This is an optional TKO Flat and Finished Yokomo Differential Ring Set, intended for use with the Yokomo YZ-2 and B-Max series vehicles equipped with a ball differential using the Yokomo B2-506 diff rings (YOKB2-506).
TKO's Flat and Finished Diff Rings use their Totally Flat Technology to produce the Finest Diff Rings available. Using the TKO proprietary process these rings are produced with the faces flat to within 2 microns and are parallel to within 1 micron with a #7 finish (one micron is 40 millionths of an inch - 0.0000040). After processing, the rings are checked with an optical flat and monochromatic light; the ultimate measurement for flatness.
Note: Wipe rings with alcohol or motor spray before installing.
This product was added to our catalog on April 9, 2015
I suppose you could sand or dremel the inside hole a smidge to make it fit better.