Oh dear.
The things you find out when you clean your bike.
I had some wobblyness in my drive-side crank on the last 200 that I first thought was a loose crank and then, when I found the crank to be tight, assumed might be a knackered BB sealed unit.
Stripping everything down reveals that the it is the drive side BB shell that is at fault. When the drive-side of the bearing is screwed in to within 2mm of it's fullest extent, it just turns loose in the BB shell whereas when it was fitted (two years ago) I could tighten it up onto where it butts up against the shell. This leaves the bearing loose in the frame and causes the wobbly drive-side crank.
I tried a brand new BB bearing in there and the same thing happens.
My theory is that the shell itself has been distorted or rusted (although it wasn't too bad to disassemble) and is now too big for the bearing.
I am thinking one way to remedy this would be to bulk it out somehow with a washer or old BB lock ring between the shell and bearing flange which will move the chainset out about 2mm (not a major problem but not ideal) but wondered if anyone had come across this before and had any other suggestions?
H
P.S.This problem has occurred on the same side as the 'Crack of Doom' that turned out to be a crack in the paintwork rather than the frame and with everything stripped down, still seems to be the case.