Are My Tires Overinflated?

[Excel]

i do my own tire checking,most tire shops have gauges that are in accurate
However,the tire pressure number to follow is not on the door but on the tire itself
and thats just a MAX number

Most tires that say for instance 44PSI seem to like 38-40 best for wear and ride comfort
I rotate every oil change and watch tire wear,too much on the edges and it needs
more air or too much wear in the center of the tread and it needs less air.
I am looking for even wear so my tires last max miles

 

[shiny]

bbhero, thank you for the kind thoughts. I will keep you in my prayers, also. CFIDS is similar to MS in that I look healthy but never know from one day to the next, or sometimes from minute to minute, what my capacity for exertion will be.

My tires' max psi is 44. The sticker on the door says 35. All Discount Tire stores offer free air checks to anyone who comes in, and free lifetime rotation and balancing if you buy your tires from them. The tech sets a machine to whatever psi he chooses then fills each tire until it reaches that psi and the machine beeps. Since I live across the street from DT and bought my tires from them, it's very convenient to stop in for monthly air pressure checks and rotations every 6K miles or so. Tires aren't cheap; I want them to last as long as possible.

 

[HTSS_TR]

Originally Posted By: shiny
bbhero, thank you for the kind thoughts. I will keep you in my prayers, also. CFIDS is similar to MS in that I look healthy but never know from one day to the next, or sometimes from minute to minute, what my capacity for exertion will be.

My tires' max psi is 44. The sticker on the door says 35. All Discount Tire stores offer free air checks to anyone who comes in, and free lifetime rotation and balancing if you buy your tires from them. The tech sets a machine to whatever psi he chooses then fills each tire until it reaches that psi and the machine beeps. Since I live across the street from DT and bought my tires from them, it's very convenient to stop in for monthly air pressure checks and rotations every 6K miles or so. Tires aren't cheap; I want them to last as long as possible.

No, he doesn't. He did because you didn't tell him what PSI you like for your car, so he look at recommended PSI for your car then set the pressure on the machine plus add few PSI to compensate for normal driving of several miles.

Next time when you drive your car to your local DT shop tell the tech the pressure your like for your car, he will do exactly what you tell him.

I like my front tires a little higher than rear, so i told the tech to pump the front to 38 PSI and rear to 36 PSI, the recommendation for E430 are 32 front and 34 rear, the tech just did it every time.

 

[jadatis]

Probably you dont even need the 35 psi , this is calculated for maximal loaded car, and mostly only you driveres and a little load.
Then even the 35 is general advice carmakers sometimes use and they dont even calculate anymore.
I am able to calculate a save pressure for you, but need weihts and speed of car , and the tire-specifications ( for wich you have to bend down to read them from sidewall, and that was not that easy for you I read).

But once you determined a pressure advice , lets asume the 35 is right, it is based on a outside tire temp of 65/68 degr F .
For warmer outside temp the pressure needs to be higher and automatically gets higher , and vice versa when colder lower pressure is measured and alright.
What is given is cold pressure and simply is when inside tire temp = outside tire temp .
when driven tire inside warmes up and so pressure rises, but also when sunshine on tire inside tire heats up.
When driving and using brakes often, also the heat of brakes is transported trought the rimms to the tire inside air and so also this heats up more.

The 38 psi is for the tires not a problem , only for comfort and gripp its less good, but still no disaster.
This asuming 35 is realy needed and no lower pressure would be calculated .

Greatings from a Dutch pigheaded self-declared tirepressure-specialist.
Peter

 

[Virtus_Probi]

Originally Posted By: Excel
i do my own tire checking,most tire shops have gauges that are in accurate
However,the tire pressure number to follow is not on the door but on the tire itself
and thats just a MAX number

Most tires that say for instance 44PSI seem to like 38-40 best for wear and ride comfort
I rotate every oil change and watch tire wear,too much on the edges and it needs
more air or too much wear in the center of the tread and it needs less air.
I am looking for even wear so my tires last max miles



This has been discussed to death...the advice above is bad, use what is printed on your car. You only care that the max pressure for your tire is above the pressure that is recommended for your car.

Shiny, I hear you on back trouble...I suffered from sciatica (car accident, rear ended hard in a sudden traffic stoppage) for about 10 years and there were plenty of times when bending over to tie my shoes or rinse my face off at a sink was just agony. I am lucky that my trouble cleared up and hope that, at the very least, you have less pain in the future.
I am glad to hear that you are on the lookout for shady mechanics, especially as a woman...my wife stopped at a seedy looking local place for a quote on new brake pads and they tried to sell her some massively expensive service that was not needed (probably new rotors, maybe even calipers). She said she had to think about it, and the guy pointed to our daughter and said it wasn't their fault if she got killed on the way home after my wife refused the critical service they warned her about. She was so scared she drove right to the dealer and they said, yep, you need new pads...some people are shameless in their greed.

 

[eljefino]

Also don't forget that the OP went somewhere wanting results. If she pulls in for air and no action is taken (or appearance thereof) she'll feel like she's getting brushed off.

 

[CapriRacer]

There are a lot of really good reasons why tire shops might use a higher pressure for firsthand leave their shop.

Certainly 3 psi is reasonably close the specified value.

 

[zzyzzx]

Originally Posted By: old1
Personally I always run my tires at least 2 or 3 lbs over sticker.


Same here.

 

[Darris]

2 or 3 PSI is a very minuscule difference, chances are if you bought 3 different tire pressure gauges they might disagree by 2 or 3 PSI. The ones at gas stations which live outdoors and take abuse can easily be off by 6 or 7.

In other words not a major issue to be 2 or 3 over.

 

[HerrStig]

Race teams use a tire pyrometer to measure the tread temp from side to side after a few laps. Too hot or too cold across the tread suggest the wrong compound is in use. They shoot for the same temp across the tread . Hotter in the center indicates over inflation, hotter on the edges indicates UNDER inflation. Hots spots in a particular area tells the tire guy there are alignment or tracking problems. It's a bit more scientific that "I always blow mine up to the number on the sidewall" Looking at the tread when it has a fine coating of dust on it, or looking at the footprint a wet tire leaves on a concrete floor can provide good information about how the tire will wear at a particular pressure as well.

 

[Boss302fan]

I would rather be 3 over then 3 under... If you do not check it yourself every week, then I would rather be at 38...

 

[totegoat]

In 3 months your tires will have self adjusted to 35, but DT will adjust them for you. A plate of homemade cookies are always appreciated.

 

[shiny]

Originally Posted By: totegoat
In 3 months your tires will have self adjusted to 35, but DT will adjust them for you. A plate of homemade cookies are always appreciated.


That's a great idea, totegoat.

The car is handling nicely at 38psi. My driving route, traffic and weather conditions are the same day in, day out. I always fill up at the same Costco. Yesterday's fillup calculation put MPG at 22.4 which is 1-MPG better than this car has ever gotten.

Thanks, everyone.