This is a new Trek 1.5T. I picked it up Friday, and tried to put some miles on it today. First off the chain rubbed the front derailleur something awful, took it to the shop, they adjusted it. Seemed fine.
Three times (maybe 4?) I would be in the large front sprocket, smallest rear, really getting some speed, and the chain jumped the front sprocket outside. Stopped, got it back on, rode for a while, same thing again. I am not shifting when this happens. Chain seems to be riding on the sprocket fine, no rubbing. The reason I say maybe 4, is it jumped, but before it completely left the sprocket, I back peddled, and got it back on without stopping.
This is scaring my right crank all up. Not nice on a brand new bike. Shop is closed tomorrow, so if I ride, I'll have to stay at least one gear down in the rear. I tried that and it seemed okay.
Any ideas? Just an adjustment problem? I'll let the shop handle it Monday probably, I'm just curious if this is something that happens often. I've been riding my Mtn. bike for a few years, and I never had an issue like this.