Replacement Tires for Tandem Axle Camper Using H 78-ST15

Question:

I have purchased an older camper trailer with H78-ST 15 tires on it. I dont seem to be able to find these particular tires anywhere. Trailer is dual axle and weighs around 6,000 lbs. What would be a good replacement tire. Thanks

asked by: Lee P

Expert Reply:

The HT78-ST15 is an older tire size designation. Stated in modern terms, the size would be ST225/75-15.

You can see our selection of tires and wheel/tire combos in that particular size by clicking the provided link.

I would recommend going with a radial tire, for better performance and longer life. This tire is available in three load ranges, C-2150 lbs, D-2540 lbs or E-2830 lbs. To determine the load range you need, determine the Gross Vehicle Weight Rating, GVWR (should be listed on the trailer somewhere). This is the maximum weight of the trailer plus all its contents. From this amount, deduct the fully loaded pin weight (for fifth wheel) or tongue weight (for bumper pull). Divide the result by 4. The number you get will represent the minimum capacity of tire you would need.

For example, your trailer weighs 6,000 lbs, and lets say it has a 6,000 lb capacity for a GVWR of 12,000 lbs. Lets also say the fully loaded pin weight is 3500 lbs. Subtracting the pin weight from the GVWR gives us 8500 lbs, which is 2,125 lbs when divided by 4. In that case, you would want to choose tires with a 2,125 lb capacity or greater.

For maximum tire life, keep your tires fully inflated to the maximum pressure listed on the tire sidewall. I have linked you to some articles with more information about trailer tires.

expert reply by: Mike L