As the question says is there a difference? We have 22" wheels on our explorer and have been using the car a bit more off road going camping as we need 2 cars with the camper and bike trailer. Car still runs highway tyres. Want to get som a/t or m/t to fit. Do they make them that big only want 31" maybe I say maybe 33". Problem is will my current rims be up to going off road. Not hardcore just fire trail type stuff. Want off road tyres for hopefully a bit more sidewall between the rim and ground and a bit more puncture resistant plus better grip.