I have a late 80s Bianchi frame with Italian-threaded BB, which I assumed was standard. Thought I could replace the fixed cup style with newer Campy Ultra-Torque cups and Veloce crankset, BUT, the cups won't thread into the BB shell - they just spin and don't engage the threads. The cups ordered were for a 68mm BB shell. I have not measured the actual width, but suspect it is 70mm, which I believe is the old standard.

My questions:

1) Is there a difference in (cup) diameter between 68mm and 70mm BB shells that would account for this issue with the cups?

2) Is the 68mm Italian made for newer bikes? I thought 68mm was for English-threaded BBs.

Thanks!

68mm shells are (virtually) always BSC threading = 1.375" diameter. 70mm shells are almost always Italian threading (36mm diameter = 1.42"). So yeah, if you ordered bearings for a 68mm shell they are probably BSC threading and made for 1.375" shell while your shell is 1.42".

The cups are marked 1.375". That would explain it. The LBS ordered the wrong size. Thanks!

The threading is different, too, not just the size. It sounds like your bike is Italian threaded, which means that on both sides of the bike the bb threads are right hand thread. With English thread, the right side of the bike (drive side) is left hand thread, the left side of the bike (non-drive side) is right hand thread.

It is "standard." Italian standard, that is, judging from what's been discussed in the thread.

I think Sheldon said it best: "the problem with standards is that there are so many of them."