OK, so I have the Z06 Wheels from an '02 on my '93. As far as correct tire pressure, would I find out what a stock Z06 ran, or what?

Is it more dependent on the wheel construction and wheel/tire size, or the weight of the vehicle?

Am I making sense, or blathering like an idiot?


Thanks!

30-35psi if youre using air, 36-38psi if youre using nitrogen.

Tire pressure should be set based on the manufacturers recommendation, not the wheels or tires used. That pressure is posted on the label on the rear edge of the drivers door
Your 93 should be 35 PSI., that said, I run 30 in my 93 for improved ride based on personal driving style and the fact that GM lowered their recommendation in 94 while vehicle weight changed less than 30lbs.
If you regularly drive at high speeds, lower pressure is not recommended, it will raise tire temperature and increase wear.

So the fact that I went from, say a 275/40/17 to a 285/35/18 has no effect on the recommended tire pressure for that wheel/tire combo?

I would not have thought that.

Thanks!

No mate, not really. The pressures i gave are cold pressures, and i recomend nitrogen over air. It will be quite abit less sensitive to temperature, and the pressures will fluctuate alot less due to this.

It may have an effect on your speedo calibration though, TopTechx6 will be best equiped to answer that, having been down the road of speedo sensor gears quite a few times in the past few months, he is somewhat of an expert in the field.

Yeah, I looked at one of those charts that somebody posted a link to on another site that goes into detail about spedometer discrepencies when the height of a tire changes on a vehicle.

IIRC, the taller tire actually makes the car go slower than indicated on the speedo. And in my case, not by very much. My rear wheels are taller and wider, but the aspect ratio of the tire is lower. It doesn't completely even out, but it's no big deal. And my fronts are still 17" and have a lower profile, so I'm not sure if that brings it even closer to stock overall or not.

Basically, I'm not concerned with the speedo accuracy, really.


The highways in Colorado are 75mph. I set my cruise to 80 all the time in every vehicle I drive, and have driven by or even passed many state troopers with no issues at all.

And if I happen to accidentally run it up to 120, then I deserve whatever I get, even if the radar gun only reads 118.

Front tire or wheel size has nothing to do with it, cause the rear wheels are the drive wheels.

Quote:

Your total tire height difference is a grand total of .19" (3/16).
275-40-17 = total tire height of 25.66"
285-35-18 = total tire height of 25.85"
Grand total diff = .19" or .007%
:thumbleft:

What is that?.... MATH?

I don't do math...

Mike, what does it equate to in revolutions per mile?

Quote:

Hold on a minute, my calculator display doesn't have that many digits in the display.

7.4 revolutions per mile less with the 18" wheels/tires.



edit; goofed on the first number of 17.xx. I used tire/wheel height instead of circumference. DOH!

WOW, they're gonna last WAY longer!

Mike that 2 digit calculator you have there is too old mate.

The stock standard 17x9.5 with a 275/40/ZR17 812 revs per mile, with a 285/40/ZR17 on the same wheel, it will be 802 revs per mile.