Shimano Hollowtech-II Crank Spacer

This is a spacer for the spindle on a HollowTech-II MTB bottom bracket that allows narrowing the crank (Q-factor) by 2.5mm - 7.5mm by eliminating one or more of the outboard bearing spacers. This spacer fits over the end of the crank spindle and allows the "fixing bolt" to press against the crank arm, via the spacer, and properly pre-load the bearings.

Above 2.5mm narrower, you'll need to remove some of the inner splines inside the crank arm. I went 0.2" (5mm) deep with a 15/16" drill bit t