What threading is this Bottom Bracket?
 

Can anyone identify the threading from the markings on this BB?
Thanks.

Here ya go...The Climb: French 35xP1 Bottom Brackets

Metric thread. There's no clear picture of the markings on your fixed cup, so I can't distinguish between "French" and "Swiss."

French, if the fixed cup is right-hand thread. Swiss, if the fixed cup is left-hand thread.

It's French threading. Shimano didn't catalogue Swiss fixed cups in 1984. 35 x P1 is the standard Japanese marking for French thread. Japanese manufactured Swiss fixed cups, when you can find them, are typically marked 35 x P1 S1.

Thanks, as always, T-Mar. I have never seen a Japanese manufactured Swiss fixed cup -- I always wondered whether they ever existed.

Strange coincidence - I just yesterday tried to pull the fixed cup on a 1980 Motobecane Grand Touring. It is indeed a Japanese Swiss-threaded BB. I will check the markings tonight. I know it says 35xP1, but I don't remember seeing the S1 marking.

heard a rumor that Sugino made one for Swiss, but never seen it. Never seen or heard of one from Shimano (but the rumor is that Tange made most of the BBs for Shimmy).

Waking this thread up briefly to add some pictures of Tange bottom bracket cups, Swiss threaded. As mentioned earlier by T-Mar, they have the 35xP1 threading marked, a shared size between French and Swiss bottom brackets.

These have the "SI" marking, and sure enough the drive side was Swiss threaded.

Came off a 1976 Motobecane, Nomade Sprint. Motobecanes are my go to choice for French and Swiss sized parts. SR forged french stem, Motobecane french headset, Suntour barcon shifters (not stock on the Nomade Sprint but a pleasant surprise), and a nice V GT Luxe rear derailleur. Meanwhile, their french competitors were using plastic derailleurs and shift levers, death stems, and more.

IME, when it comes to Swiss bottom brackets, while many of the french bike makers did a short splash with them, Motobecane LOVED them. I've found them on Motobecanes from 1976 to 1982.

Note the "SI" marking is much smaller lettering than the rest of the markings.

https://cimg4.ibsrv.net/gimg/bikefor...b36cfc826d.jpg
Both fixed cup and adjustable cup have the "S1" marking, along with 35 x P1.

76 moto
 

My stationary bike setup is a 76 moto super mirage that came with the Tange Swiss thread. My first with this. The s was very small on the markings. Mine was trashed, but luckily my co-op had exactly 1 set.