Can I Run My ST225/75R15 Load Range E Tires At a Lower PSI Rating For Lighter a Trailer

Question:

I have 225 75R 15 load range E tires on my cargo trailer. What pressure should I run, considering the loaded trailer weighs is close to 3800 pounds. The max load indicated on the tire is achieved at 80 psi. Is that too high considering the relatively light load of less than half the rated capacity?

asked by: John

Helpful Expert Reply:

That's a great question!

We always recommend sticking to the psi rating indicated on the sidewall unless your specific tire manufacturer has a chart listing showing what psi you need for different loads. Could you get by with a lower psi rating? Yes, but if the manufacturer hasn't tested and listed it out then your tires will have an unknown weight capacity and you'll be more susceptible to a blow out.

For example, the Karrier ST225/75R15 Radial Trailer Tire - Load Range E # AM10303 is rated for 2,830 lbs at 80 psi. This means for a single axle trailer the tires can handle a combined weight of 5,660 lbs. This will feel a bit stiff for your 3,800 lb trailer but if you lower the psi your tires could eventually fall under that 3,800 lbs and they will be struggling to keep up.

I tend to be a bit more cautious and play it safe especially when it comes to load ratings and what can happen when you're traveling down the road.

expert reply by: Jon G