An axle adapter assembly, configured for enabling conversion of an axle installed on a vehicle to fit different center bore sizes of wheel hubs, including: an axle configured for coupling dropouts of fork legs of a lower fork; adapters configured for being inserted within the dropouts; the adapters configured for engaging an outer surface of the axle and retaining the axle upon engagement; and axle pinch shims configured for being inserted into slits of the dropouts and the adapters, wherein upon the insertion, the adapters are aligned with the dropouts, such that shoulders of the adapters retain edges of a wheel hub of the wheel hubs.