Wheels Manufacturing Shim for 1-1/4" Derailleur on 1-1/8" Seat Tube

Wheels Manufacturing Shim for 1-1/4" Derailleur on 1-1/8" Seat Tube. Derailleur shims for adapting front derailleur clamps to a different sized frame seat tube.

Derailleur = the size of the clamp on the front derailleur you have

Frame = the size of the seat tube the derailleur plus shim will fit