I have been racing for 60+ years. Towed everything from open trailer to 3 axel stackers and was probably over loaded 1/2 the time. Tire pressure is important, check it often and make sure all tires are the same. BUT, one year I bought a new 28ft enclosed and even with all the precautions I blew 9 tires in one summer. Never could find a reason for the failures. Sold it and got my first 3 axel. I currently have a 32ft enclosed 3 axel that has never had a failure. Tires, on these with 15in wheels I use Goodyear Wranglers from Wal Mart. When one wears down I get 6 new ones. With this current 3 axel and my 20ft Featherlite open I run 40lbs of air. No formula it just seems to work....check it often.