What Are The Alpha-Numerical Codes On ST Tires?

Updated 04/17/2017 | Published 04/15/2017

Question:

I have a 1968 vintage Frolic trailer with wood paneling inside. The tires are ST225/75R15. Following this description is the following: LRE 10PR 117/112L. Does this mean I am to put 117 pounds of air pressure in the tire? This seems high.

asked by: Steve

Helpful Expert Reply:

No. The 117/112 is not the psi. It is the load index. The L is the speed rating of 75 mph. The load index is the rated load capacity for single and then dual tires on each side of the axle. 117=2833 lbs. The maximum psi should be listed on the tire sidewall and is also the recommended psi for the tires to operate.

For instance the Loadstar ST225/75D15 Bias Trailer Tire - Load Range D # AM1ST96 is similiar and rated for 65 psi max.

expert reply by: Jason S