So I am building up a trainer bike with extra parts and the left non-drive side crank (Ultegra 6500) will not stay tight on the Octalink BB. Seems to be but after a few revolutions the crank starts to loosen and wobble. No issues with the drive side. After some research, the consensus SEEMS to be that the internal “grabbers” on the crank arm can get damaged pretty easily? Just wondering if there is any option other than a new crank arm, or any insight that I may not be aware of.
(But if anyone has an Ultegra 6500 left non-drive size crank arm, 175 length, let me know!)
Just in case. There are 2 versions of Octalink v1 and v2 and they are not compatible. v1 has the short splines and v2 the longer ones. Using a v1 crank like the 6500 with a v2 BB will sadly destroy your crank.
I’ve seen some pretty buggered up ones that still work ok. Are you sure you are installing it correctly? Just gotta make sure the splines are in the grooves and don’t force it if they aren’t. Usually if you get early resistance you can back off a hair and move it into the right position.