Tires over pressure.

[daShadow]

2 or 3 weeks after getting my new BS I was scrolling through some of the dash screens and noticed the tire pressure readings were way high, 47 & 48 psi on all tires, hadn't really paid any attention to it before. Went to Discount Tire for free tire check and they said the readings were correct. He lowered them all to I think 35 psi and said my tires were rated for a max of 44. No one had touched the tires since I got it, so it came from the dealer that way. Must admit the ride was a little smoother after changing pressure.

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[Jmuns]

They over-inflate them at the factory for transport. Sticker for the car says 33psi for the tires.

 

[daShadow]

They over-inflate them at the factory for transport. Sticker for the car says 33psi for the tires.

Didn't know the factory did that, dealer should know that and check during pre-delivery. Oh well, no harm done. The tires were hot so Discount probably added a couple of # to sticker pressure.

 

[V8 Yankee]

The sticker pressure is for maximum tread life. If you are towing, have cargo or passengers adjust upwards to compensate. Driving without any of the above the temp can easily go up 5 psi or more depending on the temperature. Exceeding max psi on hot days is really the biggest concern, especially with passengers and cargo. Personally I run 5psi over cold pressure (33psi). I sacrifice a little ride quality and treadlife but gain a little mpg. Its kind of a tradeoff. I agree though on the factory psi being pumped a little high. Ford has a QC issue with that, oil levels and other items that slip through factory and dealer prep.

 

[Rockboz]

As a side note, my MINI Cooper S sill plate has 34psi, if planning on driving at 100 mph, 36psi

 

[sajohnson]

As a side note, my MINI Cooper S sill plate has 34psi, if planning on driving at 100 mph, 36psi

I've seen advisory labels like that -- mostly on European cars.

There may be three psi specs: 1) Normal (for the US) speeds and light/moderate load, 2) high speed (say over 100 mph) or heavy load, 3) both high speed AND heavy load.

Those labels are a reminder of how seriously they take driving in some other countries.

 

[SBGrad]

On the lot when I picked up the car the tires were over 40 psi ( noticed when I took it for a test ride). When we went inside to sign the paperwork I told the SA they needed to bring the tires to recommended pressure-- which they did.

Had a couple oil changes at same dealer and they've always given it back with correct pressure.

 

[Janet]

Hi, there. I have a question about proper tire pressure. The recommended cold PSI on the door is 33, but I read in my manual that if you drive it more than 3 minutes or over a mile the tires become hot and the tire pressure should be increased by 4 PSI. I check my tires at a service station that is more than 3 minutes and 1 mile away every Saturday. So, should I have them make sure the tires are inflated to 37 PSI? I just want to be sure I'm taking the best care of my tires. Thank you for your help! Janet

 

[Bloomsey]

Hi, there. I have a question about proper tire pressure. The recommended cold PSI on the door is 33, but I read in my manual that if you drive it more than 3 minutes or over a mile the tires become hot and the tire pressure should be increased by 4 PSI. I check my tires at a service station that is more than 3 minutes and 1 mile away every Saturday. So, should I have them make sure the tires are inflated to 37 PSI? I just want to be sure I'm taking the best care of my tires. Thank you for your help! Janet

I would inflate them to 33-34 psi when cold. They will gain a little psi when driving especially with hotter temps so it will get up to 37/38 potentially which is still well within acceptable psi. If you start with them inflated to 37, then they will get up to 42 psi when driving which may be too high and create issues.

 

[Mark S.]

Hi, there. I have a question about proper tire pressure. The recommended cold PSI on the door is 33, but I read in my manual that if you drive it more than 3 minutes or over a mile the tires become hot and the tire pressure should be increased by 4 PSI. I check my tires at a service station that is more than 3 minutes and 1 mile away every Saturday. So, should I have them make sure the tires are inflated to 37 PSI? I just want to be sure I'm taking the best care of my tires. Thank you for your help! Janet

Check the pressures before you start driving. If a tire is three psi lower than recommended when cold, then simply drive to an air source and add three psi to whatever it's reading when you get there. The next day check the pressure again when cold. It should be right on.

 

[RushMan]

I had a slow leak in one of my Falken AT3Ws. Took it to local Goodyear, they couldn't find a leak, but after remounting , no more leak. They did set all my pressures to 40-41 psi though. I brought them back to 33 when I got back home. I'm not impressed that the Goodyear service center did that. And wow, did my Badlands ever ride rough with the tires at 40 psi !

 

[sajohnson]

I had a slow leak in one of my Falken AT3Ws. Took it to local Goodyear, they couldn't find a leak, but after remounting , no more leak. They did set all my pressures to 40-41 psi though. I brought them back to 33 when I got back home. I'm not impressed that the Goodyear service center did that. And wow, did my Badlands ever ride rough with the tires at 40 psi !

From what I've read over the years, here and elsewhere, it's very common for tire shops to overinflate tires. A few possible reasons are:

* Ignorance. Even though they have just "one job" they often hire people with little knowledge and do not train them well.

* Laziness. It's easier to just inflate tires to the max pressure on the sidewall than look up the correct pressure (or check the door label).

* Generally speaking, a lot of people think "more is better" when it comes to many things. Of course that's often not the case.

People hear that low pressure may contribute to a blowout. True, but that does not mean that adding 50% or more to the mfr recommended pressure = good.

Auto and tire mfrs recommend against excessive pressure as well -- it just is not emphasized as much. Excess tire pressure can cause:

* A smaller contact patch
* Longer emergency braking
* Lower maximum G-force when cornering (more responsive steering is deceptive).
* Tramlining
* Greater risk of punctures
* Greater chance of blowouts from impacts
* The rougher ride Russ mentioned

It's disappointing that tire shops continue to overinflate tires.

 

[NMhunter]

The sticker pressure is for maximum tread life.

I was told in driver's ed years ago that the sticker pressure was for most comfortable ride. I tend to believe that is true. It could also be for better off road traction. I find it interesting that my wife's Hyundai Tucson lists the pressure at 35 psi. The weights of the two cars are very close. I once overinflated the tires on my Karman Ghia and wore out the center two inches on the tires, but got 40 mpg.

My son was talking on the phone while filling one of my boat trailer tires, and overinflated it. The tread separated after about 70 miles on a hot day.

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