D-Load Ratings Vs. C-Load Ratings for Tire Ride Comfortby Tim Plaehn
Light truck tires, those designated with a LT in front of the tire size, use a letter rating to designate the load capacity of the tire. The most common light truck tire load ranges are C, D and E.
A light truck tire load capacity is dependent on the size plus the load rating. All tires of a specific size and load range will have the same maximum load capacity. For example, LT245/75R16 tires have a load capacity of 2,205 lbs. for load range C and 2,623 lbs. for load range D.
Tires with a higher load capacity have that capacity at a higher inflation pressure. A load range D tire must be inflated to 65 lbs. per square inch (psi) to carry the maximum-rated load. The load tire pressure for a load range C tire is 50 psi.
Pressure and Ride
A load range D tire has the same load capacity as a load range C tire if it is inflated to 50 psi and will provide the same ride characteristics. Load range D tires only provide more capacity and a harsher ride if they are inflated to the higher-rated design pressure. A truck with load range D tires can be run with the lower air pressure for a better ride and inflated to full pressure when the load capacity is needed.
- Firestone Medium and Light Truck Data Book, page 65
- tire image by Orlando Florin Rosu from Fotolia.com