Tire pressure

[Rick Courtright]

Hi,

I use the door sticker pressure for starters:

Tires should be cold. That means they haven't been run in at least 3 hours. And haven't been sitting in the sun for those 3 hours, either! I usually check after dark or first thing in the morning. Then I add about 2 psi to the sticker--it's not unusual to have daily temperature spreads approaching 50 deg F around here at some times of the year, so I want to have the minimum on the sticker at the lowest temp I expect to encounter. I use one of these gauges, which can be eyeballed to 1/2 psi easily enough on the gauge (which is also about the limit of their accuracy):

https://www.ghmeiser.com/dial-gauges.htm (mine's the S60X)

Those numbers on the sidewall are "maximum cold inflation pressure." The vehicles I drive would shake your teeth loose at the 44 psi most passenger tires I see today use as their max.

As for that 26 psi problem on the Explorers back when, I'm not defending Ford's engineers for spec'ing such a low pressure for the type of vehicle and use, but it was probably enough, IF the driver always made sure that's what was in there, and never ran them low! One of those "...but it worked on paper" engineering problems? But too many people run around 2-5 psi lower than the sticker far more often than they realize (hence those stupid monitors?) Radial tires don't like that at all... and there's a cumulative damage problem that can creep up on the driver...

Rick C

 

[salaguinto]

I never do. I rely on the service station to rotate my tire every 10k miles, oil change every 6k miles, anti-freeze every 2 years. I turn in my leased car when it hit 30k miles or so. Never a headache.

 

[Bull Barrel]

Na$car is fussy about L/R tires because there may be a compound difference plus usually a diff in diameter. L side tires are smaller, helping the car turn. This is called, "stagger".

 

[The Norseman]

Thank you for starting this Topic.

It reminded me to check my Pickup Tires.

We are getting into the Cold Weather now,
and my tires were 4 pounds low.

My new Jeep Cherokee tells us pressure
so I just page to the monitor and look,
their Ok.

Thanks again.

 

[Fox Mike]

Another thing: Nitrogen vs ambient air. Imo nitrogen is a scam. The atmosphere is 78% nitrogen anyway. Ambient air is very slightly more sensitive than Nitrogen in terms of pressure variation due to temp. changes. Commonly air pressure changes by 1psi per 10deg F. of temp change. Pure nitrogen is pretty close to that. Again, unless you're screaming around a track at 200mph a couple psi one way or the other isn't going to make any difference in tire performance.

In SOLO we determined how to keep only the tread contacting the road. Place three equidistant chalk marks on each tire from the tread down to the sidewall. Drive the normal course and if the chalk was worn away on the sidewall we inflated and ran again till there was no wear shown on either the sidewall OR the very side of the tread. Now only the flat surface of the tread is touching the surface of the road. Sometimes this difference was a 1/4 pound of air one way or the other. In SOLO the car was rarely, if ever, run higher than second gear. The ride sucks but the tires perform great.

 

[mohavesam]

The TPI units on your wheels have been calibrated to the sensor computer, which lights up your dash warning lights, etc. Go with the door sticker (presuming you haven't been sold a different TPI when changing tires, etc. They are not exactly NASA-quality sensors, more like a dime-a-dozen.

Buy a good dial-type tire air pressure gauge and check them at rest - You're instantly a genius compared to 90% of the drivers out there. And tech your children well. Nothing good can come from a blowout-rolllover into oncoming traffic...

 

[blume357]

I run about 65lbs in my vehicle...... and yes... if the road is rough, which is just about everywhere here in S.C. because the number of cars on the road has doubled in the last 10 or so years and the S.C. highway dept. is about as 'poe' as you can get, I get a pretty rough ride... but If a rear tire is under inflated the back end will tend to wander.

 

[exavid]

I find 70% nitrogen works well in all my vehicle tires.

 

[Galaxiedan]

Im very strict about using 78% nitrogen in my tires

 

[Rick Courtright]

Im very strict about using 78% nitrogen in my tires

Hi,

Same here... it's worked for decades! I like that it's interchangeable between the cars and bicycles, I can still use my old metal valve caps, and a side benefit is it can be compressed to rather high pressures and used for cleaning stuff.

