Bicycle Mechanics - Old Motobecane bottom bracket

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sternwachter
06-09-04, 07:53 PM
I have a friend who wants to upgrade his old Motobecane Mirage (1975) with cottered cranks to cotterless cranks. He has a crank that he got off of eBay, but doesn't know what sort of threads his bottom bracket has. I presume that they are French threads, but am not sure. Anyone know what size they are?

Thanks.

ComPH
06-10-04, 08:17 AM
There is an excellent reference in the following link: http://www.sheldonbrown.com/velos.html. It shuld explain a lot. Cheers.
dafydd
06-10-04, 03:54 PM
you can probably just switch the axle out if the cups are ok. french cups are 35X1. sugino is the only company i know still making them.

John E
06-10-04, 04:02 PM
Be careful with that fixed cup! Sometime in the mid to late 1970s, Motobecane figured out that fixed cups really should be anticlockwise-threaded. Thus, although early Motos are French-threaded, later ones are Swiss. That 35x1 LH-threaded fixed cup can be very hard to find, although if you get desperate, you can force-thread an English fixed cup, as I did several years ago in my PKN-10, which has served me well ever since.