jjhabbs 

Hi all,

Sheldon Brown says that french threading BBs have right hand threads on both sides. However Sheldon Brown says"


Some French bicycles, notably many Motobécane models, used Swiss thread bottom brackets. These have the same thread and diameter as French, but use a left thread for the fixed cup. This makes life interesting when you need to remove the fixed cup and don't know which way to turn it. Good luck. Phil Wood and velo Orange offer the same options as with French bottom brackets.

Neither cup is moving probably because they are just tight. Can anyone else confirm that my Grand Record has Right hand thread on the adjustable side and a Left hand cup on the drive??

Please let me know.

thanks

JJ

3alarmer 

...I have owned three Grand Record bicycles from the 70's, and a couple of Grand Jubilee's. They were all stock French threading, with no Swissness involved.. You need to pull the adjustable cup and the spindle to get out a fixed cup on a bike that ole anyway, and the adjustable cup is always RH threading, so pull that one using whatever means you deem advisable, then you can see the threading on the other side wwof the shell once you clean it up with a strong light and god eyes or a magnifier.

Pretty good odds it's also RH threading.

crank_addict

John, it may be dependent on what year the GR is and then review the Sutherlands bike bible.

I learned by surprise discovery when servicing my '72 Le Champion - - Swiss threaded Phil unit.

Salamandrine 

It could be either French or Swiss. IIRC the later 70's Motobecanes were more likely to be Swiss, but frankly it's been a long time and I don't really remember. Maybe it was the converse. At any rate they can be either.

So, echoing the above comments, best approach is to remove the adjustable cup, spindle and bearings. Peer inside with a magnifier and a light. It should be possible to discern which way the threads are going.

Also, if you are simply pulling the BB to overhaul it, there's no need to remove the fixed cup. BITD the fixed cups were normally left in place during routine overhauls/repacks -- hence the name fixed cup.

SurferRosa

Depends on the year. I had a '72 with french and a '75 (or '76) with swiss.

crank_addict

I.D. the brand and markings of the cup. Refer 6th Ed. Sutherlands chapter 3, page 3.

jiangshi

What brand BB?

JohnDThompson 

Post a picture of the fixed cup, with the drive side arm removed so it doesn't obscure any markings on the cup.

Failing that, as @crank_addict suggested above,


Source: Sutherland's 6th Edition

bikemig 

As others have said, the markings on the fixed cup are the way to go. Swiss is a bit of a PITA in terms of replacements but the fixed cup is less likely to work itself out. I have a '77 Moto GR I need to overhaul and fix up. I haven't looked at the fixed cup but I'm not pulling it if its in decent shape. Replacement spindles are still available even if finding them takes some tracking down. French production of BBs (stronglight, TA, nervar, etc.) had long production runs and the interchangeability is good.

If you have to replace a Swiss BB, IRD makes conversion cups for their sealed BBs. You can save some dough with French BBs though as cheap cups are available on Amazon.

SurferRosa

Good advice. Unless you're changing the bb or powder coating the frame, leave the fixed cup alone.