I live in Phoenix, where summer temps are often 110 degrees or more, and the asphalt can reach 130+ degrees. I'm looking to replace the tires on my Toyota Sienna and Camry, and I'm concerned that the standard "T" speed rating isn't really high enough for this area. When you see the number of cars on the side of the road in the summer with blown tires, you start to wonder... I know that under-inflation is the leading cause of tire failure nationwide, but what about in the desert? I've written to three manufacturers and they all insist that their T rated tires are fine for desert use, and that even their high-mileage tires (75K+ miles) are guaranteed to last here. I'm skeptical, but I can't find any test or review data specifically for the desert. Does anyone have any advice or information about buying a U, H, or V rated tire over a T rated one, other than "it couldn't hurt?" Thanks!