Comparing Tire Load Range Ratings for 25 Foot Sailboat Trailer

Question:

I have a 25ft sailboat, that sits about 10-11 ft off ground on double axle trailer. Boat and trailer weigh 5-6k lbs. What is the appropriate load range? Does D give higher margin of safety? What would be drawback to D vs C?

asked by: DJ

Expert Reply:

A load range D tire like the Provider ST205/75R15 Radial Trailer Tire - Load Range D # TR20515D has a higher load capacity than a load range C tire as well as a higher ply rating, so firmer sidewall. This does give a higher level of safety due to strength and the only drawback is a stiffer ride when there is not the weight on the trailer. An empty trailer will ride slightly more rigid.

The size of tire will change the load range. For instance, the above tire is rated for a maximum load of 2150 lbs at 65 psi and speeds of up to 81 mph. Trailer tires should always be inflated to their max psi like this when inflated cold for that proper rated capacity.

To compare, the Loadstar ST225/75D15 Bias Trailer Tire - Load Range D # AM1ST96 is rated for 2540 at 65 psi and has a speed rating of 65 mph max. The Loadstar ST205/75D15 Bias Trailer Tire - Load Range C # AM1ST92 is rated for 1820 lbs at 50 psi and speeds of up to 65 mph max.

expert reply by: Jason S