Aleckor

My tires say that the absolute max for the tires is 44 PSI, so I was wondering what a good amount of air would be for that. The dealer told me I need at least 28 pounds of pressure in there, but I think 28 is kind of low if 44 is the absolute max. In the end, I ended up going with around 39-41 PSI for each tire.

What PSI do you all use and on what max do your tires say? I'm trying to determine if I'm overinflating my tires or not. Thanks.
-Aleckor

2fastforyouraSS

32 is perfect

g5mike

35psi is just perfect

SSKevinSC

32 psi

cheesetits

I use 32 for the street, 25 for the track.

R&C_rallySS

I use 33 psi for every day, and 20s for racing up front.

My06Kobalt

32 in the front, 34 in the back. runnin on 215/40/17's

OrngBalt

dude.... 32... thats just about what every manual and every shop teacher will ever teach you. just the max is 44 doesn't mean you want to be anywhere near that

Aleckor

So 40 is overinflated then? or is it still alright at 40? That's what I'm trying to determine. Some of you are saying 32, some of you say 35, which is it?
-Aleckor

justin04

if you have 44 psi of air in the tire the center of the tire will wear quicker? is that true?

Aleckor

If you have an overinflated tire it will - I'm not sure 44 PSI will constitute as overinflated unless your max suggested PSI for your tire is below 44. But then again, being at exactly 44 PSI when your max is 44 is probably not a good idea either. So I would say that you are correct to assume the center of your tire will wear quicker as a result of overinflation if your PSI is 44 and your tire's max is 44. (It just doesn't make logical sense to be at the very max - You wouldn't blow up a balloon so much that even a tiny tiny bit more air would pop it would you?)

As for whether or not 44 PSI is overinflated is something I'm wondering myself. I have 40 PSI in my 44 PSI tires, and I'm curious if my tires are overinflated or not. Most of the guys here are saying that 32-35 PSI is optimum for 44 PSI tires (or any tires I guess?)
-Aleckor

SlifoxS

there's a sticker on the inside of the door frame that says "cold tire pressure: 35psi"

32-35 would be a good range to aim for

Adirondack_Cobalt

is there really hard and fast (no pun intended) rule about expansion with temperature. What I mean, cold inflation is 32psi, but when that tire is driven, does it really vary what the pressure increases to?

Scott

g5mike

don,t forget in hotter tempatures your tire pressure expands more,I usually drop it 2psi in the hotter months and yes over inflation will cause the center of the tire to wear more quickly

OrngBalt

Your car rolls off the lot at 32-33, every time you get it checked, they reset it to 32-33, when you bring it to any mechanics shop for anything... they reset it to 32-33. If you get new tires they.....



well you get the idea. 40 is WAY overinflated

g5mike

wonder why it says 35 on the inside of the door then?

InfinityzeN

I suggest you study up on this site http://www.carbibles.com/

Specifically this section http://www.carbibles.com/tyre_bible.html

With a 44psi max, I would recommend ~39psi. Take a MPG rating and also see how it handles there. Your MPG should go up, handling increase, slight rise in ride stiffness, and any weird tire wear should go away.

32psi is from 1990's tech tires. Car companies have not changed their recommendations since then, although tires have advanced significantly. Try google, should help you out.

FuriouS

X 1 Million.

32-35lbs.. MAX

an0malous

mine says 32, both in manual, and inside of door.
could possibly be your particular tire/rim setup in the pontiac?


Either way, that "max pressure" rating, is telling you the following:

Hey buddy, inflate me to this psi, and give the tire a good kick, and it may just blow your leg off.


just stick to around 30-35.

InfinityzeN

Actually the max psi is cold. Tires are designed to handle 6 to 10psi over that, which is what will happen if you drive for a long time or drive really really hard.

Aleckor

How long does it usually take for tires to lose their pressure? In other words, am I safe to just leave it around 40 PSI with a 44 PSI max? because inevitably eventually it'll drop back down to the 35-39 range which seems to be okay with most of you, though a lot of you think 32 is better.

Am I correct to assume it'll be okay or should I be letting the air out of my tires right now?
-Aleckor

an0malous

I would man.
40 is pretty extreme.

light'bolt

Too much air, the middle area will wear faster
Too little air, the outside edges wear faster.

Side of the door is OEM perfered setting.

Aleckor

http://www.sportcompactcarweb.com/te...ressure_guide/

I found a pretty good formula to use but I don't know how much the Cobalt weighs. How much does a Cobalt LS 2.2L weigh? Is it in my manual somewhere?

Anyway the formula is:

Vehicle Weight in lb/100) + 2 psi at heavier end + 2 psi all around if suspension and alignment are stock.

Example: Stock 911, 3,000 lb.
(3000/100) = 30 psi
Add 2 psi all around = 32 psi
Add 2 psi to heavy end = 34 psi at rear
With modified suspension, the result is 30 psi front, 32 psi rear.

Area47

32 front
34 rear.