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Comparing 175/80-13 And 185/80-13 Tires


175 80r13D vs 185 80r13D trailer tires I would like to know if the tire size difference will affect tracking straight, more bounce or less bounce on the trailer? Will the height and the width difference made for better tracking or less? If running at less than weight capacity for example a lighter load should I run the tire pressure lower?I forgot to ask which one is likely to have less wobble at higher speeds. I am assuming it is the 175/80R13D. Due to the tire is not as tall. Do these tires have a speed rating, as they are not car tires but trailer tires. Some states have speed limits that are 80 miles an hour and some have speed limits of 55. Whoud a D load have less wobble and then a C load tire?


Expert Reply:

The size difference between the Kenda Karrier ST175/80R13 Radial Trailer Tire - Load Range D # AM10210 and a 185-80R13 tire is the diameter and the width. We don't have any radials in that size, so I'll compare to the similar Kenda Loadstar ST185/80D13 Bias Trailer Tire - Load Range D # AM1ST79. The 175/80-13 tires have a diameter of 24.1 inches and a width of 7 inches compared to the slightly larger 185/80-13 tires that have a diameter of 24.4 inches and a width of 7.2 inches.

The speed rating is based on the specific tire, not the size. The larger # AM1ST79 is rated M for 81 mph. The # AM10210 was recently adjusted to meet the 81 mph speed rating. In this case a bias tire is rated for higher speed but even with the Load Range D being the same category, the bias tire has a load capacity of 1,710 lbs at 65 psi compared to the radial at 1,610 lbs at 65 psi. You won't have tire wobble based on load capacity most of the time, but rather based on speed capacity and weather conditions. Bounce would be affected by load capacity as loaded a highter capacity tire may have better traction when loaded, but unloaded could have more bounce.

For your specific size of tire, I recommend the # AM10210 radial tire of the same size or the slightly smaller size of 175/80-13. I know it isn't the comparison you asked for with two radial tires, because I don't have the one size to judge from but in most cases the radial tire will win out because it can disperse weight better so it has less heat at highway speeds.

You should always run your tires at max psi weather loaded or unloaded for safety. Less tire pressure will cause a safety issue by reducing traction and increasing possiblity of blow out.

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