This seat clamp is used when you do not have seat stay braze-ons and need a location to attach round stays from you rear rack. The clamp replaces your current seat clamp and provides a very secure and easy to reach mounting location. We carry the clamps in two colors, silver and black, and they come in two sizes, 1 1/4″ (31.8mm) 1 3/8″ (34.9mm).
When picking the correct size you will want to measure the outside diameter of your seat tube, not the seat post. To clarify, the seat tube is the tube on your bike frame that the seat post (the part with the saddle attached) slides into.