BB won't spin when installed
 

This is a weird one: my co-op sold a Campy Record cartridge bottom bracket on eBay. It appeared to be barely used, and the spindle spun freely in hand.

But the buyer claims that when he installs the BB in the frame and tightens it, the spindle will no longer spin. He says the problem begins with only 10nm of torque (51nm is recommended torque).

Any idea what's going on here? I assume the BB is shot, but the buyer wanted to see if there were any quick fixes that might solve the issue.

The bearings are probably bound up from misalignment. Tell the buyer to try this: tighten the adjustable cup just snug, then tap the ends of the spindle with a hammer, not too hard, not too soft. This will align the spindle and bearings and the cups with each other, and should allow full installation torque.

Thanks. I've passed on the word to the buyer--I'll update with how it goes.

Are the BB cups properly faced?

What are the odds these two threads might be related, and that the guy who started the other thread might be the customer?

https://www.bikeforums.net/bicycle-m...-10-speed.html

I had a similar issue with a Tioga BB recently, which is why I responded about facing to both threads.

Ya, I wouldn't go hitting with a hammer... face the darn thing.

BTW the technique I described above applies to cartridge bearing hubs as well as BBs. Radial-contact cartridge bearings don't self-align the way angular-contact cup-and-cone bearings do. You have to "persuade" them to line up with a bit of a love tap. If you don't do this, they will eat themselves within a few hundred miles or so.

I'm really hoping this is true! If not, I hope the other thread starter is reading this one too.

I'm not saying pound on it with a 3# sledge. It's just a love tap.

What would facing do for this problem? The flange on these is aluminum, and would yield easily to the force put on in by threading in to its torque number. And the NDS cup has no flange, so facing won't do anything for that side.

I mean, it won't hurt anything to face the DS of the shell, but I don't see it fixing this either. Good luck finding a shop with either the tools or the experience to face properly anyway.

I don't think an aluminum shell is going to "yield" without pushing in on the bearing in the process. That flimsy carbon spacer isn't going to keep the bearing aligned if the cup isn't.

There is a lot of clearance between BB shells and cups, and that clearance can let the cup rock small amounts unless it is allowed to tighten against the threads symmetrically. If the lip is parked against uneven BB shell face, the cup will cant.

Sure, it will a little bit. But the flange is quite a ways outboard of those bearings, I'm guessing about 15mm. There's a lot of soft aluminum between the flange and the bearing.
Not much at all, that's pretty much a cosmetic piece. But everything will align to the axle, which is the stiffest part of the assembly. That is why you should give it a good love tap, that will set things where they need to be to work.

HA! Yes, that's him! Too funny.

I had that problem on my Supercorsa frame and chasing the threads fixed it.