tronnyjenkins 

Chombi1 

Yup, both left hand threaded at the fixed cup for Swiss and British. Difference is the thread pitch. Forcing it in will most likely damage the threads on the BB shell.....not good....

Aubergine 

verktyg 

+1

Post some pictures when you can or a link to the CL sale or eBay auction.

From about 1984 on, most French bikes had British/ISO threads, even with metric diameter tubes. Eventually French, Swiss and Italian threaded BBs became obsolete - so did British threads which were replaced with the almost identical ISO standard threads.

Please note to ALL guessers, in 40 years I can count on 3 hands the number of non Swiss made bikes with Swiss threaded BBs! In the 70's I saw French bikes with British threaded cups forced in and other hammersmith screwups.

History is written by those who weren't there!

verktyg

mgopack42 

Hey, my 2011 or 2012 Pinarello has Italian BB, so not totally obsolete!
So does my wife's 2003 Fondriest. My 80's Ciocc too! I guess I am a Italophile (is that a word?)

verktyg 

I didn't check my facts and I figured someone was going to jump in on that comment. Eventually is a long time....

My 1988 Bianchi Giro and 1990 Bianchi Mondiale both have Italian BBs so does my Billato built 1990's Giordana Capella.

The Italians are still using 36mm x 24 TPI - metric diameter with inch thread pitch... WRONG can go on for a long time!

If the French did this rather than the sacred Italians, people would be completely hysterical! OMG the world is ending!

verktyg

tronnyjenkins 

Chombi1 

Looks like a high quality frameset. The paint scheme and color is a bit of an acquired taste, but I guess, typical for when the bike was built. So who or what does "Lecoulant" mean??

wrk101

"Please note to ALL guessers, in 40 years I can count on 3 hands the number of non Swiss made bikes with Swiss threaded BBs! In the 70's I saw French bikes with British threaded cups forced in and other hammersmith screwups."

My experience differs.

I have found a lot of Swiss bottom brackets on French bikes, particularly on Motobecanes. They seem to have loved Swiss BB. I've seen them on anything from about 1977 to 1984 Motobecanes. I've seen so many on Motobecanes, anymore, I seek out Motobecane beater bikes just to harvest Swiss BB.

Now I have never seen them on a French bike newer than 1984.

MarcoBianchi

Lecoulant was a French cycling team in the 70' they raced with Mercier and Gitane, I was unaware that the made bikes.

verktyg 

Not questioning your experiences.

Knee jerk reaction to so many posts that bring up Swiss BBs on French bikes.

This was my first chance to rant about French bikes with supposed Swiss cups. Perhaps I should continue to suggest that folks measure first. The big concern is that if someone can't get a fixed cup out of a French bike, the immediate assumption is that it must have Swiss threads. Turning a stuck French fixed cup clockwise as if it was LH thread makes matters worse!

Until I got back into collecting bikes again in 2006 I had very little experience with Motobecanes. I currently own or have owned a total of 14 Motos from a 1972 Le Champion to a 1984 Grand Record including a Riviera folder and mid 70's French market Nobly. They all have French BBs.

N=14 is not an impressive sampling but I currently have 40+ French bikes in my collection and only one has a Swiss BB - my 1983 Peugeot PSV-10.

As far as French oddities go, in the late 70's we started seeing some Peugeot U-08s coming into our shop for service that had British threaded BBs, pedals and FWs on otherwise metric bikes. They were probably made in Canada.

I have a 1974 Gitane Tour de France that came from Australia. I got it as a frame with a Campy SR headset and BB. I was surprised it had British BB cups and figured someone had munged them up. I checked the headset and it was British too. The steerer had 1"-24 threads and was 1" in diameter vs 25mm. The rest of the tubes were metric. The BB had perfect Brit threads! Gitane didn't make the move to British threads until the early 80's it was probably made for the OZ, NZ, UK market.

I've never seen a Gitane or Bertin for that matter with a Swiss BB. We sold both of those brands so N=xxxx.

verktyg

Kovkov

That's strange. According to dimensions and Sheldon Brown's cribsheet British cups should thread fully into a 35X1mm threaded shell but would be slightly loose. The other way around it would bind.

tronnyjenkins 

verktyg 

@tronnyjenkins too...

NON! Misinterpretation of the writings of St. Sheldon or gasp, he's wrong! That's hammersmithing! The diameter will fit a little loose but the thread pitch is all wrong!

The celeste area shows the pitch error or misifit over 4 threads or turns. At that point you run into a definite interference between the cup threads and BB threads.

BRITISH Right Hand Thread Adjustable Cup Left Hand Thread Fixed Cup 1.370” x 24 TPI (34.8 x 1.06 mm) The ISO Standard is 1.375" x 24 TPI .005" larger (34.9 x 1.06 mm)

FRENCH Right Hand Thread Adjustable Cup Right Hand Thread Fixed Cup 35 mm X 1mm (1.378” x 25.4 TPI)

In reality, these dimensions are nominal because a perfectly cut BB thread is going to have a slightly larger major diameter and cups will have a slightly smaller outside diameter for clearance. This is called the thread tolerance.

More reality, BB threads are rarely accurate diameter wise and cups are usually undersize. Call it "manufacturing tolerance"... BBs that have been "chased with a tap to clean up the threads can frequently be oversize. Paint, dirt, rust and other crud in the BB threads can make removing and reinstalling cups hard.

