Why don they work with Shimano and Campy Compact cranks?
The inner compact Q-Ring will fit on Campy and Shimano compact cranks, however the spyder on these two compact cranksets does not allow a proper fit for the Q-Ring. No solution is available without excessive machining. You can order and use the inner 36T Q-Ring combined with your current standard round outer 50T chainring. You can use Q-Rings on the 110/130BCD SRM Dura-Ace Compact cranks. Just order the 36T 110BCD inner and 50T 130BCD outer Q-Rings.
