When I replaced the tires last summer, the only Firestone tires I could find in a 315x80R22.5 had a G load rating. The tires on the bus were a L load rating. I went back with the Michelins because they were the only tire I could find with a L load rating and a 75 mph max speed. I talked to five different truck tires shops in Houston. Perhaps they just wanted to sell the Michelins, but I couldn't find a L load range in a 315 on the internet for any other provider either. I did find a couple that were L load rating but had a 55 mph max speed rating.