The GC 49 cassette extender cog allow you to modify your 11 speed Shimano 11-42T cassette to create an ultra-wide range 11T-49T cassette. Includes 18T cassette cog for optimal gearing in the smaller cogs as well as WolfCage adaptor and derailleur pulley. GC49 features 7 shift gates for faster shifting.
Compatible with Shimano 11-40 and 11-42 11-speed cassettes
Shimano rear derailleurs require the use of the WolfCage with a GC49