Campagnolo Press fit BB, play in crank, but not any more..

neeb
neeb Posts: 4,470
edited November 2013 in Workshop
OK, this is a bit of a weird one, and as it is apparently no longer a problem, perhaps I should just ignore it. But I'm curious...

I've just built up a new frame with press fit Campagnolo Ultra Torque cups, 86.5 x 41. The cups had previously been installed in an identical frame, which had to go back due to a problem after about 100 miles. On installing the cups and cranks (Super Record, Ti spindle) on the second frame, there was a little bit of play in the cranks even after tightening the fixing bolt to full specified torque. The wavy washer and spring clip were installed correctly. The actual BB shell width measured with a micrometer was about 86.1 - 86.3, a little under spec but not excessively (I understand +/- 0.5mm in BB86 is acceptable). Anyway, I worried about this, reinstalled both the cups and the cranks, inspected everything.

Then today I just thought b*gger it and went for a 30 mile ride - pedalling felt fine, and when I got back the play had gone!

I'm guessing maybe the cups had somehow become slightly out-of-shape and riding knocked them back into round, or something like that?