cottered to cotterless?
 

I have an old Peugeot UO8 with heavy, steel, crappy cottered cranks.

Can I reuse the BB cups and just find a suitable square/splined spindle? Is this a doable modification? Because it's a UO8, I don't want to sink much money into it, but I dislike the cottered cranks.

thanks,

adam

Dunno why not; I did the same thing with my '68 Raleigh Grand Prix. Ditched the Williams cottered crank for an alloy Nervar, and only had to find an appropriate spindle.

So what makes for an appropriate spindle? Is it just a matter of length, or do French BBs use a different bearing size, spindle diameter, anything?

I suppose yo can do it. Just take to the LBS tha french spindle and replace by a squared one with the same diameter and length.

You need to have the right overall length, and also the right distance between the flanges that act as the inner bearing cups. Too little and you'll turn the cups all the way in and it'll still have too much slop. Too much distance, and the cups won't turn in far enough and may interfere with the inner face of the crank arms.

Sheldon Brown covers this , if I am recalling correctly for french threads if you retain the original cups a sugino Italian 70mm axle will allow you to use a cotterless crank. sheldonbrown.com

Square? Yes. Splined? No.

See: http://sheldonbrown.com/velos

Sheldon "Cup And Cone" Brown

I replaced the cottered crank on my UO8 with a square taper spindle. I used the old cups with a Series 5 spindle, however you can get new thick cups and use a more common Series 3 spindle as well.

Ok. This is all starting to make sense.

So if I'm upgrading, how do I determine which spindle length I need?

If I'm reading it right, Sheldon's site lists three 5 series spindles with 32, 38, and 40mm lengths for the right side.

Is it a matter of more space for more rings? 32 = 1 ring / 40 = 3 rings?

Spindle length is dependent on the crank you use. There's a resource on Sheldon's sight (click articles, look for one on crank spindle length).

You can also find old French threaded, Japanese made bottom bracket cups. These have a thicker wall and will work with the more standard "3" series spindles. Sugino, Sake, and Shimano all made these cups; emphaisis on made... you'll have to troll ebuy, but they do show up.

Poguemahone is correct. If you can locate a pair of French-threaded Sugino cups, the rest of the conversion is very easy. Been there ... done that.

Thanks guys,

Ordered some Sugino cups this morning!