Tire Pressure

I apologize for the crosspost...

I have a pair of Neons, an '03 and an '04, and the tire pressure was getting
low in the '03. I've never checked it since we've had it, but it was reading
about 27 psi at each wheel. The door sticker reads 32 psi but the tire
sidewall reads a max of 44 psi. So I'm wondering what should the pressure be
set at? In years past, I always went about 4-6 psi less than the max listed
on the tire to account for temperature changes, altitude, etc. So I ended up
going with 38 psi all around. The ride is much firmer and I'm wondering if
it's meant to be at 32 psi after all.

Any suggestions?

Thanks,
NG

NG wrote:

> I apologize for the crosspost...
>
> I have a pair of Neons, an '03 and an '04, and the tire pressure was getting
> low in the '03. I've never checked it since we've had it, but it was reading
> about 27 psi at each wheel. The door sticker reads 32 psi but the tire
> sidewall reads a max of 44 psi. So I'm wondering what should the pressure be
> set at? In years past, I always went about 4-6 psi less than the max listed
> on the tire to account for temperature changes, altitude, etc. So I ended up
> going with 38 psi all around. The ride is much firmer and I'm wondering if
> it's meant to be at 32 psi after all.
>
> Any suggestions?
>
> Thanks,
> NG

I could be wrong about this, but my view has always been that automotive
manufacturers are paid to engineer these things to a specification
exacting enough to provide the best longevity at the least cost with the
tools and technologies they are given (permitted?) to use. With this in
mind, they're not going to cheap out on tire research when that's a very
extremely important aspect of the overall vehicle. They're going to do
the research, do the stress testing, do the road testing, and they're
eventually going to get to the right tire pressure that permits for things
like road temperature, vehicle weights, etc., and therefore all you need
to do is fill the tires to the point they tell you to. MY far-from-expert
advice would be not to second-guess an engineer who probably earns a hell
of a lot more than any of us do, and to trust what they tell you is
appropriate for your vehicle.

OTOH, if you're an automotive professional with years of training and very
expensive education in the matter, you could probably customize every
little nuance of your ride to fit your driving style, but what they came
up with is pretty much guaranteed to work for all sane driving styles.

FWIW, I fill mine to 32 psi. Mine hold air with no problem. About every
6 months or so I have to put just a couple psi in, but not much. If
you haven't lost but 5 psi over a year and a half, that's not bad at all.
Just put it back at 32 and keep a regular check on it.

As for altitude, even at sea level we're only under 14 psi or so, so I'd
imagine at 50,000 feet it would only drop 7 psi. We can't even get above
10,000 without the need for oxygen, and not much higher before we need
pressurization, but I don't see altitude really affecting automotive tires
to the point you need to concern yourself with it.

Which also makes me wonder if you even need to worry about road
conditions: do a simple test... take the psi reading before you go
driving, and then take the family on a nice scenic drive or something
(good 30 minutes or so at highway speed should do the trick) and when you
get back home, check the pressure again while the tires are still warm. I
doubt you'd see more than 4 or 5 psi difference, although it's a guess.

Again, I'm no expert. HIH.

CJ
--
THIS POST ORIGINATED FROM USENET, *NOT* ANY WEB-BASED FORUM! IF YOU ARE READING
IT FROM A WEB BROWSER SUCH AS INTERNET EXPLORER OR NETSCAPE, THEN YOU ARE NOT
READING THE ORIGINAL POST AND YOU SHOULD LEARN ABOUT "USENET" FROM
http://www.ibiblio.org/usenet-i/usenet-help.html

NG wrote:

> I apologize for the crosspost...
>
> I have a pair of Neons, an '03 and an '04, and the tire pressure was getting
> low in the '03. I've never checked it since we've had it, but it was reading
> about 27 psi at each wheel. The door sticker reads 32 psi but the tire
> sidewall reads a max of 44 psi. So I'm wondering what should the pressure be
> set at? In years past, I always went about 4-6 psi less than the max listed
> on the tire to account for temperature changes, altitude, etc. So I ended up
> going with 38 psi all around. The ride is much firmer and I'm wondering if
> it's meant to be at 32 psi after all.
>
> Any suggestions?
>
> Thanks,
> NG