If cups screw in too easily by hand, get some Loctite Blue Thread Locker.

And yes, a British adjustable cup can be turned 2-5 threads into a French threaded BB shell before the pitch misfit causes the threads to start to seize. A left hand British fixed cup can slightly start into right hand French BB but will go no further than maybe 1/2 turn without hamfisted force!

Back in the 70's when I was working on bikes for a living, we worked on lots of French bikes and quite a few had British replacement cups forced in by hammer mechanics. And yes they were Brit cups, not Swiss. When one is forced into a French BB, at about 6 -7 turns the cup which is harder starts to mush over all the BB threads. It becomes an interference force fit.

Hope this clears up the mud a little.

verktyg

Dan Burkhart 

Far as I know current production Pinarello bikes have Italian threaded bottom brackets. They followed the rest of the industry going over the press fit cliff, but managed to catch a branch on the way down, and switched back.

verktyg 

Why are French and Italian BB threads RH on both sides? Never heard an answer to that or even the question but here goes...

By using RH threads on both side of the BB a single long tap can cut the threads in both sides in one operation. It also eliminates any alignment issues that could result from tapping both sides of the BB shell.

Most BB shells came pre-threaded with a partial thread which was enough to get the BB taps started after the frame was brazed.

Something to consider, much of the manufacturing facilities and equipment in continental Europe was severely damaged during WW II. Bicycle production was one of the first transportation industries to start up after the end of the war. In some places, equipment used to machining bicycle parts and components predated WW I and wasn't updated until at least the late 1970's.

Between outdated equipment, business and labor practices, these combined with the unexpected demand for bicycles during the boom, creating a condition of chronic shortages in the French bicycle component industry. This eventually opened the door to Japanese competitors who out did the French manufacturers.

So, like many things in the cycling world, not much changed during the 100 year period between the late 1800's and late 1900's. "That's the way we've always done it!"

That's why the sky is blue....

verktyg

jimmuller 

Uh, let me guess! To get to the other side? Because they can? Three BB's walked into a bar...?

The French got it wrong but the Italians must have had a very good reason.

Choke 

Pretty much every Italian builder who still uses threaded BBs still does them in Italian threads.....Bianchi is the only one I know for sure that switched (sometime in the 90s). Also, Eddy Merckx bikes all have an Italian BB.

And Italophile is definitely a word....if you look at the list of bikes under my name only two of those don't have an Italian threaded BB.

79pmooney

I am one who hopes Italian BBs never go away. I also hope to never have the occasion to to use one. (Huh?)

Italian BBs have a large enough diameter that all the other standards can be re-tapped to Italian after the threads get massacred. There's that truly sweet C&V frame out there you have always wanted but the English/French/Swiss BB threads are trashed. Grab it and have the BB re-tapped. Yes, the curse of the RH thread fixed cup, but except for that, the frame is good as new.

(And an aside - the perfect tool for tightening RH fixed cups - the frame. Put the fixed cup flange in a bench vise with good clean and smooth jaws. N0ow you can use both hands, one on the rear triangle, the other on down tube and exert rear force. You will have to do the same operation to unscrew the cup, but it won't unscrew on the road. When I did this, I hung the frame with a string down from the ceiling over the vice with forks out to the dropout, head tube and seat lug.)

Ben

tronnyjenkins 

Well, when I'm wrong I'm dead wrong.
This bike has a French threaded BB. How the other day I threaded the fixed cup in by hand at all is a mystery. Upon second inspection and not taking stupid pills today, I discovered some (as Sheldon likes to call it) right (wrong!) threading.


I guess this is both good and bad news? Haha. I'll go hide now and avoid the switch on my backside.

fietsbob

Bianchi USA began using Pac Rim companies to make their bikes , they sell here, then..
the Italian ones stopped being imported , at any modest price points, from Europe.





.....

Choke 

That may well have been the impetus but my 1996 Italian built (Reparto Corse) frame has an English BB. Needless to say it surprised me when an Italian BB wouldn't fit.

jimmuller 

My '87 Bianchi Brava has an English BB too. It would have been one made in the Pac Rim, probably Japan but perhaps not.

John E

I heard that the Brits. patented the LH-threaded fixed cup and the Italians and French didn't want to pay royalties.

The one benefit of RH thread on both sides is that one can use adjustable cups on both sides for a slightly adjustable chainline. Otherwise, I do hate inherently self-loosening RH-threaded Italian and French fixed cups, which almost always seem to require LocTite.

I have successfully force-threaded an aluminum 1.375x24 fixed cup into the Swiss-threaded BB shell of a 1980 Peugeot PKN-10. Works like a champ and facilitated my switch from a Stronglight double to a Sugino triple.

agnewton

I have a UO-10 with a BB that I discovered was Swiss this summer. An English threaded variable cup could be threaded in all the way by hand, but had a bit of play in the threads that could be "removed" by snugging up the lock ring a bit (probably not the best thing for the threads). On the other side, an English threaded fixed cup could only be turned by hand a half revolution or so before binding. The proper French/ Swiss threaded variable/ fixed cups could be threaded in by hand without any play or resistance in the threads (as engineered). Not sure if the difference between the two sides would be different engineering tolerances or an artifact of some historic hammersmithing, but the variable cup concurred with Sheldon and the fixed cup demonstrated the thread interference described by verktyg. Italian cups were incompatible.