Okay. So I'm in the process of converting my U08 into a fixed gear town bike and the bottom bracket thing is killing me. Does anyone know what size spindle will fit into the cups on the bb so I can run a different crankset. My cranks still spin smooth and true and have almost no play, but I'm leery to take the cotter pins out and disect the thing if I won't be able to get it back together properly or if it won't do any good.

Any suggestions?

You could use the existing crank, just take one of the chainrings off. If you want to change the crank to a square-taper crank you will need to take the BB apart. It's french so both sides are right hand thread. To replace the spindle, probably the best approach is to get a set of Sugino french threaded cubs. Then you can use the relatively common Series 3 spindles. A series 5 spindle will fit with the existing cups, but series 5 spindles are almost non-existent.

i've researched this extensively (thanks sheldon) and i appreciate the reply. do you know if those sugino cups are readily available?

I found French-thread Sugino cups about a decade ago, but they are getting harder to find every year. You may want to consider using two adjustable cups instead of one fixed and one adjustable, so that you can fine-tune your chainline.

Damn! That is a brilliant idea. I have soooo many French bikes and that never had occurred to me.

You're my new Hero!

I suspect your cranks are the common 3-arm style. These had a bolt circle diameter of 116 mm and this was virtually an industry standard for many decades. And, 3-bolt chainrings between brands were typically compatible and interchangeable. You might easily be able to find good chainrings in 42t or 48t sizes if you could work your rear cog around those gear options. If so, you could simply remove one chainring (and possible a tacky outer chainguard ring) and just use a single ring on the bike - just left basically as is.

Also, if you can find a square tapered spindle of a suitable length, you may also be able to still continue to use the existing cups. Manufacturers were always happy to go with their cheapest options and minimizing their parts stockpiles. So, the cups may be virtually identical with cotterless cups - even on the insides. In my experience there was often adequate clearance in the axle holes of the cottered cups for slipping in a square tapered spindle, and the bearings and cones of the new axle will likely be perfectly compatible with the cups too. You might just want to check this out before embarking on a quest for some excessively elusive and expensive replacement parts, which you may not even need.

Some good advice in this thread......

The Sugino cups were still being manufactured until recently. Harris had them and I saw them on eBay for as little as $16.95 BIN.

thanks for the help everyone. between the bikeforum and sheldon brown i've gotten so much information. for some reason the bike shops in my area don't seem very keen on getting me on the road w/o charging me $65 and hour to look at my bike. whatever.

This trick might just make it possible to use a Series 3 spindle with original thin adjustable cups. Since the Series 3 spindles are a couple mm narrower between the bearing races, you'd need to be able to take up this slack with the adjustable cups.

Gotta remember to give it a try sometime.

Times have changed. I've been looking for some French BB cups and they aren't cheap anymore. Last new ones I saw on ebay went for $48 + shipping.

https://cgi.ebay.com/French-Bottom-Br...QQcmdZViewItem

Beat up, used cups seem to be fetching about $20 + shipping. Phil cups are still available if you can find a UN72.

Hmmm.....

I just rebuilt a Gitane 600 mixte that has a nice set of Japanese (Tange, I think) French threaded cups. Instead of selling the bike for $100, maybe I should just strip it and part it out.

Sounds like it's time to put mine on Ebay.

My '62 was converted using a #5 spindle and I believe I have a fairly decent stock of them down at the shop... I am gonna have to check the next time I'm in.

I mounted up a Peugeot branded Sakae crank and this dropped an even pound from the bike.

I am going to try to resurrect this thread. I have a '71 U08 frame but I would like to replace the spindle to use a more modern 3 wheel crankset. The original cups are in fine condition after a good cleaning and there is no pitting or damage. What size spindle and what type of crankset could I use?

Your Peugeot's original cups are probably thin walled. If so, they won't work with the 3-series spindles commonly used for 68 mm bottom bracket shells. You'd have to screw the adjustable cup in so far that the lockring wouldn't have enough threads to engage. If you use your original Peugeot cups, you'd probably need a 5-series spindle meant for use with 70 mm Italian bottom brackets ...if you can find one in the right length for the particular crankset you want to use.

Since 3-series spindles are more common (by far), I think the easiest way to do this would be to scrap the Peugeot bottom bracket cups and use cups that aren't thin-walled, like the "Action" branded ones Harris Cyclery is stocking. Then you could choose your crankset and find a common 3-series spindle size to make it work.

Thanks a lot for the advice Skydog. I know that I definitely want the 3 wheeled crankset to handle the hills around here. I will fill you in once I get my hands on something.