MT0911

Hey guys, just have a quick question. I just recently purchased a set of new tires for the Vette and I was wondering what you guys can say/advise regarding the tire pressure. I have not mounted them yet so the purpose of this thread is more so I am aware once they are mounted.

I have a 99 FRC and at the moment I have C5 Z06 Motorsport Wheels (17x9.5 and 18x10.5). This is the tire setup I purchased:

Front: Nitto NT555 275-40-17
Rear: Nitto NT555RII 305-35-18

I'm thinking along the line of 30psi in the front and 28psi in the rear but to be honest I'm not sure which is why I am kindly asking all of CF. Any input would be great. Thanks guys!

RonJ

Most people will tell you run 30/30

Like you, I run a 2 psi difference front to back but I run 32/30. I've found it helps tire life.

RonJ ...

MT0911

Thanks. That's pretty much what I was thinking. I know 30/30 is the recommended psi for stock sized tires and since I'll be running a little wider I figured it would naturally change the recommendation by a little. I'll probably just end up experimenting. I appreciate the response!

rws.1

I run 30 psi cold all around spring and fall
drop it to 28 psi cold in the summer.

Vetteman Jack

I just run what the factory says - 30 psi cold in all four tires.

Quick Draw

jrose7004

30 psi all the way around.

BRTC5

+1 Seem to remember a thread on here from ET or Bill Curlee that got pretty heated. The final consensus was 30psi cold all round.

MagRed04C5

You should consider Nitrogen instead of air.
With nitrogen tire inflation, improvements can be noted in a vehicle's handling, fuel efficiency and tire life through better tire pressure retention (less fluctuation), improved fuel economy and cooler running tire temperatures.

MT0911

This is pretty much exactly what I was thinking hence why I am considering 30psi front and 28psi rear.

Thanks for all the input guys!

Jacks02

I aso run 30:30 F/R.

FYI: Yesterday, I checked to ensure 30:30, did almost 300 miles, periodically checked pressures on DIC while driving, and found presssure climbed to @32psi averaging 62mph in rain.

ALLEGRO

I would just do the 30/30 thing and see what you get. Wear will be an issue if you go too high or too low.

Good luck

flynbyu2

Our local vette speciality shop recommends 32 all the way around for best tire life.

MT0911

Interesting responses from everyone. I guess I'll just be experimenting and see what setup will prove to be the best. I'll probably just start at 30/30 and adjust from there as I watch how the tires wear over time. Thanks all!

Yello95

ET was one of the developing engineers of the C5 Corvette so I would stick with what he said and that would be 30-31 lbs HOT...so whatever that takes would be correct for me. In the summer I put 27 in all four and that gives me 30-31 hot. Just a little bit different in cooler weather...but always so it will get to 30-31 HOT. I have been using this pressure since I bought my Vette new in 2004 with great results...and yes there has been heated discusson for years on this same topic...go figure

Yello95

Did you realize that "air" is 78% Nitrogen to begin with?

DeeGee

As you know the book says 30 psi cold all round which is set by the manufacturer for the car not the tires.

The discussion that got heated was over what pressure that actually gives you. My experience of running Michelin AS ZPs was that the tires wore more in the center of the tread than at the edges. As we all know that's a sign of over inflation.

I ran 28 psi all round with the Michelins. The fronts wore well but even with those pressures the centers on the rears had a lower tread depth when I changed them recently. For me that suggests I could probably have used even lower on the rears.

As Yello95 says, the logic was that if you set a cold pressure of 30 psi in winter it gives about 33/34 psi hot. If you set the same pressure in Summer, with the higher temperatures, it gives 34/35 hot. I also found that in Vegas my hot temperature was higher than it is in UK where temperatures are lower. The suggestion from E-T was rather than set a cold temperature, set whatever you need to get your desired hot reading. IIRC E-T suggested 32 hot but I could be wrong. I do remember he suggested 28 cold.

I just fitted Toyo Proxes but they are non run flats so will be a different compound and totally different, softer, sidewalls. I have no idea whether the wear characteristics will be the same but the logic seems sound to me so I'll probably under inflate them slightly.

Bottom line is does it matter? Probably not a lot because I have no fuel useage figures to compare nor does the handling seem any different between 28 and 30 cold.

BTW I also tried Nitrogen one time and honestly couldn't see any difference.

99 vett babycar

I( also monitor my tire wear and check my tire pressure once a week.
I run 30psi HOT year round.

CBackous

^^^ lol

ChromeC5

Another thing to try is after being on the highway at a constant speed for a while, pull over in a safe spot and if you have access to a temperature sensor, measure the temperatures of the outside, middle and inside of the tread immediately to find out where it is hottest. If the center is hotter than the outsides, it could be over inflated a bit, if the center is cooler, it could use more air. I have not tried this, but it should work in theory. Emphasis on theory.