tire pressures

[hpracing10]

2003 halfton silverado Z71- I have Load range E tires on it, so they are 10 ply. The sidewall calls for no more than 80 psi cold, but of course we all know not to run tires at the rated pressure as that is wayyyyy too much. I have them at 45 psi cold, and the centers seem to be wearing out faster than the outside edges. they are all terrain tires, actually they are Hercules Terra Trac A/W tires. With 45 psi they are squatting down pretty good and the whole surface of the tire is touching the ground, not up on the edges or anything. Why are they wearing faster in the center than the outsides? I don't really want to go any more lower because I think they are already low enough, if not too low.

By the way, the truck has been kept properly aligned for the life of the tires and they were balanced when new and are still balanced fine. I rotate them every 5K miles also. The tires have around 35K miles on them of about 85% highway and 15% off road. They look like they could still go another 20K but just want to figure out how to make them wear evenly.

 

[Chris Meutsch]

What's the door plate pressure specify? I run my tires 3-4lbs. over the plate rating for better wet traction and slightly better gas mileage.

 

[hpracing10]

The side of the drivers door says to run them at 35psi all around..I wasn't sure if this was true for higher load rating tires though, The tires that came on the truck from the factory were load range C, 6 ply. I just wasn't sure if you are still supposed to run 35psi, even with a heavier-duty tire. Thanks for your advice i'll try dropping the pressure and see if that helps.

 

[Drew99GT]

If you're wearing out the centers, they're overinflated for the weight/load the tires are seeing. If you're carrying a big load, THEN inflate them more.

 

[CapriRacer]

I am going to guess you've gotten caught up in the "LT" vs "P" thing. Your tires say "LT" in front of the size (That's for sure!), while your vehicle tire placard says "P" in front of the tire size (This is a guess on my part.)

So you need to check to see if this is correct.

If that is not correct, what tire sizes are dealing with - both the placard and what's on there now?

And I think you are wrong about the original tires being Load Range C. So it's really important that you carefully record what's on the placard.

 

[hpracing10]

The tires on the truck now are the stock tire size, they are LT265/75R16. That is the same size tire that came on the truck from the factory. The inside of my door just states that the tire size from the factory is 265/75R16 but I know that the factory tires were not Load Range E, which is what I have on now. Should I stick with 35 psi like the inside of the door says, or do I need to run more pressure because it is a heavier duty tire? I don't see a problem running 35psi like it calls for, basically I just wanted to know if I needed to run more because of the heavier tire I have on it now as compared to the lighter duty tire that came on the truck when I bought it new. Thanks

 

[Chris Meutsch]

If you were running them at 45psi then yes, the centers would run out sooner. Drop it to 39psi and see how things go.

 

[OVERKILL]

Originally Posted By: hpracing10
The side of the drivers door says to run them at 35psi all around..I wasn't sure if this was true for higher load rating tires though, The tires that came on the truck from the factory were load range C, 6 ply. I just wasn't sure if you are still supposed to run 35psi, even with a heavier-duty tire. Thanks for your advice i'll try dropping the pressure and see if that helps.


If it came factory with P-series tires, why do you have LT load range E tires on it?

 

[CapriRacer]

Like Overkill said, your truck came with "P" type tires.

But I suspect the answer to your question (what pressure should you run to get the tires to wear evenly) is:

There isn't a proper pressure, because the tire were NOT designed to wear evenly across the tread face. They were designed to have some off road traction and the way they did it is to use a tread width that is too wide - and put lugs in the additional width.

The best information we have is that you ought to be running 50 psi. That gives you the same load carrying capacity as the original tires had at the placard pressure.

 

[38sho]

tires wear in the middle for two reasons

higher pressures

or too wide of a tire for the wheel.....

as you try to mount a wider tire on the same width wheel, the tire begins to balloon up so to speak, the sidewalls gets closer together and the top(tread) part of the tire begins to buldge up

I would sell these tires if you are having such a problem with them. Get the proper tires for the truck, and run the recommended air pressures....

the difference in width between a P and a LT could be a lot. They might both say the same numerical values, but that doesn't mean they share the exact dimensions.... even a P265-75-16 can vary in physical dimensions from models from the same brand to different brands. I.E. a Goodyear highway tread tire might not be the same size as a Goodyear MT/R, and none of those might not be the same size as the same numerical size but say in Michelin or Firestone.

line up 5 differen 225-45-17's next to each other, and none of them will be exactly the same.... In fact I've seen some that were so much larger, I had to check the tire sizes on the sidewalls about 5 times to make sure my eyes were working properly

that being said, higher pressures won't nessecarily cause the middle of the tire to wear, especially if you have a lot of weight pushing down on the tire. We have a fleet account with a local TV news company, and I run the placard recommended 80psi on the tires and have never seen them wear prematurely in the middle. Some trucks with the same setup that don't carry a heavy load, with the same tires, same size, same pressures, same wheels, do exhibit wear in the middle.......

do you carry a lot of weight normally? if you don't then ditch those tires ASAP, they probably ride much worse, don't balance as good, are noisey, more expensive, and the number 1 problem is they are much heavier! You would be suprised how much performance you will gain when you drop 20lbs or more off of each tire on a truck....

 

[CapriRacer]

Originally Posted By: 38sho
tires wear in the middle for two reasons

higher pressures

or too wide of a tire for the wheel.....



I would also add "If they are mounted on the rear of a RWD."

I don't know exactly why this is so (I have some plausible conjectures), but I have lots of experience that says this is so.

On the other hand, front tires of a RWD (the steer position) tends to wear in the shoulders - and I think it is obvious why that is so.

Which brings me to rotation. Rotating tires on a RWD will even out these 2 tendencies and the results is slightly longer wear life.