I doubt very seriously if any manufacturer would give permission to make a change from what they have already engineered and produced. They simply aren't going to do this for any of us individually. This is the same as an engine manufacturer recommending crankcase oil. They will give you a specification and if you choose to use something else you are on your own. The same with tires/wheels. If you change it, you are the engineering department and the test center.
Good luck whatever you decide to do.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof