Originally Posted by
JohnDThompson
What is the bottom bracket, if not original? Can you shift the axle toward the drive side to get more clearance? If the PO installed a threaded bottom bracket, you could put a spacer under the flange of the fixed cup, provided that leaves enough thread engagement for the lockring on the other end of the bottom bracket.
PO reported it was conventional, threaded BB. The spacer is a good idea for a fix.
(Many many Viscount Lambert threads discuss their later BB, their own special design prone to failure and using circlips.)
I confess to frustration at the puzzle, that this couldn't have originally had failed clearance, and yet it does now.
But maybe I should just focus on fix.