42T GC Cog for SRAM
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.
- 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 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
- Hub compatibility
- 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.
- Goatlink - improve the long term shifting when using a Shimano rear derailleur (HIGHLY recommended over the longer b-screw)
- 16t replacement cog - smooth out those cassette transitions
- Longer b-screw - necessary with some SRAM GC42 and Shimano GC40 applications. Necessary on all Shimano GC42 applications if not using the Goatlink
- Installation instructions on the GC tech page.
- These are specifically designed for use with SRAM cassettes. The clocking, or rotational orientation, between SRAM and Shimano cassettes is much different so optimal shifting cannot be achieved unless the design is optimized for each separately.
- Design and manufactured in the Minneapolis, MN USA
- Material 7075-T6
- Weight - 86g