Tire Pressure - How much?

[VaGT]

First of all, I have the front end noise caused by the tires. My dealer can't read tsb's right and only wanted to clean them and remount, but he wouldn't touch it until I changed the brakes to rule them out. Anyway, making a long story short, at 29K on the car, I think I am just going to run these till winter and replace them on my own... get a better tire, avoid the fight, get all 4, and stop wasting my vacation time at the Pontiac Dealer. (Needed since wife is 7 months pregnant :D).


On to the meat of the question...

I inflated the tires yesterday as they were a little low, and forgot my tire pressure guage. I ended up putting in 40psi :eek:. I drove it yesterday, and noticed that the tire noise was gone. Thoughts on this?

I woke up and checked the psi this morning, and noticed it was high and I backed it down to 35psi. I notice the door says 30psi, but me thinks that is too low for the front tires. I got a 4 wheel alignment from Monroe last year, and the guy there put them at 35 and told me to keep it there. Which is best? I am waiting to hear from my wife (she has the car now) if 35 gets rid of the noise too. Advice? Winter vs Summer? How much is too much?

Also... my rear tires are at 28 and 26psi. I need to bump them up.

[Jagey]

I would just stick to the factory recommendation. They obviously picked that number because it was thoroughly tested and it was the optimium amount to produce even tire wear. But in any case, you can put slightly less than the factory recommendation in the winter to get better traction. Othewise, stick to the factory recommendation if you want your tires to wear evenly.

[pdltodamtl]

You can go as high as is listed on the face of each particular tire, but as was previously stated, GM engineers have printed the optimal pressures on your door sticker.

[Dr_Kyle]

http://www.grandamgt.com/forum/showthread.php?s=&threadid=4829&highlight=tire+pressure

[Joey K]

I run Mine at 30 in the rear & 34 in the front. In the winter I go up 5lbs, seems to let the tire break through the snow covered streets a little more & cuts down on the "snow shoeing" effect. I came up those figures after alot of trial & error. At 30 up front they seemd to wear on the outside faster then the center, that's why I deviated from what was recomended.

[VaGT]

Joey K

I noticed the same thing... the edges of the tire wearing pretty fast. Even with the door saying 30, the Monroe guy said 35.

[Joey K]

Ya, I was getting a thumping outta my front end, had the tires balanced twice before I figured the center was "flopping" because there was not enough pressure & it allowed it (the center of the tire) to flop under fast rotation, usually between 62 to 75 mph. The sagging center was also the cause of my outside tire wear. It (tire pressure) might all depend on your driveing habbits, I know I regularly go over 75 mph on alot of the interstate travel I do. Sometimes I set the cruise as high as 90mhp. But usually keep it anywhere between 70 & 80. & like I said that's w/in part of the range I was getting the tire flop.

[Panacea]

30-32 psi is the recommended pressure! However, if you're getting the noise from the tires, putting more air can possibly eliminate it. Sounds like what happened to you. But, do you really want to drive at that high of PSI? You'd be wearing out the center of your tires pretty quickly.

[Joey K]

34 sounds high to you? I only run the extra 5 in the snow, when there's no contact w/ the pavement. Besides, id I wear em out faster, it'll be a good thing! lol

[Greed4Speed]

I run 32 psi front to make up for the engine weight and 30 psi rear. I imagine the pressure printed on the car door is for the RSA's. I'm sure different tires would have different optimum pressures.

Even running the pressures I stated on the stock RSA's, and regular rotations, they still wore uneven. I'm glad they're gone!

[VaGT]

Originally posted by Greed4Speed
I run 32 psi front to make up for the engine weight and 30 psi rear. I imagine the pressure printed on the car door is for the RSA's. I'm sure different tires would have different optimum pressures.

Even running the pressures I stated on the stock RSA's, and regular rotations, they still wore uneven. I'm glad they're gone!


At this point (30K), I don't have any worries about tire wear with these. If 35 PSI will get rid of that noise at this point, then 35 it is.

