Is there a hypernym for wheels and tracks (possibly also, though rarer, mechanical legs and hovecraft skirts), that is the interface or system that supports a vehicle on land and that (except for hovercraft skirts, I guess) provides traction/grip?
I found running gear and driving gear, so that gear might serve as a hypernym, but it sounds overly generic and can be confused with gear (train), for gear shifting, which might be only a (optional) companion of the system I'm looking to name.
I also found motion system, which may be applicable only in specific domains other than locomotion and may extend to powering (engine).
Perhaps mechanical locomotion system, which might however exclude hovercraft skirts, as well as include propulsion?