French Thread Fixed Cup
 

First ride over 5 miles with my rebuilt '76 Grand Jubilee and the fixed cup unscrewed itself. Originally it was so seized I gave up and repacked the bearings without removing it - and yes I know it's right-hand threads. I suppose there's a chance I freed it up while trying, but it seemed quite stuck.

Sheldon says the only prevention is to make sure it's really tight, and maybe use a thread adhesive.

This is to be my commuter, but it's so comfortable I'd like to try it on a 200k brevet. If my commuter breaks down, walking is no big deal. Depending on the brevet, it might be a big deal.

Questions:

Can this really be tightened down enough to confidently go on a long ride?

If I buy the Velo Orange French thread cartridge BB, would it be any more resistant to unscrewing?

VO also makes an expanding threadless cartridge BB for just a bit more... good option?

i'd do the following.
1. now that it's free, remove both cups and clean the shell and cup real well. some would say to tap and face the shell, but i'm cheap and lazy. use boeshield on the inside to clean and prevent rust.
2. reinstall the fixed cup with adhesive (blue locktight) and tighten it like your life depended on it (which it might at that).
3. pack and adjust the bb.
4. commute.
5. if it works, go on a century or two. it it doesn't, use red locktight. i don't like using red locktight on anything, so i'm a bit averse here.

are you sure it's a '76? i have a '76 moto, and its bb is swiss with the left hand thread on the fixed side.

The first time I road I put together a bike with an Italian BB I tightened the BB as I would normally tighten an English BB. I rode about 200 miles and fixed cup came un-fixed half way through a 40mi ride (it was stop, tighten finger tight, ride 2-3 miles stop tighten finger tight, etc..). When I got home I removed and re-greased the the bottom bracket and tightened the fixed cup, best effort with a 24" breaker bar (no loc-tite). I've got about 1000 miles on the BB and it's stuck solid (that's a good thing!). I don't know why your French BB came loose if you couldn't loosen it before, but as eschlwc said

Yes it can be tightened enough to stay tight. My UO8's right-side cup has be removed a few times, our Peugeot tandem's has been removed. After being tightened properly they've gone a few thousand miles each. Neither has Loctite or other bonding material.

Any threaded BB might loosen up the same way a bearing race, but I suppose there could be styles which don't. The reason they loosen is that the rotating pressure from the spindle makes the race try to roll around the inside of the BB. A cartridge system is subject to the same forces.

I've read good and bad things about the threadless units. Their primary application is a BB with damaged threads.

Be aware that Italian BB's are threaded like French, but with different threads and a larger diameter. In theory they are subject to the same loosening. You don't hear complaints though.

Many French races (Stronglight?) use a 38mm wrench. I've re-assembled out tandem with a high-quality 12" adjustable wrench. Do it carefully so it doesn't slip off, but it can be done.

In addition to what was said above, once you get everything back together, mark both cups with a marker so you can check to make sure everything has stayed tight.

Not certain, no; I should have said 'mid 70's'. I picked up the frame and fork at the local bike co-op, so there are no components to use for dating. The color scheme matches the red/black bike shown here
http://www.flickr.com/photos/2826722...n/photostream/
which is identified by the owner as the '76 catalog.

Reynolds 531, Nervex lugs. Sheldon says Moto was kind of all over the map with BB threading, and I've read they made mid-year changes.

Go to the Trek website to learn how you can more precisely date your GJ from its components. Hubs (if original) are the easiest place to start.

In any case, French fixed cups CAN stay put, if they're properly installed. Check out Sheldon Brown's fixed cup tool. It will help you attain the necessary torque upon installation.

I recall BBM (and others?) recommending teflon plumber's tape on the threads of Italian fixed cups before...

This is an issue I'm a little nervous about. In the last 6 months, I've aquired a French bike and 2 Italian bikes, with no previous "real" experience with either. Lucky for me, I read about this issue, before getting too crazy on upgrade-itis, and I've just left the fixed cups alone, where possible. If they're really stuck in place, that's a good thing, and there's no sense tempting fate, by trying to rework them. :D ;) But I think I'll look into Loc-Tite, for the ones that need it, mostly being the Miele, which had no BB when I got it.

I said earlier that I've had no trouble with two different French fixed cups. I should also add that the Italian fixed cup on the Masi has been no trouble either, though it hasn't yet seen the mileage of those French bikes. If you get them tight enough they do stay put.

