How do I check the tire pressure or add air to the inner rear tires of my 2401R MBS? I just bought it new and the 4 outer tires were all close to 20 psi below spec so I am guessing that the other 2 need air also.
You will need to get a truckers air gauge and take the time to learn how to use it. Some people add extensions to their duals to make it easier. When I had an RV, I could check the inners with the extended air gauge. I would add a tire pressure monitoring system if I was you.