Classic & Vintage - cottered french bb spindle replacement

Hi there!
I have an old mercier from the 70s with cottered cranks. I want to change the spindle so it can accept square tapered cranks. I've heard that the walls of a french bb are thin and that different japanese spindles work?? Anyone know if an 80's dura ace 68mm spindle would work? campy 68 ss? campy 70 ss?

Just wondering if any of these will work before I start taking stuff apart?? Thanks!

You need one of these: http://www.billys.co.uk/english/group.php?prod=bbidt8

Or you have to do this: http://www.yellowjersey.org/bbopt.html

Good luck. Let me know how it works out, I'm going to do the same thing on my Peugeot one of these days.

Hi there!
I have an old mercier from the 70s with cottered cranks. I want to change the spindle so it can accept square tapered cranks. I've heard that the walls of a french bb are thin and that different japanese spindles work?? Anyone know if an 80's dura ace 68mm spindle would work? campy 68 ss? campy 70 ss?

Just wondering if any of these will work before I start taking stuff apart?? Thanks!
I've heard that a 70mm spindle will often work because it's just slightly longer. Sheldon Brown's shop has a good selection of BB spindles: http://sheldonbrown.com/harris/bottombrackets.html#axles

An even better choice IMHO is to use the YST threadless bottom brackets, which are just hitting the American market. Only $20 and it'll basically put a standard Shimano-type BB on your frame :) http://sheldonbrown.com/harris/bottombrackets.html#yst

More expensive, but you can get Phil Wood French-thread lockrings ($40ish) and either a Phil Wood BB ($160+) or a Shimano UN72 ($20ish).

More expensive, but you can get Phil Wood French-thread lockrings ($40ish) and either a Phil Wood BB ($160+) or a Shimano UN72 ($20ish).
I've heard that you need to do something special to remove the fixed mounting ring from the Shimano UN72, so that it can be replaced with the Phil mounting rings. How do you do that??

I would simply get the french threaded Sugino BB cups. This will allow use of the more standard "3" series JIS spindles-- much easier. Cups are avaialable via Harris cyclery, probably loose screws as well. Cheapest and best solution, IMHO.

Mox, you just take the cups off the UN72. Both slide off, unlike most other Shimano sealed BBs. Replace the cups with the phil rings.

Mox, you just take the cups off the UN72. Both slide off, unlike most other Shimano sealed BBs. Replace the cups with the phil rings.
Really? I'll have to try this... I've got a UN72 (maybe UN73?) on my road bike and the right-side cup seems to be permanently attached. I'll hafta check on that.

Really? I'll have to try this... I've got a UN72 (maybe UN73?) on my road bike and the right-side cup seems to be permanently attached. I'll hafta check on that.

Was it a week or two weeks ago that I told you exactly the same thing?

Was it a week or two weeks ago that I told you exactly the same thing?
It was about 2 weeks ago :p And I believe you told me some butchering was involved in removing the Shimano mounting ring, which seemed perfectly plausible. Now I hear that the ring just slips right off, which I find astonishing!

Also, have you tried the YST threadless BBs? Seeing as how you like French frames and all...

I tried to go back in and add a smiley to my last post after I read it, but it wasn't an option in edit mode.

When I tried it on an old cartridge bb it required some encouragement with an old screwdriver and hammer. I'm not sure what kind it was, probably Shimano.

The YST BB's look fantastic and the price is right. This is the first I've seen or heard of them. I'll probably never need one because I've got enough spare parts to keep my two French bikes rolling indefinitely.

You need one of these: http://www.billys.co.uk/english/group.php?prod=bbidt8

Or you have to do this: http://www.yellowjersey.org/bbopt.html

Good luck. Let me know how it works out, I'm going to do the same thing on my Peugeot one of these days.

Too funny!! Click a random thread and see my chain cleaning post in your sig. Glad I could help:D ,,,,BD