When I have my Burley Nomad loaded with groceries my Giant Escape will sometimes shift on it's own. When I took it into the bike shop the derailleur hanger was slightly bent. Am I exceeding the towing ability of my bike? I'd say the trailer, when loaded, weighs somewhere between 50 to 65 pounds. It doesn't do this empty, I towed home a load of groceries this week and there's a grinding noise coming from the drivetrain. Since I'm car free this is the only way I have of going grocery shopping. Just to add the bike weighs ~38lbs and I weigh 317lbs.