I noticed the tires looked a little low on my Blazer so I checked the pressure. The tires say the PSI should be at 80. That seems awefully high to me. I've never run more than 35 in any of my car/truck tires. They are LT235/85R16 with an E load rating. Are light truck tires usually higher PSI? Should I fill them to 80 even though my Blazer is probably lighter than a lot of trucks these are designed to be run on?