I could be wrong about this, but my view has always been that automotive
manufacturers are paid to engineer these things to a specification
exacting enough to provide the best longevity at the least cost with the
tools and technologies they are given (permitted?) to use. With this in
mind, they're not going to cheap out on tire research when that's a very
extremely important aspect of the overall vehicle. They're going to do
the research, do the stress testing, do the road testing, and they're
eventually going to get to the right tire pressure that permits for things
like road temperature, vehicle weights, etc., and therefore all you need
to do is fill the tires to the point they tell you to. MY far-from-expert
advice would be not to second-guess an engineer who probably earns a hell
of a lot more than any of us do, and to trust what they tell you is
appropriate for your vehicle.

OTOH, if you're an automotive professional with years of training and very
expensive education in the matter, you could probably customize every
little nuance of your ride to fit your driving style, but what they came
up with is pretty much guaranteed to work for all sane driving styles.

FWIW, I fill mine to 32 psi. Mine hold air with no problem. About every
6 months or so I have to put just a couple psi in, but not much. If
you haven't lost but 5 psi over a year and a half, that's not bad at all.
Just put it back at 32 and keep a regular check on it.

As for altitude, even at sea level we're only under 14 psi or so, so I'd
imagine at 50,000 feet it would only drop 7 psi. We can't even get above
10,000 without the need for oxygen, and not much higher before we need
pressurization, but I don't see altitude really affecting automotive tires
to the point you need to concern yourself with it.

Which also makes me wonder if you even need to worry about road
conditions: do a simple test... take the psi reading before you go
driving, and then take the family on a nice scenic drive or something
(good 30 minutes or so at highway speed should do the trick) and when you
get back home, check the pressure again while the tires are still warm. I
doubt you'd see more than 4 or 5 psi difference, although it's a guess.

Again, I'm no expert. HIH.

CJ
--
THIS POST ORIGINATED FROM USENET, *NOT* ANY WEB-BASED FORUM! IF YOU ARE READING
IT FROM A WEB BROWSER SUCH AS INTERNET EXPLORER OR NETSCAPE, THEN YOU ARE NOT
READING THE ORIGINAL POST AND YOU SHOULD LEARN ABOUT "USENET" FROM
http://www.ibiblio.org/usenet-i/usenet-help.html

Circuit Breaker wrote:

> > I have a pair of Neons
> > I ended up going with 38 psi all around.
> > I'm wondering if it's meant to be at 32 psi after all.

> my view has always been that automotive manufacturers are paid
> to engineer these things ...

If you're a tire, you don't really care what car you're on. You care
if you're mounted on the correct-sized rim, and then you care about
how many pounds you're being asked to carry.

It's actually a pretty dumb thing for car makers to put the tire PSI
on the door jamb. Ok, well, they do know what tires they put on the
car from the factory, so that's really the only *correct* situation
where the door-jamb PSI spec is valid. Other than that, once you
start putting on different tires (and different sizes) then the tire
makers should have specs as to what a given tire should be pressurized
to for a given weight to obtain the correct rolling profile.

You need enough pressure so that the tire doesn't deform a lot
(flatten-out) as it turns. That's a function of the weight of the car
(and all cars are different). Too much air results in too little
contact patch surface (and a hard ride, and too much center wear, but
probably great fuel economy).

Most passenger car tires know they're going to be carrying (3700 / 4 =
) 925 lbs, so you'd think that instead of the ridiculous "max
pressure" rating on a tire that there'd be *the correct freeking PSI
rating* for 1000 lbs load.

What ever happened between Ford and Firestone's SUV tires? Was it
proven that Ford's door-jamb rating was not correct for the particular
tires that were blowing out on the highway?

