Originally Posted by
cudak888
For all the hullabaloo over Record cranks cracking at the sharp transition between the spider and the arm (yes, they do crack, and chances are your set is too). I can't recall anyone here ever encountering a failure due to that one specific crack.
The post-CPSC cranks do not smooth the stress riser area; they're as sharp as the post-CPSC versions. There's nothing obvious upon visual inspection to suggest any improvements were made on the later cranks.
-Kurt
The very very late Production cranks where the machined tapered flute was dropped have on the backside reasonably elaborate milling that beefs up the problem area. So, Campagnolo did know, just took a long time to address it and or free up (purchase?) a CNC mill to effect the change.
The very early Record cranks addressed what would become the problem area also, they are machined away, there is a “trench” a slot, that isolates the arm from the spyder.
Way back we had a few broken cranks come through the shop, Toe strap rub always was present at the break about 30 mm above the pedal eye. Campagnolo mad good on those, they DID suggest not setting the toe clips it a way where the strap or shoe would abrade the crank.
interestingly a shop employee had a set of cranks so worn that the wear was to the base of the fluting and on one side beyond. He replaced the crank arms after a customer brought his fractures crank arm in for warranty.