The first year I had my boat and trailer-2002, I had 2 blowouts on my trailer. I put 2 good tires on in exchange and had 2 more blowouts in the next 2 years while keeping 35 psi in them. A buddy of mine ran a front end shop and I asked him to check out the trailer. He did and said that my tires were under-inflated. He said that if I wasnt running 60 psi, I didnt have enough. I inflated to 60 psi and now my tires are 8 years old with ALOT of miles and still arent worn out. I'll never run less than 60 psi on any trailer again. He said this was for any boat trailer or trailer with tires smaller than your vehicle tires.