General rule for tire pressure?

When running the original size and load rating, I tend to run the max sidewall pressure. On our last trailer, we upgraded tires when we replaced them and ran 10 psi under the max. Current trailer has originals so run at max, but since we are nowhere near the GVWR for the trailer, have considered going with 10psi under.

Yes, The trailers I've run all had ST tires.

Sport45 wrote:

mowermech wrote:
There is, of course, the old-fashioned "chalk test".
Go to a large parking lot, make a chalk mark across the tread of the tire. Drive a few feet, then look at the mark.
If it is worn off mostly in the center, the tire is over-inflated.
If it is worn off mostly at the edges, the tire is under-inflated.
If the mark is evenly worn, the inflation is just right.

Same principle, but I use masking tape across the tread instead of chalk. I'll check it after driving a few miles and adjust the pressure until the wear pattern is slightly biased to the middle.

I kep trailer tires at maximum sidewall inflation pressure to minimize heat. In my experience, trailer tires are always replaced before the tread wears out anyway.

Well are you running ST's on your trailer that might be true, but with LT's that are rated to carry 3,042# ea. and the total weight on the 5er tires is only 9,000#. I run my trailer tires at 70 psi, because full contact equals better braking.

mowermech wrote:
There is, of course, the old-fashioned "chalk test".
Go to a large parking lot, make a chalk mark across the tread of the tire. Drive a few feet, then look at the mark.
If it is worn off mostly in the center, the tire is over-inflated.
If it is worn off mostly at the edges, the tire is under-inflated.
If the mark is evenly worn, the inflation is just right.

Same principle, but I use masking tape across the tread instead of chalk. I'll check it after driving a few miles and adjust the pressure until the wear pattern is slightly biased to the middle.

I kep trailer tires at maximum sidewall inflation pressure to minimize heat. In my experience, trailer tires are always replaced before the tread wears out anyway.

X2 to BenK's post!!

Those that always run the MAX, are looking for fast center wear, and very low traction when wet, or dry for that matter.

The tires on my TV have a capacity of 13,660#, the TV has a GVWR of 8,800#, I do tow over the GVWR, but nowhere near 13,660#. I adjust the pressure according.

I NEVER tow with more than 70 psi in the rear tires, most times right at 65 psi. I am carrying 5,500# on tires with an 80 psi, rating of 6,830#

enblethen wrote:
Door jamb numbers are for ride.
I would go closer to the maximum shown on sidewall. You could drop down a little but not more then 10 pounds.

Incorrect. That's a ridiculous recommendation. The tire sidewall on my F150 lists the max load pressure at 85psi. At 85 psi, each tire is rated to carry more than half of what my truck weighs. Why would I inflate them to that pressure? It would ride like it's rolling on rocks!

Inflate the tires to the load they will be carrying. The tire manufacturers don't have Load vs. Inflation Pressure tables for nothing...

The 'Rule of Thumb' is to start with the pressure on the door sticker (or the trailer's tire sticker) and adjust accordingly after verifying the weights on the tires.

Tire PSI is more to hole the tires shape than just holding up weight

Just 15PSI or so for most tires will 'LIFT' the vehicle corner's wheel
off the ground.

Higher than that is to maintain the tires shape for its duties. Stopping,
accelerating, directional control, shock absorber, etc, etc


Might be helpful showing what can happen to over inflated and under inflated

Did a quick search and posting several examples for others to also
see/learn about this, as this question is a constant

X2 on mower's chalk test. Add that some use masking tape. I always
check when there is a transition from wet to dry pavement and look
at the tread contact patch on dry


tireinflation


tireinflation tirecontact contactpatch

tireinflation triecontact contactpatch

underinflation tireunderinflation underinflationfailure

tireinflation overinflation underinflation

There is, of course, the old-fashioned "chalk test".
Go to a large parking lot, make a chalk mark across the tread of the tire. Drive a few feet, then look at the mark.
If it is worn off mostly in the center, the tire is over-inflated.
If it is worn off mostly at the edges, the tire is under-inflated.
If the mark is evenly worn, the inflation is just right.

Thanks everyone.

I'm set now. Just second guessed myself after reading the bit online....the internet can always be a dangerous place to pick up info!

I don't have time to worry about inflation depending upon the load. I always keep the tires on all vehicles inflated to the maximum pressure shown on the tire sidewall.

If I was inclined to change pressure based on load then I would use the charts found on the tire manufacturers website.