Circuit Breaker wrote:

> > I have a pair of Neons
> > I ended up going with 38 psi all around.
> > I'm wondering if it's meant to be at 32 psi after all.

> my view has always been that automotive manufacturers are paid
> to engineer these things ...

If you're a tire, you don't really care what car you're on. You care
if you're mounted on the correct-sized rim, and then you care about
how many pounds you're being asked to carry.

It's actually a pretty dumb thing for car makers to put the tire PSI
on the door jamb. Ok, well, they do know what tires they put on the
car from the factory, so that's really the only *correct* situation
where the door-jamb PSI spec is valid. Other than that, once you
start putting on different tires (and different sizes) then the tire
makers should have specs as to what a given tire should be pressurized
to for a given weight to obtain the correct rolling profile.

You need enough pressure so that the tire doesn't deform a lot
(flatten-out) as it turns. That's a function of the weight of the car
(and all cars are different). Too much air results in too little
contact patch surface (and a hard ride, and too much center wear, but
probably great fuel economy).

Most passenger car tires know they're going to be carrying (3700 / 4 =
) 925 lbs, so you'd think that instead of the ridiculous "max
pressure" rating on a tire that there'd be *the correct freeking PSI
rating* for 1000 lbs load.

What ever happened between Ford and Firestone's SUV tires? Was it
proven that Ford's door-jamb rating was not correct for the particular
tires that were blowing out on the highway?

On Mon, 26 Jul 2004 20:49:52 +0000, NG wrote:

> I have a pair of Neons, an '03 and an '04, and the tire pressure was getting
> low in the '03. I've never checked it since we've had it, but it was reading
> about 27 psi at each wheel. The door sticker reads 32 psi but the tire
> sidewall reads a max of 44 psi. So I'm wondering what should the pressure be
> set at? In years past, I always went about 4-6 psi less than the max listed
> on the tire to account for temperature changes, altitude, etc. So I ended up
> going with 38 psi all around. The ride is much firmer and I'm wondering if
> it's meant to be at 32 psi after all.

Of course it's meant to be at 32. Why do you think they put that sticker
on the door?

Did you ever think to check the owner's manual for information?

--
If you're not on the edge, you're taking up too much space.
Linux Registered User #327951

On Mon, 26 Jul 2004 20:49:52 +0000, NG wrote:

> I have a pair of Neons, an '03 and an '04, and the tire pressure was getting
> low in the '03. I've never checked it since we've had it, but it was reading
> about 27 psi at each wheel. The door sticker reads 32 psi but the tire
> sidewall reads a max of 44 psi. So I'm wondering what should the pressure be
> set at? In years past, I always went about 4-6 psi less than the max listed
> on the tire to account for temperature changes, altitude, etc. So I ended up
> going with 38 psi all around. The ride is much firmer and I'm wondering if
> it's meant to be at 32 psi after all.

Of course it's meant to be at 32. Why do you think they put that sticker
on the door?

Did you ever think to check the owner's manual for information?

--
If you're not on the edge, you're taking up too much space.
Linux Registered User #327951

Having been in the tire business for over thirty years and have seen
everything from the firestone 500 problem of the sixties to the present
problems. The air pressure issue is very important. You should check your
pressure based on the car makers recommendations. The pressure should be
checked once a month after the car has set for over 8 hours.
The proper way to do this as follows.
check the recommended air pressure from the door jam, for this example lets
use 32 psi.
Measure the air pressure with a reliable gauge.
Write down the pressure for each wheel position. i.e.; L/F 26 psi, R/F 29
psi etc.
Then if you do not have your own compressor drive to the nearest service
station that does and measure the pressure.
IE the L/F now reads 29 psi and increase of 3 psi
Inflate that tire to 35 psi ( 32 plus the 3 psi from the difference of being
cold.)
Then the following morning re-check

The problem with Ford and Firestone was 2 fold. Ford had recommended a low
air pressure of 25 psi which would have been no problem if the average
consumer checked his air pressure regularly. (not)
The failure mainly occurred in high temperature areas where tires heat up
faster.Also the fact that other tires had failed on the ford products leads
one to believe that it was a design flaw on Ford's part. If you look at the
location of the rear exhaust in relation to the rear tire it appears to be
very close thereby adding extra heat .


