frame), 584mm.

See this article for more detailed discussion:
http://sheldonbrown.com/tire-sizing.html
 

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fred.r said:
Update.
So, as it turns out, the rear wheel is a 700c, while the front is a 650. Strange, but the bike was designed around it. Thanks for the help.
650c, or 650b? There were a number of women-specific designs that accomodated smaller frames while avoiding excessive toe overlap and the like by using a smaller (usually 650c, I think) front wheel.

If you're building a fixie, and only going to have a front brake, you can avoid the issue of 2 tire sizes by using a small wheel on the back, too. It will change the angles and the geometry slightly, but not drastically. It would slacken the head angle and increase trail slightly, making the bike slighlty more stable.

If you want 2 brakes, that probably won't work, unless you can find a very long reach brake.or a drop-bolt.
 

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Discussion Starter · #6 ·
JCavilia said:
650c, or 650b? There were a number of women-specific designs that accomodated smaller frames while avoiding excessive toe overlap and the like by using a smaller (usually 650c, I think) front wheel.

If you're building a fixie, and only going to have a front brake, you can avoid the issue of 2 tire sizes by using a small wheel on the back, too. It will change the angles and the geometry slightly, but not drastically. It would slacken the head angle and increase trail slightly, making the bike slighlty more stable.

If you want 2 brakes, that probably won't work, unless you can find a very long reach brake.or a drop-bolt.
Yep, building a fixie for her. I already have a 700c on the rear for her, just looking for the 650c front (no where in San Diego has one!). I thought about throwning 2 650c's on it but thought it would throw the geo off too much. But if you're saying it would be a more stable ride with the slacked out angles, I may give it a shot. Thanks for the help.
 

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JCavilia said:
If you're building a fixie, and only going to have a front brake, you can avoid the issue of 2 tire sizes by using a small wheel on the back, too. It will change the angles and the geometry slightly, but not drastically.
Wouldn't that also drop the bottom bracket by about 15mm? :idea:

In a frame that size, she's probably going to be using short cranks, but still, pedal strikes might be a prob.

Could be missing something, but I guess another option, if he can find brakes of the correct reach, would be to just make it into a 650B conversion front and rear. Front gets raised about 6.5mm as compared to 650C, the rear gets dropped 19mm as compared to 700C. Bottom bracket still drops, but not as much... maybe 8-9mm, if my math is decent.

But of course tire availability might be a sticking point, as selection is limited and what 650B tires are out there tend to be fairly fat... the frame might not have enough clearance for any but the 'skinniest' 650B tires (which are still pretty fat).

Still, fatter tires would bring the bottom bracket up higher, and give a nice comfy ride to boot. Guess it depends what you're into.

...
 

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fred.r said:
But if you're saying it would be a more stable ride with the slacked out angles, I may give it a shot. Thanks for the help.
Yeap, he's right, slacker angles make for a more stable bike, but in my experience frames with slack angles tend to be tremendously BORING to ride, too
 
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