With winter coming up, and my frequent winter trips to Pa, I generally err on the side of caution with winter coming up. I'll probably have around 38K miles by the time winter comes, and if the summer is hot, that means more wear. So, I'll be looking at new tires this winter anyway.

Not to mention that at 30PSI, I too was seeing the uneven wear on the edge. I have had the front aligned twice and the rear once. (One front was paid for under warrantee).

GM says to change oil every 6-8K miles too :D , and they also like going with the absolute lowest bidder on rotors... quality be damned... then charge $200 each to the fools willing to have them changed by GM out of warrantee.

[Joey K]

Well put VaGT.

[karni24]

The TSB you are talking about I assume is the one in which the Goodyear RSA's are wearing grooves into the lip of the rim, and the tires rubbing in the grooves are causing the noise. The TSB does state that increasing the tire pressure to 44psi is on way of diagnosing the problem. This really isn't the permanent fix though. I am a service consultant at a Pontiac dealer and have run into this problem quite a bit, usually from 20,000 miles on up. The other thing you (or the dealer) should do is to mount a set of rims/tires onto the suspect vehicle from a known good vehicle to check if the noise goes away. My Grand Am's tires and rims have been on approx. 5 different cars already! It really is the tires. Problem is, there's not a whole lot you can do about it. I have yet to see a set of tires warranted because of this problem. GM says it isn't safety related, so they won't cover them. I had a couple people call Goodyear, but I never found out what they made out. The people who did decide to purchase new tires for there car to eliminate the noise have confirmed that the noise was gone once they mounted the new tires.

[BMOBYLE]

Originally posted by karni24
The TSB you are talking about I assume is the one in which the Goodyear RSA's are wearing grooves into the lip of the rim, and the tires rubbing in the grooves are causing the noise. The TSB does state that increasing the tire pressure to 44psi is on way of diagnosing the problem. This really isn't the permanent fix though. I am a service consultant at a Pontiac dealer and have run into this problem quite a bit, usually from 20,000 miles on up. The other thing you (or the dealer) should do is to mount a set of rims/tires onto the suspect vehicle from a known good vehicle to check if the noise goes away. My Grand Am's tires and rims have been on approx. 5 different cars already! It really is the tires. Problem is, there's not a whole lot you can do about it. I have yet to see a set of tires warranted because of this problem. GM says it isn't safety related, so they won't cover them. I had a couple people call Goodyear, but I never found out what they made out. The people who did decide to purchase new tires for there car to eliminate the noise have confirmed that the noise was gone once they mounted the new tires.

Your dealer doesn't cover these???

[VaGT]

karni24


You really should re-read that TSB. It clearly calls for replacing the tires with 2 new front tires (without the grooves).

No offense, but sometimes the reason people get bad service is because the people in the service department think they know what is contained in a TSB, but they don't check for updates etc. It is my understanding that when the problem first came out, the solution was not a tire replacement, but now it is.

The service manager I spoke with actually brought up this TSB, but was simply going to clean and re-mount the old tires.

[AaronGTR]

I keep mine at 35psi in the summer and 30 in the winter. The only real reason GM recommends 30psi is to decrease road noise and for ride comfort. 35psi will give you better fuel economy and better handling (especially at high speeds). In the winter if you're driving on packed snow, ice, or wet roads it's better to have less pressure. It makes the tread flatten out slightly which gives a wider foot print for more traction.

[Joey K]

it's the other way round in the winter. You're just Makeing it more difficult for the tire to bite through the snow & reach the pavement. In the winter, the wider the tire the less traction you'll have. Why do you think snow shoes are so wide? - To enlarge your footprint so you'll stay on top of the snow.

[AaronGTR]

If I was driving around in deep snow all the time you'd be right.:rolleyes: But since I'm not driving a truck I stay on the road, where it's either packed snow or ice, or just wet because they've salted and everything melted. In these conditions (which is 90% of my winter driving) a flat wide contact patch is better.