Standard French (metric) 35x1mm BB cups are RH thread on both sides. The "Swiss" variant uses LH threaded fixed cups. Some French bikes occasionally used LH threaded cups too.
Motobecane was one of them... The urban myth is that ALL Motobecanes have "Swiss" BBs. I have 2 identical 1974 Motobecane Grand Jubile bikes, one has a standard French BB, the other is Swiss. Of my 10 CR era Motos, only 2 of them have LH threaded fixed cups.
Peugeot also occasionally used Swiss thread BBs AND not all Swiss bikes have LH threaded fixed cups! You can't go by what these bikes were "supposed" to be!
Can you tell what make BB you have? What make Cranks? The cups sometimes have codes or thread sizes stamped into them.
Check the archives, you'll find a lot more info on this.
>http://search.bikelist.org/
Chas. Colerich Oakland, Ca USA
kevin mccaul wrote:
> I have a mid 60s Lejuene track bike that I've been unable to remove fixed
> cup even though it's been soaking in penetrant oil for weeks.
>
> It's been suggested that it is possible that it is a left hand threaded
> French fixed cup like Rene Herse used.
>
> Anyone ever heard of this? I know I haven't.
>
> Thanks,
>
> Kevin McCaul
>
> Silver Spring MD