Originally Posted by
Alias530
I thought it might be rubbing but it does it on a 25mm road tire too and the frame had clearance for 50+mm tires
sounds like its metal crunching/grinding
there's some rubbing from those rubber spike things on new tires on the inside of the front fork
I wasn't thinking of rubbing within the bike, but against the yoke that supports the trainer's roller. The axle supports aren't super rigid, so when working hard the bike can rock, moving the tire along the roller. Flex hard enough and the tire moves beyond the end of the roller and rubs the supporting yoke.