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Old 10-26-10, 09:42 PM   #1
mrmouse12
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replacing a fork on a french bike?

hi

so i recently had a spill everything fine except the front fork, which bent and i feel i shouldn't just try to bend it back fearing it braking and me getting injured again.
i have a peugeot ao-8.
i was wondering if its possible to replace my bent fork with a non french fork. As long as its all the same sizes and i get a headset that fits onto that fork.

is there anything i could be overlooking?
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Old 10-27-10, 02:42 AM   #2
mr.smith.pdx
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You may have trouble finding a fork that is not french that is the same size.

the french like to engineer everything their own way. I'd say find another french fork. Preferably, same manufacturer. Or, learn how to read calipers and or a micrometer. You might need to do that with another french fork anyway.

You should also ask this in classic and vintage. Those guys are wicked smaht.
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Old 10-27-10, 07:55 AM   #3
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You don't have to use a French fork, but you will need a new headset and stem if you don't. Your handlebars probably won't fit a non-French stem.
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Old 10-27-10, 08:03 AM   #4
ArthurIhde
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The size is the first
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Old 10-27-10, 11:02 AM   #5
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If you replace the fork with something new, you will end up also replacing the headset because the threaded portions are different on French bikes of that era (25x1 vs 25.4x24tpi). The stem will also need to be replaced because most French bikes used a stem quill/steerer that was 22.0mm and modern quill stems are normally 22.2.
If the fork blades are not kinked, the fork probably can be re-straightened. Maybe a local framebuilder can be of assistance?
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Old 10-27-10, 11:31 AM   #6
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Yup, metric FRENCH fork specs 22mmID & 25mmOD lost out to the fractional system, in the world market.

so 1'' forks with 7/8'' ID are where new replacements will be found.

25.4 & 22.2 are metric equivalents of fractional inch sizes.
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Old 10-27-10, 04:08 PM   #7
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indeed, you'll need either a NOS french fork that'll match your geo needs, or you'll need a ISO fork that'll match your geo needs AND an ISO threaded headset. Lucky that the headtubes of old peugeots take either headset's cups, but that is where the similarity ends. The TPI, stem diameter, and crown race diameter all differ between ISO and the ol' french standard.

if you can't find an old french road fork, pm me. i might be able to help.

-rob
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Old 10-27-10, 04:26 PM   #8
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Quote:
Originally Posted by mrmouse12 View Post
hi

so i recently had a spill everything fine except the front fork, which bent and i feel i shouldn't just try to bend it back fearing it braking and me getting injured again.
i have a peugeot ao-8.
i was wondering if its possible to replace my bent fork with a non french fork. As long as its all the same sizes and i get a headset that fits onto that fork.

is there anything i could be overlooking?
An exact replacement will be hard to get, but there were a lot of UO-8s and AO-8s made and imported here. A new near-replacement will be hard, but easier. The bike will handle differently.

The AO-8 forks are made of steel that can with care be bent a few times before it weakens. It's mild carbon steel, less strong but more ductile than chrome-moly or similar (501, tange anything, 531, Columbus SL, or anything better than those). Find an old LBS and a senior or just plain good mechanic, and explain you want to try to resurrect this old one. Not sure of the right labor charge, but a new-made fork will be a lot more than that.

Last edited by Road Fan; 10-27-10 at 04:29 PM.
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