Inspired by misterright1_99 tensioner from TSC, I fabricated one where the TSC tensioner mounts from the inside of the bracket. As I don't have a vise or a torch, I started with an off the shelf 1 1/2" U-bolt muffler clamp ($2 bucks). The seat tube is 1 1/8" so close enough. I made a bracket with 3 holes in it out of scrap metal. The tensioner mounts on a 3/8" x 2" bolt.