When I am riding on my trainer, and I am doing 100% ftp there is some clunky/grinding feeling in my drive train (pedaling) at lower cadence below 75 but when I spin above that it smooths out and no grinding type feeling/noise. This does not happen when I ride at lower ftp. Any thoughts, is this normal?
Replace your bottom bracket immediately. Today.
I speak from experience. Good luck.
Took it to the LBS and waiting to hear back thanks!