BlackHawk T/A

iTrader: (3)

There is a lot of talk about tire pressure in this forum, however most people forget to mention how they are getting their measurements. Were the pressures taken after driving on a 90 degree day, or after the car had been sitting for 24 hours in a garage?

What made me post this was my own personal findings. It's gotten pretty hot here now, 80-90 day to day. I hadn't set my pressure since I put these bad boys on in March. It was probably 50 degrees and the car hadn't moved at all. I set them at 35 front, 25 rear. I was able to do this because they were overfilled when they were mounted. The tires in question here are listed in my sig.

When I checked them yesterday after driving, I was shocked to find the fronts at 40-45psi and the rears at 35psi! That is much higher than 3 months ago. So, I let the fronts down to 35 and the rears to 25 which is where they should be for best traction and even wear. I'll have to check them before work some day (car is garaged) to see what the difference will be when cool.

So the question is, how and when are you checking your pressure? And when people recommend 25psi for the drag radials were they hot or cold? My thinking is it could be part of the problem for people with traction problems or uneven wear.

Also to add: I did notice the car was noticeably less responsive after I did this. Quick steering at speed was a little more "mushy" than it used to be, which I don't necessarily like.

Sorry for the long post. Maybe I should just fill them with nitrogen and be done with it.

KillerKlown

I can tell ya that on my car (ws6) i keep the tire press 30 cold or 34 hot all around (275/40 17's). They tend to raise 5-7 deg when fully hot. 1 thing I've noticed, if the tires are inflated too high (ft or rr) it will dart/wander more on crappy roads. Hope that helped a bit.

BackinBlack02SS

iTrader: (7)

On stock tires, I agree with this. One way to help the pressure fluctuation is to use nitrogen instead of regular air.

NHRAMAN

iTrader: (1)

I try to keep mine around 32psi cold..all around....275/40/17 ....

BlackHawk T/A

iTrader: (3)

Bump...

Xsta Z 28

iTrader: (2)

Always check and fill your tires cold. Hot air pressure can increase 4 lbs or more . . .

For example, a tire inflated to 30 psi cold (recommended for F-Cars) and you drive around getting the tires hot, the air pressure can increase to 34 to 35 psi.

Rescue Ranger

iTrader: (10)

I wouldnt've reduced your psi after driving it hot. Put the pressure where you want it to be when the tires are cold.

BlackHawk T/A

iTrader: (3)

It would make sense to me that you would want to set them when warm, because that is the pressure you are going to have when you are driving the car. Why would you care about the air in your tires when it sits in the garage?

lrk322

iTrader: (11)

WHen GM reccommends 30 psi they are telling you that is what you want to set it to when they are cold. They know that the psi will go higher when they get hot so thats why they tell you to set them cold. If they told people to set them after driving when theyre hot they wouldnt know what temperature the tires were and people might be setting them too high or too low because fo the variation in temperature. By setting them when they are cold there is less room for error and it just makes more sense.

Xsta Z 28

iTrader: (2)

Because cold pressure is more "consistant" vrs hot . . .

And that is the way it has ALWAYS been recommended.

BlackHawk T/A

iTrader: (3)

That's about what mine are set at. But my 555R's are at 25psi cold.

The car sure seemed more responsive with 5psi more in the front though...

black00TA

iTrader: (3)

your going to want to run 30psi in all your street tires.

running different pressure than what the inside of your drivers door calls for changes your whole suspension geometry. unless your an engineer and have calculated the effects for every +/- 3 psi your tires receives on each corner. then dont expect to get real world positive handling characteristics without sacrificing at LEAST that much on another aspect.

as handling will only be effected negatively by these changes.

6LITEREATER

iTrader: (56)

I have stock Z06 rims with 275/40 ZR17's in front (which I will now set to 30psi cold) and 295/35 ZR18's in the back... Do I also set the backs to 30 cold?

Thanks!

Viper

iTrader: (6)

Yes, rears too

6LITEREATER

iTrader: (56)

So the different tire and rim (18") size doesn't make a difference in the pressure setting?