45T GC Cog for Shimano 11-speed


Remember when 42t Cassette 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.


  • Optimized for use with Shimano 11 speed 11-40 cassettes
  • Also compatible with Shimano 11 speed 11-42 cassettes
  • 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)

Complementing products:

Tech Specs:

  • Installation instructions on the GC tech page.
  • GC45, 18t replacement cog, and spacer for 18t cog included
  • Design and manufactured in the Minneapolis, MN USA
  • Goatlink 11 is not required but provides improvement in free-chain length (better shifting, less wear), bringing free chain length back to better than with an 11-42 cassette.
  • 11-40:  11-13-15-18-21-24-27-31-35-40-45 -> Weight (XTR) = 410g   Weight (XT) = 490g
  • 11-42:   11-13-15-18-21-24-28-32-37-42-45 -> Weight = 510g
  • Material 7075-T6
  • Weight - 98g
  • Colors - Black, Red, Blue, Silver, Gold