Vintage Suntour brakes. These brakes do not require the frame mounted bosses. Instead the M6 bolts pass all the way through an internal sleeve and compress against the flat surface where a threaded boss would normally be. Your frame or fork needs to have the M6 threads to receive the bolt. Or, if you have normal bosses on your fork already, then you can remove the inner sleeve and these should mount like normal, although you may need to get a shorter M6 bolt, depending on how long the bosses on your fork are. These were on a fork, but I see no reason they wouldn't work on the rear as well. Just reverse the pads
