Originally Posted by
pipeliner
We have been ruining the bearings in the BBs. Over the course of less than 1000 miles we have ruined 3 of them and the current one is noisy. They start popping and cracking and I replace them.
I didn’t know there were incompatible Octalink systems. I will look into that and make sure that isn’t why we have stripped out the cranks.
Common causes of trashing bottom bracket bearings include a bottom bracket shell that is not radially aligned side to side and/or a timing chain that is way too taught possibly coupled with one or both of the chainrings being non-concentric about the bottom bracket spindle
The former is typically implicated for separate bearing cups such as in Hollowtech where the bearings may not be aligned due to poor bottom bracket frame machining. I would believe that an Octalink cartridge would not have this issue.
The latter may be something to look at. If the timing chain is very taught and/or changes "taughtness" through the 360 degree rotation of the crank, I would give some focus there. Changing radial load on a bearing through each rotation can significantly reduce the operational life of the bearing. This may be the cause of your shortened bearing life.