Trying to identify the cups if you can not see the thread direction is a leap of faith when you press buy it online. If you can contribute photos, then maybe it will make it easier to find them. That keeps more Motobécanes on the road, and that makes me happy!

I have just scored lucky with these Shimano Swiss thread cups and 600 arabesque chainset. I was pretty sure from the photos, but the doubt was present! Some cups have “G” for gauche meaning left, these did not. They had “CH” (Switzerland) and “L”, er left? Notice the arms have “CH” on them as well.

CH in this case is a date code. Note the spindle, which is similar but not exactly the same vintage, has CG.
I don't know what the date codes mean (someone here does no doubt), but Shimano had two-letter date codes like this for decades. Maybe still do? I wouldn't know, I only buy vintage parts.

Funny coincidence, isn't it? That a Swiss-thread part would just happen to get the CH date code? Me like.

Mark B

I was wondering why Shimano would feel any need to designate crankarms as "Swiss".

Lol! I thought exactly the same thing. Perhaps it was to point out the bottom bracket was Swiss and not French….a sort of “belt and braces approach”.

So in summery, I have no clue! Lol! Anyone?

Maybe they wanted to write duCHamp but had to go for a break….nice avatar.

I'm 99% certain that I never saw a Swiss-threaded Shimano bottom bracket. Even finding a French threaded one was tough in the '80's and your chances diminished as "French" bicycles were increasingly made in Taiwan.

The way to check is by looking at the fixed cup. If French thread, it'll be right-hand threaded (and prone to working loose). If really Swiss thread, the fixed cup will be left-hand threaded.

According to Sutherland's the "P1" marking indicates French thread.

It is difficult to see in the pictures provided but if I had to bet I'd say that fixed cup is a right hand thread (French). Look near the flange where the threads are ending.

Here is a set of Tange Swiss threaded cups from a 1976-ish Motobecane GJ:

I hope you can see the thread going to the left and the right.

Lol, of course, Duh! August 1978 -CH. What was the chance of that for a Swiss bottom bracket?



Shimano date code found on crankbased wordpress site

Exactly why I started the thread. I had never seen one and had to take a leap of faith on buying as the seller was unsure if it was left hand thread (please let us shorten this now to LHT and RHT! Lol). No SI marking, but a CH and L. Is the CH a date code or indicator of Swiss? Does the L mean left?
As I have a Motobecane soft spot I am always looking out for a “spare” and I think I am not the only one here….A picture data base of the cups would be very helpful when deciding to press the buy it now option….

Fantastic, just what we want photo ID!

Does anyone know, did they quit using the two-letter code after 2003, or is that just when this chart was made?
Speaking of funny coincidences, they recalled a batch of 74 mm BCD granny rings, and the ones that were no good had the date code NG.

Thanks
Mark B

Best I could find was this, they seem to think it repeated itself.
https://forum.bikehub.co.za/topic/14...des-explained/

This is a great link to Shimano’s own site with explanation.
https://www.sjscycles.co.uk/shimano-id-guide/

If you look at the DS cup on that Tange example posted by Schreck83, it has the "S1" marking approx top center indicating Swiss threaded.

Your BB is Shimano. As noted earlier, the CH is definitely a date code (Aug 1978). Shimano was using date codes at that point, and were damn good about putting one on pretty much every item they made (though from what I've seen, typically on only one BB cup in a set). However, unless that indistinct stamp between what appears to be "<52>" and "Shimano" on the DS cup reads S1 your BB doesn't seem to have any S1 marking.

Since you have the BB, there's a very easy test you could perform to eliminate any doubt regarding which type of BB you have. Both French and Swiss BBs use 35mm x 1mm threads. However, a French BB will have RHT on both cups; the Swiss DS cup will be LHT.

If the lockring threads onto both cups, what you have is a French BB. If it won't - and the threads on the DS cup or lockring aren't seriously damaged - it's Swiss.

This is why a thread for identifying Swiss cups is important. I have A Gitane and a Motobécane, so anything with a 35x1 gets my attention for spares. I also look for the “S1” on the cups, which this does not have. It does have however “L” next to the <52>, does this stand for Left? Agreed the CH is a date code, or is it lol!

Yes it is a good tip, trying to thread the lock ring on. My tip is to put your thumb nail in and turn, it tells you where it wants to go, or look right at the first thread, if it goes to the left or right, thats what it is.

I will add a different Swiss cup soon that I have somewhere……..

FWIW: if you have a French- or Swiss-threaded frame, it appears you're not limited to square taper cranksets any more. Hollowtech II, GXP, and 30mm spindle cranksets are apparently now an option.

A firm in Israel is offering French- and Swiss-threaded 24mm Hollowtech II bottom brackets - with a 24-to-22mm adapter included to allow GXP crankset use. They also appear to have a French- or Swiss-threaded 30mm axle BB as well.

https://www.roi-cycles.com/bottom-brackets

No, they're not exactly cheap. But all things considered, they not exactly outrageous either.

Thank you for that important link. I tend tend to build as near as I can period, not concours d'élégance, but I try to keep in the era ball park. However, I have an urge to one day do an upgrade on an old frame. I Think these can look really good. These BB’s are just the job, and could also mean the difference of a rideable bike to a collection of parts.

Nothing in the world is cheap nowadays…..but I think they are priced right for a thread that is obsolete. I am glad someone is making them. Tried looking at shipping and delivery but only displayed “under construction”. The postage and custom charges are what get you….

The firm also lists their products on eBay.

https://www.ebay.com/itm/255077826802

https://www.ebay.com/itm/255797504000

Prices listed on eBay (shipped to US) are a bit higher than on their direct website, but the price includes economy shipping to US. Same seems to be true for the UK (I changed delivery location to the UK and got the same price with "free international shipping" included). No idea what customs charges would add.

I have no commercial interest in the firm and have not done business with them. But as you note, their products might keep a classic bike on the road.

There are also these cups for an IRD (or Tange-Seiki, according to my stash) square tapered cartridge bearing bottom bracket:
https://www.interlocracing.com/shop/...2839#attr=1107

……and there I was thinking I better buy all the Swiss BB that come my way because of world shortage of Swiss threads….lol. Thank you.

Thank you for that, just tried it myself and yes, free shipping! This thread has thrown up some great options for replacing the BB. Thank you.

You're most welcome.

As I said: I have zero commercial interest in the firm, and I've not done business with them. But if I see something that I think might be of general interest to some in the C&V community on eBay/Amazon/wherever, I tend to post the link (with appropriate disclaimers).

Those links looked like something that a subset of the C&V community (those having frames with Swiss BBs) might find useful. Since the firm also makes French-threaded 22/24mm and 30mm BBs, I'd guess if I looked I'd find similar links for their French-threaded BBs on eBay as well. (Edited to add: I checked, and the firm's French threaded 24mm, 22/24mm, and 30mm external bearing BBs are in fact also listed on eBay.)

It's always good to have options.

Swiss 35x1 Stronlight LHD thread

Swiss thread. Stronglight Notice no “SI” or “L” written on the face. I remember reading somewhere that a single circle on a 35x1 cup meant LHD thread? Any views on that?