I'm running 35X 12.50's on stock 18" wheels using Trail Grappler M/T's. What PSI should I run them when not towing as well as when I do decide to tow? Most I would tow is a car (Gt500) and trailer.
See if you can find some load charts for the tires. I know toyo will give you a recommended psi for a certain load. So then you can run your front and rear axle over the scales and then you can lower your psi to match up with the loading. Then fill your tires back up prior to towing.
Mark across the tread with a paint or grease pin.
Drive straight for about a block.
If it wears in the middle too much air, on the edges not enough.
You want the line to disappear evenly.