MLyon18

Does anyone know a shop that can tap a French threaded bottom bracket? I'm in Albuquerque but will ship the frame for the procedure if it's reasonable.

A while back I came into a 70's French frame, Vitus 888 tubing, which I intended to build up and ride. For a while I've been collecting pieces and parts for the build. I got a Campy 68-SS-120 SS spindle and cups for the BB, French threaded, 35 x 1. The threads in the shell were of course very dry after sitting open for years but I greased and oiled them but would you believe it, when I went to screw the cups in it was like cutting new thread all the way. It's possible that I cross-threaded when I started but I sincerely doubt I did. Both sides of the shell were tough and the left side the worst. I've not yet been able to get the adjustable cup in with a spanner. I'm thinking the shell threads were just real bad, dinged up, and I didn't look until I started in. Or, the Campy SS cups were slightly oversized compared to the shell thread?

At this point I'm doubtful a Stronglight 68x118 BB spindle and cups would make any difference. I'm pretty sure the BB needs tapped else this frame is destined to hang in someones bar or make the metal recyclers. I've looked at the Mavic threadless BB but don't know anyone local who can face and chamfer the shell. And I haven't heard much good about that setup either.

YOur thoughts?

old and new

This issue arrises often here. I can't remember it not arrising a couple-few times per month for several years. Even French bike experts don't nec. agree depending on the situations, severity of the problem and cost that the owner wishes to endure. Phil Wood has pricey options. Others mangage other, less refined ways.
Harris Cyclery's, the late Sheldon Brown gives an account of all this. You can Google search using Google or search threads here which are apt to come-up on Google anyway. All this; in addition to or to prepare for 'till more arrises.

fuzz2050

Velo-Orange makes a $50 french thread bottom bracket.

But that's not an answer to your question. I don't know of many shops that would have the tools on hand to tap a french threaded bottom bracket. Maybe you could have it re-tapped to italian (slightly larger).

V-O is also coming out with another threadless bottom bracket, similar in use to the mavic, but apparently doesn't need the facing/chamfering. Supposed to work well too.

operator

The first thing the OP needs to do is pull the bb out. It'll be obvious if it was corssthreaded with the amount of damaged threads that will spew out of the bb area. If that is the case then just crush it into a cube and sell the scrap metal.

Road Fan

Operator's got it right. Take the parts out, clean the insides again, then with a good light look at the threads and see if they're ok. If they are ok, do some careful measurements of the ID of the threads to verify that French is what you need. Do you have the old BB to compare to the new one?

Bianchigirll 

I have an idea that may help you. I can't recall are both cups threaded the same way? (right hand) if you and you had a spare cup you don't mind ruining you could cut some groves in it to sort of make a chaser to clean the dirt out of the threads.

Grand Bois

I can't remember a cross threaded French bottom bracket shell ever being discussed here.

MLyon18

The bike's has been stripped down and the shell open for some time ..months to years. I don't have the original Stronglight BB. Both cups are right-handed thread and I've basically been running the fixed cup in as far as I can and back out of both sides with plenty of oil. Maybe the threads were rusted or some other way oxidized or were buggered up when I got it. Maybe I crossed them. There's been a small amount of "hair-like" cuttings coming out now and then. There's some buggered up spots I can see now otherwise threads look nice and new - - - now! Still the adjustable side doesn't run smooth enough for me to try and assemble the BB .. if I try and run the adjustable cup in with a spanner I risk sticking it tight and then I be totally screwed. I'm stewing on it. C'est la vie. There's other French frames around .... Thanks all for your thoughts.

I have another BB question concerning an '81 Bianchi mixte I'm working on too. Will post that one later .

BCRider

It doesn't matter how long it's been open. If it wasn't rusty when you screwed in the new BB then the extra force required to work the BB into the shell was going towards messing up the existing threads.

I also believe, without googling to check, that Italian threading is left hand on both sides instead of left-right like English BB threading is. That measn that even TRYING to thread in the left side has messed up the shell threads.

As operator says pull out the BB and check things out but I don't expect much goodness will be found inside if you got it most of the way in before it jammed.

Grand Bois

How does that relate to his French-threaded bottom bracket?

old and new

You've never seen this come up ? I meen problems with French BBs in general.
I believe that I qualified my statement and you went on to further prove it; "agree",
Though you're simply disagreeing, not actually recommending anything meeningfull.
Anything we say suggest can be relavent, even suggested sites.

JohnDThompson 

If this is a steel frame you're unlikely to have completely destroyed the threads by cross-threading. Bianchigirl is right; French thread is 35.0 x 1.0 RH for both the adjustable and fixed sides of the shell. If there's an established shop in your area they may have French thread taps to chase the shell. Otherwise, I have a set but I'm nowhere near Albuquerque.

JohnDThompson 

FWIW, Italian thread is weird, mutant 36.0mm x 24tpi RH on both sides of the shell.

fuzz2050

Might of been my doing. If a BB is really buggered up, it can usually be re-tapped to Italian. Because the diameter is slightly larger, re-taping involves cutting new threads out of the BB shell itself, not the messed up threads. It is, however, expensive, and not something I would recommend Idly.

MLyon18

Well to keep things going -- here's the info requested / discussed. Both the fixed and adjustable cup and stamped with:

"Brev. Inter."
35 x 1
Campagnolo

The spindle is stamed with:

"Brev. Inter."
Campagnolo
68-SS-120
Z

I put my digital calipers on the cup threads and got 34.6 to 34.8 mm on the fixed up, and 34.8 to 35.0 on the adjustable cup. The fixed cup I've been cranking in and out of the shell, mostly on the drive side.

Oversized cups don't seem to be the pro blem. I'm going to check with some LBS - ones that have been around since the '70's but I don't have any expectation of finding BB shell taps let alone French ones.

Any other ideas?

helicomatic

I don't know any shops in your area that would have them, but we have French BB taps. Shoot Norm an email at normans (at) harriscyclery.net if you can't find anyone else to work on it for you.

DMF 

Please allow me to use you as a bad example.

WRONG WRONG WRONG!!! BAD MECHANIC!

NEVER EVER force a threaded fastener in this way. If it's not going in easily, then SOMETHING IS WRONG!

STOP and figure it out. E.g. pull the cup and look for dirt, paint, or cross-threading. Triple-check the match. Ask on bikeforums. etc etc.


.rant off <whew>


For now, pull out the adjustable cup and do what you should have done in the first place.


BTW, how did you arrive at the conclusion that the frame threading is French?

MLyon18

How did I arrive at the conclusion that the frame threading is French? ..... Well, there's the signature of the frame builder, who is French, in large script along the top bar, there are decals in the flag of France colors proudly declaring "Made in France," there are the Vitus 888 tubing stickers on the seat tube and the distinctive Stronglight headset, and the person I got the frame from, who was in possession of the bike at one time (and who with his father had a bike shop specializing in French bikes) told me the frame dated from the 1970's, was French threaded, and what the make of the original Stronglight bottom bracket was and it's Campy equivalent. I can't argue too much with your use of my mechanic technique as a bad example in this instance. Thanks for the lesson, it's good to be reminded of what I already discovered .. let me bang my head into the wall a couple more times. Actually, old bikes often require a bit more muscle than finess, although more often on the disassembly than the build up, I do agree. I started the fixed cup in the shell, the threads engaged, it turned in a bit, met resistance, overcame the resistance, turned easily again, got resistance again, er rah, er rah. Hindsight and arm-chair quarterbacking is always 20/20. I can find other uses for this frame, other than as a rideable bike, should it come to that. Meantime I'm still trying to get some recovery with this thing.

************************************************************

DMF 

Actually, I didn't write it for you, but for the 6 or 7 readers who haven't learned the lesson .. yet. (Or are we all doomed DAMN KITTEN GET OFF THE KEYBOARD to this fate?)


The French are nationalistic - usually to a fault. But they are also perverse. I'm giving odds that your frame wasn't French threaded in the first place.

fuzz2050

It's only been a week, so I don't feel bad resurrecting this thread. To the OP, and all future readers with stripped, bottom brackets, or else just some weird threading (Chatter Lea) the solution is here.
https://www.velo-orange.com/grcruthbobr.html
It fits just about any frame you can throw at it, and doesn't require camfering the bottom bracket shell like the mavic.

operator

What's with the stupid colours.

We don't all ride hipster fix gears.

jccaclimber

You probably cross threaded it. I've never seen a bike with properly cleaned out threads that couldn't have the BB installed at least 1/2 way by hand. Now, this may require a lot of time with a wire brush in the BB shell, some liquid wrench to clean it out, etc. Maybe (but probably not) tapping. However, forcing a fastener, especially such a fine threaded one as a BB (or freewheel) will likely cross thread or strip it. At this point mailing it somewhere with a tap, or retapping it Italian may be your best bet. If you're lucky you might be able to get the BB out, and then put the cup in strait with a lot of finesse. Strength over finesse when disassembling may be ok, but I'll never recommend it putting things back together.

une_vitesse

Wow, you have a set of french bb thread taps? VAR, or park? If the latter, what's the item #??? I run a shop in california and believe it or not, we see a fair amount of french bikes coming in needing bb work.

Tom Velo Orange

Re stupid colours....Chalk that up to a mis-communication with the factory. Some oven cleaner can fix that rather quickly. Think of it as a limited edition- we didn't even charge you extra for it!
heh.

If you are sure the frames is french thread and the threads aren't completely boogered up, we do have french thread BB sets as well:
https://velo-orange.com/grcrufrthbob.html
The French thread BB's are about $10 less.
Harris cyclery regularly stocks them, as well as a number of shops across the states, Canada, and, of all places, FRANCE.
The irony is not lost on us....

DMF 

Hey, that's a pretty interesting site. Thanks for the link.