Will There be Issues With Trailer Tires That Have Different Sizes and Load Ranges?

Question:

My boat trailer has ST185/80D13 tires with load range C. I need to buy a spare tire. I cant seem to find this exact size/combination. I can find ST175s with load range C, but cant find 185s with load range C. Can I use a ST175/80D13, load range C as a spare or would this cause a problem running a 185 on one side and a 175 on the other?

asked by: Lonnie H

Expert Reply:

When you have tires that are different sizes and load ranges, a number of issues can occur. They will be inflated to a different psi and the different sizes can cause uneven wear and a load which will not be level, possibly throwing off components of your suspension.

I recommend you have tires that are each the same size, be it ST185/80D13 Load Range D or ST175/80D13 Load Range C. If you wanted to go with ST185/80D13 Load Range D, we have the Loadstar # AM1ST79, which has a singe tire capacity of 1,710 lbs at 65 psi and speed rating of 81 mph. It fits 13" x 4-1/2", 13" x 5" and 13" x 5-1/2" wheels.

For a ST175/80D13 Load Range C, I recommend our most popular option, the Kenda # AM1ST51. It has a load capacity of 1,360 lbs at 50 psi and fits 13" x 4-1/2", 13" x 5", and 13" x 5-1/2" rims. I've attached links to review videos of each tire for you to take a look at.

expert reply by: Kyle S