tensioners flat nylon shoe follows the standard chains 'flat' outer profile. The double roller has 3 ribs that will ride on the tensioners flat shoe. They will more than likely wear 1 or 3 grooves in the nylon shoe and then its the rollers that will be contacting the tensioner. Im sure someone here has run a double roller on a tensioner for thousands of miles and can confim this. I still will run my tensioner on a double roller because I have seem many rollers that were as limp as a noodle coming out. I understand the cogs wear more than the chain so if you get a good set of cogs, it may last alot longer.
