The Truing Stand Bearing Mount bolts to the V-notch at the top of a standard
wheel truing stand (e.g. Park Tool Professional TS-2.2). It enables the hub to seat
directly into the top of the stand, for easier wheel building. Although ideal
for 42 mm outer diameter (OD) bearings, unicycles with 40 mm OD bearings can
also be built using these mounts.