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
Tim Plaehn has been writing financial, investment and trading articles and blogs since 2007. His work has appeared online at Seeking Alpha, Marketwatch.com and various other websites. Plaehn has a bachelor's degree in mathematics from the U.S. Air Force Academy.