Hey all. I just picked up an old Peugeot UO-8 that I converted to fixed gear. It's from the early 1970s, and it shows. The bike came with cottered cranks that slip whenever I apply back pressure. I tried to wedge the cotters in tighter with a hammer, then a C-clamp, but no dice. Now I'm looking at replacing the whole bottom-bracket and crank setup with a square-taper BB and cotterless cranks. I've heard about plenty of problems with crank-BB compatibility when keeping the bottom bracket, but are there any problems with out-and-out replacing the whole setup? If there aren't, what size bottom bracket would I get?

French threaded bottom brackets are an odd size, and have RH threading on both sides. Basically, nobody makes them new anymore, except that Phil Wood sells French threaded retainers for their bottom brackets. You have to hunt around on ebay, but stuff shows up there from time to time, or other vintage parts dealers. Velo Orange sells, or used to sell, Edco bottom brackets that are a friction fit that will work with French bottom brackets. Some say you can get the bottom brackets rethreaded, but I would only do that as a last resort.

You may be able to find a spindle that fits into your existing cups with a tapered, non-cottered interface to the cranks. Rivendell sells new tapered spindles, probably others, somebody around here probably knows whether these would work with your existing cups.

Anyhow, a lot of options do exist for this problem.

Thanks for the reply! I have already read about some of those options. But what I'm asking is, is there something different about the metal hole in the bottom of the frame that would prevent me from removing the existing bottom bracket and installing a bottom bracket more suited for accepting square-taper cranks?

Edit: Or by "French-threaded bottom brackets have RH threading on both sides," do you mean that the frame itself has the odd threading in the shell?

the metal hole? you mean the bottom bracket shell? I don't know if you're referring to something else, but the post right above yours just answered all that for you.

Yeah, I was referring to the shell, but I wasn't sure if that was the right word. Anyway, I've figured it out now. Thanks for the replies.

A Stronglight 118mm spindle from the 70's will go right into the existing cups and has ISO taper that fits older French (TA, Stronglight, Nervar) cranks. I had to use a 2mm spacer under the fixed cup to adjust the chainline for a double so it might be just right for a single ring crank for a fixie. I think Campy (pre-92-ish) cranks would work too though I don't know if that would be the right length. I just did that on my UO8 and it worked great. Won't help if you have a Japanese crank but who would use one of them on a French bike anyway?

Velo Orange's Edco French bottom brackets are not a "friction fit", they're French threaded and they're new. They're much too long for a fixie, though. I've found that 115mm is just right for old T.A. road cranks converted for fixie use.

I was talking about another item Chris K. showed me this spring. I was looking for something to fit my Mondia with Swiss threading (and French bb folks think they have problems...) and he showed me an edco that he had that doesn't use the bb threads, but tightens into place by friction. They don't show these on the website currently, but as you note, they do show a dedicated Edco French threaded bb.

You could also keep the cottered crank, remove the outer ring and replace replace the chainring bolts with 5mX10 bolts from the hardware store. If you buy a cotter press from Bikesmith Design and a few cotters, you'll surely end up spending less than you would converting to cotterless. Cottered cranks are cool, especially if they have Simplex adapters and rings. My chainline is dead on with a Formula hub and EAI cog.

i had a hard time with my uo-8 as well. we ended up taking a sawzall to the cotter crank spindle and got it off that way. the stock thin cups were still in good condition, so i used them with an italian bottom bracket spindle and it is all gravy now. im running it fixed with a 109mm bottom bracket on some sugino xd cranks.

oh also if you want a sealed bottom bracket option, there are none...except for a phil wood. or a shimano un-72 with phil wood rings.
phil wood is like 100+, the un72+phil wood rings will cost you about 70 if i remember correctly, but just replacing the spindle and bearings will save you more money.

another option is taking it to get the french threads rethreaded. or the least favorable option, threadless bottom bracket.

That's a gorgeous setup.

I've got a 120 or 119 stronglight spindle on my PX10 fixie, and the chainline is about perfect with a Stronglight crank. I can't recall what I've got on my UO lengthwise; I used Sakae french cups with a Sakae spindle and crank, and it works fine, good line and all that.

Spindle length and taper is almost completely crank dependent, esp. with older cranks, so there's really no good answer.

longish thread from ss/fixed gear on this issue:
https://www.bikeforums.net/showthread...geot+phil+wood