Tire Air Pressure, 2023 Tundra, 37 inch tires

,A while back I lifted my truck six inches and replaced the factory 32 inch tires with 37 inch Nitto Ridge Grappler tires. The factory 20 inch wheels remain unchanged. Nitto recommends that I run on 29 psi all the way around now, but I build decks for a living and often tow a 12 foot enclosed trailer for tools and a 16 foot landscaping trailer to haul debris. The. 12 foot trailer setup is always around 2,500 lbs, but the 16 foot trailer is often loaded heavily and can reach around 5,000 pounds (trailer and cargo combined on both). My question is "Do I need to increase tire pressure when towing either trailer?" And if so, is there a formula to determine how many more PSI to add? Thanks in advance for any help!

 

Yes. Weight carrying capacity is directly related to tire pressure. It actually takes higher pressure in Your LT tires to carry the same capacity your P or SL rated factory tires could carry. But your LT tires can handle 60-80psi, allowing them to far exceed the capacity of your p rated ones. 29 is very low for LTs, I would suspect to keep the same load capacity as the originals at the original recommended pressure your LTs would be around 36psi or so. But don’t worry, there’s a chart for that!

 

When I went from my stock 265 20's to a 285/65 20 Nitto Recon Grappler I called Nitto & asked them about this. They said run factory pressures for best wear & ride, but you can always increase for when towing & hauling but that's subjective to how much weight you have.