pstock

When I pulled a rough feeling French BB I saw that the cups and spindle races are all badly scored and pitted.
So, needs replacement. But French thread BB are not that common.

Fortunately, I have quite stash of old but good condition BBs (about 30). And one is French thread but it is Shimano brand.

However, the crankset (entire groupset) on this bike is 8S Campagnolo (probably Chorus) and I want to keep it intact.
I am not a strident purist and so I don't care if this bike sports Shimano BB Cups.

But, I have had problems in the past where the taper on a BB Spindle didn't match the crankset (and the crank arms loosened and rounded out.) and so I believe (is this true) that I should keep the spindle and cranksets matching, Italian.

I have plenty of Italian Spindles.

Question. Should there be any function problems mixing an Italian spindle with Shimano BB Cups? (Like, goodness knows, maybe the races are different radiuses and so they wouldn't play well together?)

JohnDThompson 

With very rare exceptions, the angle of the spindle taper is almost always 2° (the exceptions I'm aware of are some low-end vintage Japanese cranks with 3° tapers, and the old Lambert untapered spindle); the difference is how far the arm you choose inserts onto the spindle:


Source: Sutherland's 4th Edition

As long as the arm seats without bottoming out on the flats or the axle end being flush with the bottom of the extractor hole, it should work without damaging the arm.

That said, I think the issue you're hinting at regarding Italian spindles is that Italian thread bottom brackets are generally 70mm wide, rather than the more standard 68mm wide. Using a spindle designed for a 70mm shell in a 68 mm shell will simply position the arm further from the frame, and may need a spacer under the fixed cup and/or lockring. The chainline will not be exactly the same as if you used a spindle designed for the 68mm shell, but it's unlikely to cause any major problems, and you can always play around with the spacers to adjust the chainline a little.

fietsbob

Yea many little variables ..

Now the cups that thread into the BB shell Shimano makes them in Italian thread as well as British

the Italian BB shell is 2mm wider 70 than the British at 68,
so the Italian spindle may have the cone end of the race , on the axle wider apart ..

then there is cup thickness ,, an example was Campag rifling the edge of a thicker cup to help expel grit,,
as the crank rotates without contacting the BB spindle .. the width between the inner races on the axle that went with that
cup is narrower than the axles the same company made for their other BB assemblies.

another place where measuring the items in question, is a telling procedure.

pstock

Thank you, very helpful.
At the time I suffered chronic wobbly crank syndrome, I thought (or rather I was told) that the problem was a taper different from the "slot" and so I was not getting good contact. My badly drawn diagram shows what I thought was the problem. call it Spindle Gap.

Your explanation makes much better sense.
So, is Spindle Gap or Spindle mis-match (except as you note, in rare exceptions) just a figment of my paranoid imagination?

fietsbob

AFAIK 2 degree is the common taper its the widths on the ends widest and narrowest , that differ..

of course your crankarm may be damaged , no way to tell from here .. riding with it loose is enough to do damage.

pstock

Maybe I wasn't clear.
#1 . This is a French thread BB shell I am trying to refit. the Campy BB that came out of it had a Fixed Cup marked 35x1 and it finally unthreaded French direction.
The spindle from that Campy French BB measures 111mm and is marked 68-ss. I should have lots of 111mm spindles lying around.
Or, if my fears of Spindle gap are nonsense and I am not going to wreck my cranks, then I will just use the Shimano French thread 35x1 BB, either with its original spindle (if it measures 111mm) or another 111mm spindle as identical as I can find?

pstock

My story of a damaged crank was from another bike, way back. This one should still be good.

3alarmer 

...there are also some Ofmega and Avocet branded (made by Ofmega) exceptions,
but it is not so much the taper angle as the size of the spindle ends and sockets, which is smaller.

But as @JohnDThompson has stated for you, the actual taper angle rarely differs enough to matter.

JohnDThompson 

Yes, the Ofmega spindles shared the same 2° taper; they just had a smaller cross-section:


Source: Sutherland's 4th Edition

wrk101

Premise is wrong. Not that common at many LBS that just stock items for modern bikes, but readily available on line at a reasonable cost. Now Swiss threaded BB, those get costly!

3alarmer 

...yes to the above. If you want to go with a sealed unit with French threaded cups, there are various
online guys selling them for about 35 bucks plus tax and shipping for the Velo Orange one.

Velo Orange wants 50 bucks on their site, so how that happens I got no idea.