Tire Info

Balance and use metal stems!!

Tires will heat up at speed and increase in pressure. All is normal as the tire makers take all this into consideration when the tire was designed.
I've seen my 80 psi E tires on my equipment trailers when carrying loads go to 92-94 psi on a hot 100+ degree day and interstate speeds after a long run.

Robert812 wrote:
Hi all, got my new tires ST225/75r15d. they are rated for 65psi for weight of 2540 per tire x4. Now all I read is never fill to max. Mr Big-o tells me the tire is make for 65 psi max.(cold) so going down the heated highway my tires go to 72psi. I really don't know. now on my 2004 Lincoln Navigator they want P275/65R18 and the tire is 44psi max, so fill to 35. is suv tires not like the st tires? they make room for heat, but not the trailer. what is the thinking here?
thanks and happy camping.

Cars, pickup trucks and SUV's are done differently than trailers. Those vehicles (meaning not trailers) have a tire placard that can be trusted, so use the pressure listed there - assuming you are towing within the limitations published by the vehicle manufacturer.

Trailers on the other hand have demonstrated that the manufacturers aren't consistent and frequently under-tire the vehicle - which is why the standard answer is to inflate the tires to the max.

A better answer can be obtained by actually weighing the vehicle (in its worst possible configuration). What you are looking for is the worst possible tire load any tire will see, so that also means weighing it tire by tire (or compensating for the fact that you didn't).

amxpress wrote:
You have passenger car tires on your trailer. OUCH!
Replace them ASAP with a quality ST radial tire. Do not use bias tires.
The most popular ST tire is made by Maxxis. There are other ST tires that might be worth checking out. Hercules, newer Carlisle RH, and Tow Max. All of these are ST tires that come in your size.
Be sure to have them balanced, too.

Where is the Maxxis most popular? Just asking?

I'd put 44lbs in the Lincoln and 65lbs in the trailer tires, they will will run cooler at max inflation.

they are an 8-ply tire so they tell me. I know the tires will hold the trailer well. Not needing the ply, would like to know about the PSI. is the ST225/75R15D
rated higher for the tire say 80psi so they rate fill 65psi(2540)

You are not going to find 7-ply tires, bias or radial ply, in sizes for your trailer.

Most radial tires will have 1 or 2 radial plies, and two plies in the belt under the tread. Three at the most. Bias ply tires will usually have two plies, and usually no belt.

Ply counts are an obselete way to describe tire capacity, from the days of cooton cord tires when a stronger tire needed 4,6,8,12 plies of cotton cord. Synthetic cord materials put an end to that.

A numerical "ply rating" then followed in attempt to relate carrying capacity to something familiar from the past. Your will still see the terminology used, unofficially, but the replacement descriptor today is Load Range. Load Range C approximates to "4 ply rating", D to "6 ply rating" roughly, but both classes will be constructed today with just two plies of cord in the tire body.

Tires also now carry yet another rating, load capacity, which puts together the factors of size (bigger tires carry more) and design (Load Range) or the obselete Ply Rating. These are numeric, numbers like 92, 96, 98, 102, 112, 118 and so on.

Hi all, got my new tires ST225/75r15d. they are rated for 65psi for weight of 2540 per tire x4. Now all I read is never fill to max. Mr Big-o tells me the tire is make for 65 psi max.(cold) so going down the heated highway my tires go to 72psi. I really don't know. now on my 2004 Lincoln Navigator they want P275/65R18 and the tire is 44psi max, so fill to 35. is suv tires not like the st tires? they make room for heat, but not the trailer. what is the thinking here?
thanks and happy camping.

dave54 wrote:

Robert812 wrote:
Hi everyone and thank you for your help. My KZ is a 1997 Sportsman weighting at 5600 dry. (wow) anyway I called Big-o and found some tires. Commodore Radial ST st205/75R15C Ordered 5 tires. Now I know I'll be safe on the road. Again thanks for all your help. Hope to see everyone camping. Be safe

load range D or E would be better. And have them put in metal valve stems.

x2 on going to a greater load range. C's just barely cover what I expect to be your fully loaded weight without allowing for a safety margin.

Robert812 wrote:
Hi everyone and thank you for your help. My KZ is a 1997 Sportsman weighting at 5600 dry. (wow) anyway I called Big-o and found some tires. Commodore Radial ST st205/75R15C Ordered 5 tires. Now I know I'll be safe on the road. Again thanks for all your help. Hope to see everyone camping. Be safe

Double check with Big O and check to seee if those tires have the nylon cap. I don't think they do. ST tires that have the nylon cap Include Carlisle Radial RH, Towmax STR, and Westlake ST tires and oh....Maxxis ST trailer tires.