Cassettes/Freewheels

The product that set the standard and still the best available! The GC line of cassette extender cogs allow you to modify your 10-speed cassette into a wide range cassette. To achieve the optimal shifting, the GCs are optimized for Shimano or SRAM cassette so always select the correct type for the cassette brand you have. Compatibility: - Compatible with SRAM 10-speed cassettes listed on the GC tech page - Compatible with all 10-speed chains - Note that you may need a longer chain that you currently have on your bike - Chain stretch should be less than .5 when installing a new GC - Compatible with all 10 speed rear derailleurs except non-clutch type SRAM rear derailleurs model year 2012 and older - These older rear derailleurs do work with the GC40. - Can be run in 2x configuration with a long cage rear derailleur - These may fit tightly on some over-sized hub bodies such as Stan's No Tubes 3.30 and the Easton X4 hubs. With a little filing and some grease they will go on.

The product that set the standard and still the best available! The GC line of cassette extender cogs allow you to modify your 10 speed cassette into a wide range cassette. To achieve the optimal shifting, the GCs are optimized for Shimano or SRAM cassette -- always select the correct type for the brand of cassette you have. Compatibility: - Compatible with Shimano 10 speed cassettes listed on the GC tech page - Compatible with all 10 speed chains - Note that you may need a longer chain that you currently have on your bike - Chain stretch should be less than .5 when installing a new GC - Compatible with all 10 speed rear derailleurs except non-clutch type SRAM rear derailleurs model year 2012 and older - Can be run in 2x configuration with a long cage rear derailleur