18T Sprocket + Spacer [ 1x11 ]

Improve the backpedal performance of your 11 speed Shimano cassette without losing range.

Note: All OneUp Components 50T and 45T expander sprockets kits already include our 18T sprocket. 

The OneUp 18T sprocket and spacer kit replaces the 17T and 19T sprockets within a stock 11 speed Shimano cassette and spaces the cassette out by 4mm which greatly reduces back-pedal chain dropping issues. The 18T kit removes one gear from your cassette without changing the stock range and is only compatible with 11-speed components.  Simply use your low limit to remove one click from your rear shifter.


Sprocket material:   Chrome plated hardened steel

Sprocket weight: 24g (18T),

Compatibility: For XT/XTR M8000/M9000 11-40T, XT M8000 11-42 cassettes.  Also compatible with the OneUp 10T cluster.

Cassette progression:  

11-40, 11-13-15-18-21-24-27-31-35-40 

11-42, 11-13-15-18-21-24-28-32-37-42



  • Mount the OneUp green spacer first and reinstall all sprockets except the stock 17T and 19T sprockets (these are replaced with our 18T and aluminum spacer).
  • Adjust the low limit screw to eliminate the final click on your shifter