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Remember when 42t cassette extender cogs were considered big? The 1x evolution continues now with the even bigger GC45 for 11-speed Shimano mountain bike cassettes. With the GC 45 on your Shimano cassette you will have an overall range that is very similar to the 10-42 from SRAM but given the same front chainring, you get an easier climbing gear. An 18t cog and spacer are included with the GC45 to eliminate the large tooth gap in the smaller cogs.

  • GC45, 18t replacement cog, and spacer for 18t cog included


  • Optimized for use with Shimano 11-speed 11-40 cassettes
  • Also compatible with Shimano 11-speed 11-42 cassettes
  • length of threaded section on the lock ring should be greater than 4 mm 
  • Can be run in 2x configuration with a long cage (SGS) rear derailleur (max front difference is 13t with a double and 11-45 cassette)



Related Products

Goatlink 11 - Highly recommended, this reduces the free chain length with the GC45 to better than the 11-42 in the stock configuration.  This means it will shift more crisply than the stock 11-42.

Wolf Tooth’s patent-pending Drop-Stop® wide/narrow chainrings


    Tech Specs

    Weight: 98g
    Material: 7075-T6 aluminum
    Included: GC45, 18t replacement cog, and spacer for 18t cog included
    Made in the USA

      WARNING Handling this product will expose you to chemicals, including lead, known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling. For further information go to​

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