Weight Capacity of 5th Wheel Trailer Tires Required Accounting for King Pin Weight in GVWR


My 5ht wheel has a gross weight of 11,995 lbs. The tires supplied by the RV Mfg were West Lake ST225/75R15 LRE. It appears to me that each tire can carry 2830 lbs per tire for a total 11,320 lbs. Do you subtract off the hitch weight? Otherwise the math does not work, correct??


Expert Reply:

Technically you do remove the tongue weight of the trailer from the tire load capacity for the GVWR. The tires only need to be rated for the weight that is actually on the tire, so the axles can even be rated slightly lower. This however is not normally the case. In most instances the axles and especially the tires are rated higher than the required capacity for the GVWR.

For 15 inch tires the load rating of E is the highest rating we carry. The Westlake ST225/75R15 Radial Trailer Tire - Load Range E # LHWL304 are rated for the 2,830 lbs you referenced as well as speeds up to 75 mph. They also come with the best warranty of 5 years with 2 years roadside assistance included.

If you are looking to change your tires, you may want to consider the Goodyear Endurance ST225/75R15 Radial Trailer Tire - Load Range E # 724857519 which has the same load capacity but is made in the USA and rated for speeds up to 87 mph.

A final option is the Kenda Light Truck Tire K391M - 7.00-15 LT - Load Range E # AM10414 which has a higher load capacity of 2,403 lbs at 70 psi. This may give you a little more comfort because of the slightly higher capacity, but in my opinion it will not ride as well as the ST tires.

expert reply by:
Jason S

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