"MoPar Man" > wrote in message
...
> Circuit Breaker wrote:
>
> > > I have a pair of Neons
> > > I ended up going with 38 psi all around.
> > > I'm wondering if it's meant to be at 32 psi after all.
>
> > my view has always been that automotive manufacturers are paid
> > to engineer these things ...
>
> If you're a tire, you don't really care what car you're on. You care
> if you're mounted on the correct-sized rim, and then you care about
> how many pounds you're being asked to carry.
>
> It's actually a pretty dumb thing for car makers to put the tire PSI
> on the door jamb. Ok, well, they do know what tires they put on the
> car from the factory, so that's really the only *correct* situation
> where the door-jamb PSI spec is valid. Other than that, once you
> start putting on different tires (and different sizes) then the tire
> makers should have specs as to what a given tire should be pressurized
> to for a given weight to obtain the correct rolling profile.
>
> You need enough pressure so that the tire doesn't deform a lot
> (flatten-out) as it turns. That's a function of the weight of the car
> (and all cars are different). Too much air results in too little
> contact patch surface (and a hard ride, and too much center wear, but
> probably great fuel economy).
>
> Most passenger car tires know they're going to be carrying (3700 / 4 =
> ) 925 lbs, so you'd think that instead of the ridiculous "max
> pressure" rating on a tire that there'd be *the correct freeking PSI
> rating* for 1000 lbs load.
>
> What ever happened between Ford and Firestone's SUV tires? Was it
> proven that Ford's door-jamb rating was not correct for the particular
> tires that were blowing out on the highway?

Having been in the tire business for over thirty years and have seen
everything from the firestone 500 problem of the sixties to the present
problems. The air pressure issue is very important. You should check your
pressure based on the car makers recommendations. The pressure should be
checked once a month after the car has set for over 8 hours.
The proper way to do this as follows.
check the recommended air pressure from the door jam, for this example lets
use 32 psi.
Measure the air pressure with a reliable gauge.
Write down the pressure for each wheel position. i.e.; L/F 26 psi, R/F 29
psi etc.
Then if you do not have your own compressor drive to the nearest service
station that does and measure the pressure.
IE the L/F now reads 29 psi and increase of 3 psi
Inflate that tire to 35 psi ( 32 plus the 3 psi from the difference of being
cold.)
Then the following morning re-check

The problem with Ford and Firestone was 2 fold. Ford had recommended a low
air pressure of 25 psi which would have been no problem if the average
consumer checked his air pressure regularly. (not)
The failure mainly occurred in high temperature areas where tires heat up
faster.Also the fact that other tires had failed on the ford products leads
one to believe that it was a design flaw on Ford's part. If you look at the
location of the rear exhaust in relation to the rear tire it appears to be
very close thereby adding extra heat .


"MoPar Man" > wrote in message
...
> Circuit Breaker wrote:
>
> > > I have a pair of Neons
> > > I ended up going with 38 psi all around.
> > > I'm wondering if it's meant to be at 32 psi after all.
>
> > my view has always been that automotive manufacturers are paid
> > to engineer these things ...
>
> If you're a tire, you don't really care what car you're on. You care
> if you're mounted on the correct-sized rim, and then you care about
> how many pounds you're being asked to carry.
>
> It's actually a pretty dumb thing for car makers to put the tire PSI
> on the door jamb. Ok, well, they do know what tires they put on the
> car from the factory, so that's really the only *correct* situation
> where the door-jamb PSI spec is valid. Other than that, once you
> start putting on different tires (and different sizes) then the tire
> makers should have specs as to what a given tire should be pressurized
> to for a given weight to obtain the correct rolling profile.
>
> You need enough pressure so that the tire doesn't deform a lot
> (flatten-out) as it turns. That's a function of the weight of the car
> (and all cars are different). Too much air results in too little
> contact patch surface (and a hard ride, and too much center wear, but
> probably great fuel economy).
>
> Most passenger car tires know they're going to be carrying (3700 / 4 =
> ) 925 lbs, so you'd think that instead of the ridiculous "max
> pressure" rating on a tire that there'd be *the correct freeking PSI
> rating* for 1000 lbs load.
>
> What ever happened between Ford and Firestone's SUV tires? Was it
> proven that Ford's door-jamb rating was not correct for the particular
> tires that were blowing out on the highway?

