Tire pressure....always wondered

Well if i dont ask the 'obvious or dumb questions', no one does.;) Why do all tires come with a 'Max. pressure' on the sidewall, and it is always like 42-44 PSI, and yet every car will say to keep the pressure at a much lower number, no matter the brand/make of tire? I think my 2006 Aveo is 30 PSI all around, yet the new tires I am getting tomorrow, the 5th set!!!, at 35K miles, says 44 PSI Max. pressure. I know if you ride them with higher pressure you get slightly better mileage, but the tires wear out faster. The lower pressure gives you a softer/comfortable ride, but uses more fuel. The way my Aveo eats tires, it doesn't seem to matter what pressure I have in them, but I keep them at 30-32.

So....why do the makers of tires say a HIGH pressure, and yet the car maker tells you a much lower pressure? I have always wondered this, and decided to ask...might as well. I cant be the only one that wonders this. I prefer the hard ride with higher pressure, but the road noise get to be to much, and the tires wear out even faster!!!

The softer pressure does give a nice soft ride, but to me it seems the sides of the tires wear out FAST at the low pressure. Am I wrong? Even with rotating/balancing, they wear out on the edges when the pressure is the low 30 Chevy says to keep them at. Any one got some answers to this stupid question?:-?

Max pressure is just that, the maximum pressure the tire was designed for. You would only ever fill the tire to the max pressure if you were loading that tire to it's maximum designed load. If you were to try and max out the tire load in an Aveo, I think your suspension would have a few words for you first...

Remember, as you increase the pressure in the tire, less of the tire is in contact with the ground. This reduces braking effectiveness, reduces your drag, and increases MPG. The reverse is true as you lower tire pressure.

The manufacturer is going to recommend a tire pressure that provides effective braking, adequate tire life, and acceptable fuel economy. Of course, those numbers assume you stay with the suggested tire sizes. Change the tire size out of spec and you are on your own to figure that out

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Originally Posted by EAD15

Max pressure is just that, the maximum pressure the tire was designed for. You would only ever fill the tire to the max pressure if you were loading that tire to it's maximum designed load. If you were to try and max out the tire load in an Aveo, I think your suspension would have a few words for you first...

Remember, as you increase the pressure in the tire, less of the tire is in contact with the ground. This reduces braking effectiveness, reduces your drag, and increases MPG. The reverse is true as you lower tire pressure.

The manufacturer is going to recommend a tire pressure that provides effective braking, adequate tire life, and acceptable fuel economy. Of course, those numbers assume you stay with the suggested tire sizes. Change the tire size out of spec and you are on your own to figure that out

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I appreciate the reply. This is kind of what i said in my post and knew already. Except that Max. pressure is used for 'loading up the car'. Like I said, lower pressure that is on the car, on every car, is for comfort and soft ride. The high pressure will give you more mileage, not much, but some, and a harder ride, and wear out faster. I just never understood why there is such a big difference in the numbers to inflate them to.

You'd think the tire makers would make tires with a much lower Max. pressure, closer to what all car makers put on the car, and make the damn tires last longer, ride quieter,grip better, at the lower pressure, since 95% of people will keep it at the lower pressure, and the tire wears out faster at that lower pressure, even with constant balancing/rotation.. BUT then again, tire makers want/need us to buy more and more tires from them, and they want them to wear out ASAP, its all 'planned obsolesence' I guess..

The max pressure is used for mounting the tire on the rim and well as when you are driving on it. If you Go past the max pressure before the tire seats on the rim, the tire sidewalls could blow over the lip of the rim.. Also while driving, the pressure changes when the tire heats up from use, friction with the road. If you have a 44 psi max pressure tire running at 44 psi, Spinning at highway speeds it can raise the pressure with temp over 50 psi depending on factors. If you hit a pot hole or something with the tire at max or over it will likely pop or lose the tread surface (ever see retread tractor trailer tire remnants? road gators).

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Originally Posted by petrified.rabbit

The max pressure is used for mounting the tire on the rim and well as when you are driving on it. If you Go past the max pressure before the tire seats on the rim, the tire sidewalls could blow over the lip of the rim.. Also while driving, the pressure changes when the tire heats up from use, friction with the road. If you have a 44 psi max pressure tire running at 44 psi, Spinning at highway speeds it can raise the pressure with temp over 50 psi depending on factors. If you hit a pot hole or something with the tire at max or over it will likely pop or lose the tread surface (ever see retread tractor trailer tire remnants? road gators).

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Well I don't plan on going anywhere near the 'Max pressure' on my tires. I just wondered what it meant and why it is so much higher than what the car says to inflate the tires to,no matter the tire make or the car make. I have always wondered this since I started driving.
I still prefer a harder tire to give a more 'German' type of ride. Like in a Mercedes ....but at the rate my Aveo eats tires, I keep them at the low recommened pressure, and rotate them and balance them constantly.

On advice from a suspension specialist, I use 38 front and 36 rear, I drive mostly alone, with full fuel and no luggage.
See My Garage for details.

Get alignment done yearly. If your tires are wearing unevenly. ...

Extreme over pressure will cause the tire to wear more in the center of the tread . Extreme under inflation will cause the tire to wear more at the outside edges of the tread .

As has been said , lower air pressure gives softer ride .

Regardless of what has been said , higher air pressure ( if not taken to the extreme ) will give longer tread life . There is less flexing of the tire , less heat , less rolling resistance .

I try to run my tires at max pressure . If your Aveo is eating tires . It is most likely not air pressure , unless they were run extremely under inflated . More likely out of alignment , damaged parts , worn out parts and / or poor design .

Excessive wear front , back or both . Center , one edge , both edges ?

Ask around and try to find a " Better " Alignment shop .

How are the struts ? Various bushings ?

God bless
Wyr

Wyr nailed the specifics of wearing patterns, and petrified.rabbit hit the max pressure issue - especially important for those of use logging highway miles in the desert in the summer - so I won't retread those comments (heh, see what I did there!).

I try to run about 34 consistently. I'm not noticing excessive tire wear, and I went about three+ years on the tires that came on the car when I bought it in 2012. In fact, that reminds me, it's probably time for a rotation.

I'd like to hear more specifics or send us photos when the new set gets bad. Hope this set goes much better for you.

zs

Brand matters, too. I bought my 2008 Aveo5 (5-speed manual) in 2009 with 28k miles. Dealer said the Riken Raptor tires were factory original. I got over 80k miles out of them. I replaced them with Kumho Solus KR21 tires, and drove those for 70k miles. I am now on my second set of Kuhmo Solus KR21 tires. I have consistently kept the pressure at 30-32psi, and had them rotated every 8k-10k miles. The alignment has been adjusted twice in last seven years. I live in MN where potholes abound during our two driving seasons (winter and construction).