One trick is....don't remove them. Unless you have to. ;)

Yep. I kinda think "fixed" implies they don't need any fixing. :D ;) One just needs to figure out which cup is non-fixed, for re-packing, or any other fixing. ;)

Yes. Italian thread has the same issue. If your fixed cup is a Campy clone design you can use the professional fixed cup tool with a cheater bar if your LBS has this:

http://www.os2.dhs.org/~john/fixed-cup-tool.jpg

Otherwise, the Sheldon Brown homemade fixed cup remover tool can also be used to install a fixed cup:

http://sheldonbrown.com/tooltips/images/bbtool-bolt.jpg

Alas, yes.

I've not tried this unit, but my experience with threadless cartridges (i.e. EDCO "Grip") has not been entirely satisfactory. IMHO, if you have usable threads, you may as well use them.

I wonder if you can drill a small hole at the fixed cup flange (if it has enough material sticking out past the BB shell) and safety wire the thing to the chain stay near it so it does not loosen up.......
I just hate the idea of tightening the thing like crazy or using thread locking compound on it...then end up having a big problem later trying to remove it from the frame if you have to replace it.....

Chombi

A better idea would be to drill and tap the BB shell for a set screw to bear against the fixed cup's threads. But if you can get the cup tight enough in the first place, further measures shouldn't be necessary.

Would you really want a set screw possibly buggering up the threads on your fixed cup and then possibly damaging the threads on your BB when you remove it??..........
Anyway, I'd rather just goof around with the easier to replace fixed cup only, if any physical modifications like drilling is done, and not screw around at all with the frameset's BB if it can be avoided.......

Chombi

No. My preferred solution would be to crank the SOB down good and tight. But wiring the cup to the chainstay seems even more primitive than a set screw and less likely to be successful.

"...........and less likely to be successful"????:twitchy:
Dang, they still safety wire all sorts of things even in the most modern of race cars and motorcycles. They continue to use safety wire since anyone can remember on race vehicles cause it works, and works very very well......
I wouldn't doubt if some of the components in rocket motors sent out by the space agencies have safety wiring. I'm sure they must still have it in jet engines too.:rolleyes:
IMO. If safety wiring is done correctly, it does not have to look bad. I betcha I can make it look good If I had a bike with a French threaded BB..... Anyway, not too many people will even see it behind the crank spider......

I use a bit of blue Loctite, tighten it like my life depended on it. Afterwards I always mark the 12 o'clock position on both sides with a small dab of red paint. Don't use a marker as it my be more permanent.
I own 2 Super Mondia's (french Thread) both of them have had this done. After a few hundred miles you can flake off the paint marks if need be.

if you go the blue locktight route, you might want to screw the cup in first with lube on both sets of threads, then remove it, wiping some of the excess lube away with a napkin, then finally add just a few dabs of the blue stuff before locking it down with all your fierce manliness.

a little line of paint on the outside at 12:00 is a great idea.

i kinda like the teflon tape idea too.

^ This.

- And if you're still worried about it, you can always weld the SOB.:innocent:

LOL. :D What about super glue? ;)

If I were doing it, I'd put it on dry threads. I do, in fact. I would think a light coating of oil would sort of negate the effectiveness of the Loctite.

+1

I've never had a fixed cup problem on my UO8 and it's my daily rider. I just grease the threads lightly and tighten the sucker down.

Last night (with some help) I cleaned out the threads, used teflon tape on 1/2 the threads and loctite on the other half, and tightened it down using a breaker bar with the Sheldon Brown tool. I'll put a dab of paint on tonight, although I suspect that any movement will lead to rapid unscrewing.

In the process I've learned that the crankarm extractor to fit my Stronglight cranks is unusual and pricey where available. Fortunately a friend has a Park Tools CCP-1, which fits but is no longer made.

Whoa! It may seem to fit, but that tool is actually designed for TA arms (23.0mm diameter extractor) while Stronglight is 23.35mm diameter extractor. You have a significant risk of stripping the extractor threads if you use the CCP-1 on a Stronglight arm. Sutherland's explicitly warns against this combination:

http://www.os2.dhs.org/~john/park-warning.jpg

After reading far far too much online about the history of crank extractors late last night, I was beginning to suspect this was the case. Nonetheless, it did work.

I'm glad it worked for you this time, but seriously, don't expect it to always work.