I couldn't believe my eyes when I saw Harold Seldin wrote:

> Having been in the tire business for over thirty years and have seen
> everything from the firestone 500 problem of the sixties to the present
> problems. The air pressure issue is very important. You should check your
> pressure based on the car makers recommendations. The pressure should be
> checked once a month after the car has set for over 8 hours.
> The proper way to do this as follows.
> check the recommended air pressure from the door jam, for this example lets
> use 32 psi.
> Measure the air pressure with a reliable gauge.
> Write down the pressure for each wheel position. i.e.; L/F 26 psi, R/F 29
> psi etc.
> Then if you do not have your own compressor drive to the nearest service
> station that does and measure the pressure.
> IE the L/F now reads 29 psi and increase of 3 psi
> Inflate that tire to 35 psi ( 32 plus the 3 psi from the difference of being
> cold.)
> Then the following morning re-check
>
> The problem with Ford and Firestone was 2 fold. Ford had recommended a low
> air pressure of 25 psi which would have been no problem if the average
> consumer checked his air pressure regularly. (not)
> The failure mainly occurred in high temperature areas where tires heat up
> faster.Also the fact that other tires had failed on the ford products leads
> one to believe that it was a design flaw on Ford's part. If you look at the
> location of the rear exhaust in relation to the rear tire it appears to be
> very close thereby adding extra heat .

25 PSI?!?! That tire is rated for something like 40-44 PSI! It would seem
to me that this would result in *serious* overheating, even at Ford's
recommended tire pressure!

FWIW, I generally go by the tire's sidewall, and go to the max. Usually I
have a decent ride and decent gas mileage.

>
>
> "MoPar Man" > wrote in message
> ...
>> Circuit Breaker wrote:
>>
>> > > I have a pair of Neons
>> > > I ended up going with 38 psi all around.
>> > > I'm wondering if it's meant to be at 32 psi after all.
>>
>> > my view has always been that automotive manufacturers are paid
>> > to engineer these things ...
>>
>> If you're a tire, you don't really care what car you're on. You care
>> if you're mounted on the correct-sized rim, and then you care about
>> how many pounds you're being asked to carry.
>>
>> It's actually a pretty dumb thing for car makers to put the tire PSI
>> on the door jamb. Ok, well, they do know what tires they put on the
>> car from the factory, so that's really the only *correct* situation
>> where the door-jamb PSI spec is valid. Other than that, once you
>> start putting on different tires (and different sizes) then the tire
>> makers should have specs as to what a given tire should be pressurized
>> to for a given weight to obtain the correct rolling profile.
>>
>> You need enough pressure so that the tire doesn't deform a lot
>> (flatten-out) as it turns. That's a function of the weight of the car
>> (and all cars are different). Too much air results in too little
>> contact patch surface (and a hard ride, and too much center wear, but
>> probably great fuel economy).
>>
>> Most passenger car tires know they're going to be carrying (3700 / 4 =
>> ) 925 lbs, so you'd think that instead of the ridiculous "max
>> pressure" rating on a tire that there'd be *the correct freeking PSI
>> rating* for 1000 lbs load.
>>
>> What ever happened between Ford and Firestone's SUV tires? Was it
>> proven that Ford's door-jamb rating was not correct for the particular
>> tires that were blowing out on the highway?