I think most of us run the tire pressure that we believe, right or wrong, maximizes tread life. Then I think some of us will adjust it a bit for better mileage, or comfort, or performance, but maybe not, so lets see.

Question:
How much pressure do you generally run in the tires of your primary vehicle

Choices:
I run the manufacturer recommended pressure.
I usually run higher than the recommended pressure.
I usually run lower than the manufacturer recommended pressure.
I perform a chalk test on the tires to determine what the pressure should be, and I run that.

Question:
I adjust the pressure in my tires primarily to...

Choices:
maximize tread life
maximize performance
maximize comfort
maximize MPG
I run manufacturer recommendations, period.

 

I use the specs printed on the door label for both my and customer's vehicles in almost all cases. In mine, 30 psi front and rear. This pressure is for when the tire is cold; driving will heat them up and increase the pressure. If you check them hot and let air out, you may find them under-inflated later. There is room to play with it a little. For example, 3/4- and 1-ton trucks typically recommend 50-55 front and 80 rear. If it isn't going to be fully loaded, there is little advantage to max pressure in the rear and you can safely lower it so it doesn't ride like a buckboard wagon full of bricks. Some manufacturers' recommendations are unusual, for example, a Mercedes-Benz that was 29 front, 41 rear.

This message has been edited. Last edited by: egregore,

When I was in the police academy, they brought out two identical old police cars. One had 30 PSI in the tires, the other has 45 PSI in the tires. Then they had you drive both.

The handling difference was DRASTIC and it was an eye opener. The car with 45 pounds handled great, the car with 30 PSI handled terribly and hit a lot more cones and spun out a lot more often. This was a very good demonstration to young recruits about the absolute importance of keeping your tires properly inflated and not under-inflated.

I run a few pounds over the factory recommendation now. If my car calls for 32 pounds, I'll put 35 in. If it calls for 37 pounds, I'll put 40 in.

I just switched to running a few pounds over manufacturer recommendations....lol... No, I'm really going to, on bubbatimes experience... except during winter, I will lower them a bit for better traction...

answered for "best fit" of multiple choice.

realistically "all of the above" could apply depending on circumstances of necessity.

it is my understanding that all car manufactures choose a tire that provides the best "comfort" for the driver. it may not be the best tire for wear or MPG.

increasing tire pressure may provide better mileage, but may also ride stiffer than originally.

running manufacturer "recommended" pressures only help them sell you new tires. anyone running Z rated tires with low mileage rating? I bet the car handles great, rides great, but tires wear out before the rating.

chalk only works if you are driving the car to its limit, and the tire the only thing keeping you on the road.

tymll

john

I run recommended pressure of 40 psi on the road to 13 psi on trails. Somewhere in between that for other circumstances

Soooo, I'm all over the place.

My preference is not in your poll. I use the pressure that maximizes safety.

Somewhere in between the tire manufacturer's max pressure and the car's recommended pressure. Generally, I start at the tire max pressure, drive around a while, and reduce pressure some to balance performance and comfort.

I just topped up all the tires on my Camry. For a passenger car, I generally just fill to mfg specs. If it was a specialized vehicle however, like a sports car or off-road, I am not above fine-tuning tire pressures for specific purposes.

What's scary is the number of people who think the correct spec is the max pressure embossed on the tire itself.

The rules may differ slightly with the newer cars with ABS, traction control, automatic pressure monitoring, etc.

My friend just bought a new car and I'm amazed at how complex the systems have become.

A lot is connected to tire pressure, from braking action to steering; even hydroplaning.

The tire will hydroplane at 9X the square root of the tire pressure. Low pressure may yield a lower speed, but low pressure accounts for more blow-outs than anything else, as it leads to excess sidewall flex, heat buildup, and tire failure.

The recommended pressure range exists for a reason. It's not arbitrary, and it's been well tested to be established at that value.

I generally take the pressure on the B-pillar and double it.

Max psi for max load is listed at 40psi... so I run 38-39. 2012 Nissan Altima. Do the same for my wife’s accord too.

quote:

Originally posted by sns3guppy:

The tire will hydroplane at 9X the square root of the tire pressure.

not doubting you, but, I don't understand how this equation is used in real life, if say I change my pressure by 4 lbs.
Where does the equation come from? Does it vary with surface type or slickness?

For you guys that run near max pressure, do you compensate for the rise of pressure when the tire/air heats up?

quote:

Originally posted by kkina:
What's scary is the number of people who think the correct spec is the max pressure embossed on the tire itself.

Sometimes it is. Even a blind pig finds an acorn every once in a while. Agree the door sticker is a better starting point, but they aren’t always different.

quote:

Originally posted by slosig:

quote:

Originally posted by kkina:
What's scary is the number of people who think the correct spec is the max pressure embossed on the tire itself.

Sometimes it is. Even a blind pig finds an acorn every once in a while. Agree the door sticker is a better starting point, but they aren’t always different.

Correct, but I was referring to people who think it's always max pressure.

I once test drove a jeep, and was dismayed at how erratic and bumpy the suspension was. I then found out he had inflated to max pressure, something like 50psi. I reset them to around 30, can't remember exactly, and it then handled fine.

quote:

Originally posted by Nismo:
For you guys that run near max pressure, do you compensate for the rise of pressure when the tire/air heats up?

The door jamb sticker is the COLD pressure, so no need to take into account the hot pressure. Just make sure your COLD pressure is at least what the door jamb says, and you should be rather safe.

If the tire says 45 PSI max, then that is cold. The tire manufacturer knows that tires heat up and increase pressure, and they take that into account. Their design likely has a blow out pressure 75-100% over recommended values, so the 45 PSI max tire is not likely to blow until it gets up over 70-80 PSI.

quote:

Originally posted by radioman:

quote:

Originally posted by sns3guppy:

The tire will hydroplane at 9X the square root of the tire pressure.

not doubting you, but, I don't understand how this equation is used in real life, if say I change my pressure by 4 lbs.
Where does the equation come from? Does it vary with surface type or slickness?

Look it up yourself, but it's evident that you missed the point.

Manufacturers spec for me.