Rick C

 

[turd]

This is interesting, so many different opinions. I tend to think that the numbers in the door are for a fully loaded car, and mine almost never is, usually just me in it, and I'm big and all, but 35 PSI? I generally run about 32, and get a better ride, plus my tires usually run anywhere from 10,000 to 15,000 miles beyond the tire warranty. Works for me. I cannot understand how a tire shop can get 100% nitrogen in my tires. No matter how you do it, you have to mount the tires on the rims. There is a volume of plain old air inside the un-inflated, newly mounted tire. Therefore you need to inflate that tire, seat it on the rim, and somehow flush all the atmospheric air out of that tire while you replace it with 100% nitrogen. I'm sorry, but I ain't buyin' that.

Jeep Grand Cherokee. UpCountry springs, Bilstein shocks, rear sway bar, nearly new tires.

 

[daveg.inkc]

This is interesting, so many different opinions. I tend to think that the numbers in the door are for a fully loaded car, and mine almost never is, usually just me in it, and I'm big and all, but 35 PSI? I generally run about 32, and get a better ride, plus my tires usually run anywhere from 10,000 to 15,000 miles beyond the tire warranty. Works for me. I cannot understand how a tire shop can get 100% nitrogen in my tires. No matter how you do it, you have to mount the tires on the rims. There is a volume of plain old air inside the un-inflated, newly mounted tire. Therefore you need to inflate that tire, seat it on the rim, and somehow flush all the atmospheric air out of that tire while you replace it with 100% nitrogen. I'm sorry, but I ain't buyin' that.

Jeep Grand Cherokee. UpCountry springs, Bilstein shocks, rear sway bar, nearly new tires.

. I bet your Jeep rides good with these suspension parts. Every vehicle, car or truck needs a rear anti-sway bar. Unless rock crawlers. I just replaced front ball joints, bushings, tire rod ends, shocks, tires on my F-150 4X4. I added a Hellwig rear sway bar. Rides, drives great! I went with Monroe Re-Flex shocks. Mono tubes front. Twin tubes rear. Mono tube shocks are High Performance All gas charged. The best way to get long tread life, is to inflate tires to full tread contact with asphalt. Look at edge of tread to see black tire to lighter shade of tread

 

[bearman49709]

I mean really...given that the vehicle manufacturer has no way to know how I'm actually using their product or under what conditions, let alone what actual brand/type of tire I'm using to do it...who should I listen too...them, or the guys who made my tires?...Not that hard of a decision if ya ask me.
DGW

Do you think the tire manufacturer has any way to know how you are actually using their product or under what conditions, let alone what actual brand/ type vehicle your using to do it...who should you listen too... them, or the guys who made your vehicle?...Not that hard of a decision if ya ask me.

If you go to the tire manufacturer's web site they tell you to go by the vehicles recommended tire pressure.

 

[jeffmb]

I take the suggested pressure from the door jamb and add about 10%. This is done when tires are cold. Gives me a less "mushy" ride and improves mpg a bit. Never use the psi that appears on the tire itself. Also, is it me or do oil change places always way over inflate the tires?

 

[cleardatum]

all you need to remember, is: under inflation is the NUMBER ONE cause of tire failure. period.

 

[Rick Courtright]

Also, is it me or do oil change places always way over inflate the tires?

Hi,

Dunno if they all do, but a couple of local ones do that. They also tend to overfill the oil. Guess they figure tires can lose a little pressure before the next time you go in, and the engine can use a little oil, without causing some serious damage?

Rick C

 

[Mobuck]

"all you need to remember, is: under inflation is the NUMBER ONE cause of tire failure. period."

I AGREE 100%.
I have a tire here(1 of 4 excellent used load range E tires that I sold to my cousin)that had a catastrophic failure not long after he mounted them. His wife hooked up their travel trailer and took off w/o re-checking the pressure in the freshly mounted tires. Apparently this one either had a bit of a bead leak or was simply under-inflated by the tire shop. She hit I-80 with the Cummins (and most likely the tunes) crankin' and within 30 miles the tire absolutely disintegrated.
FWIW, I currently have at least 130 tires on the ground not including spares. I deal with a LOT of tires.