Hi,
According to the Michelin tire inflation and weight guide, when Passenger tires are installed on a truck, then the weight rating should be de-rated by about 10% (or was it 15%?). So a 'P' tire rated at 2,000 pounds is really only good for 1800 or 1700 pounds while mounted on a truck.
LT truck tires do not suffer from derating. However they are also only rated at about 75 MPH, and if above that speed, then LT tires must be derated by 10% weight factor as well.
Most 'P' tires are rated at 87 MPH, while some are rated as high as 135 MPH, and specialty tires rated at 185+ MPH. But that speed rating is only during the first 5 years after manufacture, then who knows what will happen to a tire at 150+ MPH?
Personally I would change to the stiffer sidewall LT tires. Have you ever noticed that the front of the trailer can push the back of the truck a bit sideways while going down a hill? LT tires are stiff enough to prevent this.
Fred.
