Why We Make This We don’t, because the good people at Park already made the perfect tool for the job. Why You Want It In order to use our large and efficient bearings with the smaller Micro Spline lock ring, we use a threaded insert. During service, you might want to remove it. When deciding which tool interface to use, we chose the Park Tool FR-1.3 because it has a deep enough socket to clear the thru axle and a narrow enough spline pattern to fit within the Shimano lock ring threads. 12 splines, 22.6mm diameter fits Shimano®, Sachs® Aris, Sun Race®, DNP® Epoch and other 5–10 speed freewheels. The FR-1.3 includes an enlarged thru hole to accommodate 14mm axles. The base of the tool can be installed in a vise or used with a 1" socket or wrench.