question about tire pressure

My tires say max 70 PSI. I've been running them at 60, is this bad? Should I be running them at full PSI? Or even less than 60?

 

you should be running them at 32psi or whatever it says on your door.

 

60psi?? Did your kidneys fall out yet?

Look on your door jam...I think the recommended is like 29psi. I run around 32psi....

Aside from the kidney part ...LOL 60psi can't be good for proper and long tire life/wear.

 

That's crazy to run that high Read the owner's manual or check the driver's door jam.

 

Pay no mind to what the door or owners manual say and put them at whatever you want to achieve your desired comfort, mileage, and needs. Running a 60 max tire at 50psi won't hurt it but I wouldn't go lower than 35-40 for everyday use because it's obviously a heavy duty LT tire and designed for higher than average pressure. I second the chalk test as a good rule of thumb.

 

+1 I run heavy duty LTs at 50 psi based on my tire guy's advice. Otherwise they'd really bring my MPGs down. My P rated winter Blizzaks "chalked out" between 36 & 38 psi.

Hi Chris.

EDIT: I air down the LTs for any real off-road use...then air back up.

 

That should be fine. Remember too that max tire pressure is set for tires that are at normal cool temp, not warm/hot from driving. Door jamb pressures are likely just for what tires come on the truck, so if you have different tires, etc, that likely doesn't even apply anymore.

My wifes 285's have a 60psi max, and I run them at 50-55 max.

 

I fail to see the logic in this statement....perhaps there is no logic. The recommended tire pressures found on the door jam or owner's manual apply to the majority of tires likely to be used on the vehicle. Certainly it makes sense to adjust these recommended pressures slightly according to conditions, preferences, comfort, etc.

I have NEVER, EVER seen published any recommendations to use the maximum pressure listed on the tire sidewall as a reference point. Only imbeciles and morons would over inflate their tires to be close to the maximum pressure on the sidewall.

 

This is good advice. The MAX pressure listed on the sidewall is what the manufacturer says is safe for the tire.

Now I have to add rickcrna to my ignore list!

 

Everything depends on the load rating. The trucks come stock with a p rated tires and most guys run Load Rated "D" or "E" for after market tires. Based on the load rating charts at discount tire unless you are pulling a trailer your tires will give you the best ride at around 35psi. I have 285/75/16 LR-D and I run them at 32 works great and run them at 20 offroad.

 

Max pressure of the tires is how much it will hold for max lbs

 

Search "Chalk Test"

 

If you want to blindly and obediently follow whatever a sticker on a door says then have at it. Some people like to use their brain to determine their own needs and desires.

I have LT's that are rated at 50psi max. I run them at 40 or 45 depending on my mood and air down to 18 when wheeling. I have reasons for choosing an LT tire and keeping it at those higher pressures.

 

There not "over inflated" until you've surpassed the pressure, or unless you're vehicle weight isn't enough to make good contact at that psi.

This imbecile has perfectly flat wear on all tires, on all 5 of my four wheel drives. My newest tires, minus the taco, are around 3 years old. I don't replace tires with the junk that comes stock. Maybe you do, but I run different load ratings. My wifes 285's are the only set that have a max of 60, and the 50 psi range is what seems to be working best with them.

I could also say that only an imbecile would run well under, and create the heat and friction needlessly. However, when you start ponying up the money for my tires, I'll run whatever pressure you would like me to.

 

A co-worker of mine had an oil change at a tire dealer. The tires that we had on our company vans had a max pressure of 60 PSI. The door sticker was 35 PSI. The service tech at the tire dealer told him he should be running 60 PSI in his tires because of the load that he carried and put that much pressure in them. Two days later a tire blew and he had a bad wreck. That was almost 20 years ago and he is still on disability. I had the same van and tires and always ran 35 PSI with no issues. Caution should be exercised when running the tires close to max.

 

You evidently do not have stock tires. The recommended tire pressure on the door panel is for stock tires, not C or D rated tires. Follow the tire recommendation, not the door recommendation. Too low of tire inflation causes too much side wall flex, the tire to over heat, and a possible tire failure. Follow what the tire says. By the way 60 is within the range of a 70 Max tire, but 32 to 35 is not. Always check and inflate tires when they are cold (before they have been driven any distance).

 

I used to be in the tire business. The reason that tire blew was because it had been run previously at too low a pressure and the tire was damaged from the heat that was generated. When the proper pressure was added the tire no longer could handle it because of prior damage. Max Tire ratings are not where the tire blows. Under federal law they have to be able to far exceed the max pressure marked on the tire. Most can handle a pressure nearly double the rating although it is not recommended to drive on them like that and if they have ever been grossly over inflated or under inflated they need to be replaced.

Tire ratings are where the tire preforms properly with the least amount of heat generated under proper load ranges. Too much Under or over inflation can cause the tire to break down internally and separate and or break the internal belts or cords. All street tires should be run within 5 Pounds of their recommended Max pressure for HYW use to insure safety depending on load. No load 5 under is fine. Heavy load max tire pressure. Over loaded 5 over will work, but it is never recommended to overload in weight a tire max load range.
Personally I always cold air my tires to the max plus as much as 5 on the front and the max on the rear even without a load. I have NEVER had a problem. In the summer sometimes I back that off because of Texas heat, but I never run them below 32, cold aired, on the HWY and they are rated a max 35 cold aired.

If you do off road and under inflate your tires for traction you should NEVER run those tires on the road again as they have been subjected to internal damage by the under inflation. Yes you may get away with it, but you may not also and the consequences could last a lifetime. You should have two sets. One for off road and one for HWY if you under inflate your tires for off road.

As for chalking tires I would not recommend it for HWY use if you are after safety and if the chalking puts you outside the parameters of the tire manufacturer recommended pressure. The manufacture of the tire does not say to chalk the tire for proper inflation. They give a tire pressure for the tire so I suggest it be followed within 5 pounds. Chalking will violate the warranty if you end up outside the recommended tire pressure.

If you have any questions about a particular tire and how low or how high you can inflate and remain safe and under warranty you should contact the tire manufacturer not the car dealer.

 

+1

Navy tests at Pax River determined that the speed at which hydroplaning will begin is directly proportional to the inflation pressure. This is without regard to fancy tread patterns... they help very little. All that matters is that the tread depth is less than the depth of the water (any tire will hydroplane once the water is deeper than the tread).

"Speed (in knots) = 9 X the square root of the tire pressure (in psi.)"
"Speed (in mph) = 10.4 X the square root of the tire pressure (in psi.)"

28psi = 55mph
32psi = 59mph
50psi = 74mph

Higher PSI, contrary to the myth, actually improves wet traction.

Door sticker inflation recommendations apply:
A - To the OEM tires only
B - Are a compromise between ride comfort, performance, tire life, and fuel economy.

 

LT tires are not P metric tires. Pressure requirements are different.

Read: David