i have a late 70s motobecane frame. It has a french BB. Ive removed the fixed cup and go to thread in my new cups...and they wont go.

I can thread the fixed cup and the adjustable cup in the non drive side no problem. The fixed cup that i took out goes right back in with the counter clockwise thread like it is suppose to on the drive side but i cant get it started on the adjustable side. were the threads per inch or pitch different on the non drive side fixed cups? I have never seen this before and ive done a peugeot with great success.

if i hold up the new cups over the threads of the old cups...they appear to match up thread wise just fine. I dont get it.

The new cups i have are 35xp1 french threaded.

ANyone?

UPdate: I found this.....

All cups on the non-gear/left side un-thread in the direction the crankarms move while pedaling

French fixed cups (gear side) un-thread in the direction the crankarms move when pedaling backwards.

Swiss fixed cups un-thread in the direction the crankarm moves while pedaling forwards.

British fixed cups un-thread in the direction the crankarm moves while pedaling forwards.

Ill bet it is Swiss...
when i thread in the original fixed cup i have to thread it in going in a counter clockwise rotation (same direction as the cranks going forward. It THreads right it.....

SO....looks like i have a french bb for the parts bin.

Funny...the damn bike says MADE IN FRANCE right on it in big bold letters so i figured it was the same as my peugeot....