Rear Derailleurs

The rear derailleur is a marvel of engineering, simple in operation, but complex in it’s requirements for precision. Invented in 1912, France, by Paul de Vive, a love of “cyclotourisme” created a way to move from a fixed gear hub into an elegant solution of utilizing multiple gears.  Not much has changed in 120 years except for the fine calibration to move the chain incrementally and precisely for each click from your shifters (7 speed sti downtube to 8 speed and above sti shifter levers). Shimano, Campy and SRAM shifters are all designed to work with their rear derailleur counterparts. Mixing a Shimano lever with a SRAM or Campy derailleur wont work. However, brand models all tend to work together. A SRAM Red shifter will work with a SRAM Force rear derailleur, for example.