honesthans

Hi Everyone,
I'm trying to fit a Stronglight 99 triple crankset to an old Schwinn Super Sport & I need to find the right bottom bracket for it. From what I've been able to figure out a 99 typically took a 124mm ISO square taper spindle for a triple. Is there anything readily available that's close to the that? I haven't had much luck finding anything & most available square taper BBs are JIS taper or unspecified. I was hoping to spend about ~$30 and get this job done relatively quickly, so I can't afford any boutique parts or to watch ebay for a long time for reasonably priced parts to show up. If I were to go with a JIS spindle bottom bracket, what would be the JIS equivalent size, assuming I need 124mm for an ISO spindle? Thanks

Andrew R Stewart 

have you test fitted your cranks to a specific BB spindle yet? There's some similarity and some differences in the 1970s cranks in their taper angles and the width across the flats which determine actual fit and ring proximity to the frame. Back then the "standards" were not really agreed on. The era of export trade being the profit driver hadn't yet come about so crank/axle tapers were more nationally based then internationally accepted.

If I were the OP I would frequent a LBS that does a lot of service work and ask to play with their Shimano UN-55 BBs as a start. (If for no other reason in that most other brands follow the lead that the 500 lb gorilla that Shimano is). Andy

63rickert

https://www.ebay.fr/itm/JEU-DE-PEDAL...4AAOSw7FRc6V7y

First on list at ebay.fr. Unfortunate price on shipping. Main point should be there is no scarcity of old Stronglight parts. Only a minute portion of parts available are going to be listed because this old stuff sells real slow. Ask any of larger French sellers or even any vintage seller here in States and you have a good chance of getting a positive answer.

Don't spend money until you have a real good idea what will fit. Put a 118 or 120 or 122 spindle in there and measure how far off chainline is.

I gave away my last UN-55, can confirm they work just fine with Stronglight crankarms. Have used them as placekeepers on a few old bikes. Only reason not to use a UN-55 is cosmetics, on an old bike a pair of cups looks nicer than a cartridge. If you care about such things.

No one is ever going to quiet all the cavils and quibbles about JIS versus ISO. In practice it does not make any difference, ever. If the crank goes on and tightens solid you are good to go. Once in a great while there is some kind of an issue and the crank arm bottoms out or won't get tight. Those problems are always something other than JIS/ISO. And really very infrequent.

rosefarts

I recently fitted a Campy crank on a JIS BB. It’s fine. It’ll stick out 4.5mm further so get a little shorter spindle. Putting a JIS crank on an ISO bb is a bigger issue since it can bottom out.

It doesn’t come out as easily with a crank puller for maintenance but it’s fine.

JohnDThompson 

I used a Stronglight 125 spindle with my mod. 99 triple crank. From the Stronglight catalog:

dedhed

First you need the adaptor.

https://www.ebay.com/itm/Euro-to-Ame...kAAOSwzJ5XbDPj