What Should the Tire Pressure be for a 225/75-15 Trailer Tire with Load Range E Rating

Question:

I currently have ST 225x75Rx15 tires on my travel trailer, load range D. The weight of my single axle trailer, when fully loaded is approx 3,600 lbs. I currently maintain air pressure at 60 to 65 lbs. I have 2 questions for when I replace my tires. If I purchase the same size tire, load range E, based on the weight of my trailer, should I maintain tire pressure at 65 lbs, or increase it to the max of 80 lbs? Assuming I can maintain the tire pressure at 65 lbs, will the extra ply in the tires result in a stiffer suspension? I ask this question as things inside the trailer get pretty shaken on bumpy roads with my current tires.

asked by: Peter

Expert Reply:

If you install new 225/75-15 tires on your trailer or any trailer for that matter with a load range E rating like part # LHWL304 for example then you will need to fill them to the max psi listed on the sidewall which for this tire is 80 psi. This will allow you to retain the maximum weight capacity of 2,830 lbs per tire.

In regards to ply rating, this is no longer a viable metric in today's industry when comparing tires as tire manufacturers have gone to using lighter but stronger materials like Kevlar that provide the same strength that would have took several layers of materials years ago.

With that being said, the best 225/75-15 Karrier ST225/75R15 Radial Trailer Tire part # AM10303 which also has a load range E rating suitable for use up to 2,830 lbs per tire. FYI - this is a 10 ply tire.

expert reply by: Conner L