I assume you’re talking about Mychron brand steering wheels. The Mychron-3 and 4 are completely different shape so the 4 will not mount in the opening of a 3 steering wheel (from the bottom side). You may be able to make an adapter to somehow mount the 4 on top of the wheel or possibly use threaded rod to extend the length of the stud on the bottom of the Mychron.
