360Rocket

I'm sure most will answer "the manufacturers recommended tire pressure" but is anyone running more air pressure? or less air pressure? and what is your reasoning behind it? better handling/cornering? better traction performance? better tire wear? better fuel economy? etc.

I have been running at 30 PSI as recommended but the outer and inner edges of the tires are wearing faster than the middle of the tire and I dont get as much "road feel" at 30 PSI as I get at 35 PSI or even 40 PSI.

1bdvet

I run what the door tells me, with no issues.

JCtx

You don't need any more than 30 on the hard runflats man. I tried 32, but the ride was substantially harsher, and there were reports of excessive wear on the middle of the tires, so no sense in running more than 30. My tires are wearing quite evenly, but cornering is going to increase outer wear, while slabbing inner wear (due to aggressive negative camber on the GSs). I seem to be matching both at the ideal rate for now.

Finally, it's impossible that you're wearing the middle of your tires due to 'excessive' air pressure of 30 psi. But you'd suerly do that with the pressures you're suggesting. Plus the car would ride like on bricks. I suggest you stick with stock pressures. Good luck.

0Anthony @ LGMotorsports

Stock size tires and wheels? It would be odd that you have wear like that given everything else on the car is stock.

I could see a tire that is a different size than stock, on a stock wheel causing some odd wear issues. If you are wearing on both the outer and inner edges though that would signal an under inflated tire.

Is it doing this front and rear both?

HOXXOH

Around town I run 32 cold in the winter and 30 cold in the summer. On road trips (2500 mile minimum) I'm also at 30 cold. These are non-RF's and I use the universally available 78% Nitrogen mixture. There is currently 114K miles on the car and only 34K was with RF's. I prefer a little more pressure locally, since most trips are in the 2 to 15 mile range and heating to 34 in the winter takes a while, but in the summer the roads are already hot, so the 30 gets to 34 pretty quick. Road trips are in warm weather and because of the distance it gets up to 34 too.

I've never had an alignment and tires have worn evenly until replaced. I drive a little more aggressively than the average Vette owner.

Gearhead Jim

Me too, seems to work well and I like the price.

Gearhead Jim

On our 2006 Z51, I used 30 psi cold, front and rear, until we sold it at 44k miles.

On our current 2009 Z51, I also used 30 psi until last summer (60k miles). Then I made a minor change to 31 psi front and 29 psi rear, cold. I didn't think I would even notice it, but the steering seems more lively and the handling is closer to neutral. I was surprised and pleased that such a small change felt so much better. BTW, we are using the Michelin PS2 ZP runflats now, not sure how those pressures would work with different tires or the other (F55 or base) suspensions.

jpee

I must be the "oddball" I don't use run flats any longer.. I use my MT Drag radials year around and use them both to & from the track..

With that being said, I run 34 in all 4 tires.. in this cold weather they will go up to 36 -37 on longer trips..

I still run 34 during the HOT summer months, and they will go up to 38 - 40 if I'm "cooking along at 80 + mph..

I never go into corners fast so thats not an issue.. My Rear tires (MT Drag Radials) wear out a lot sooner then the fronts, at the track I lower my rears to 18 lb of air... I leave the fronts alone and they will come down to 36 while I'm sitting in the pits between rounds..

and no I don't put the fronts up to 40 like some racers do... Less work to just leave them at 34 and forget about it...

I have the Z51 and I "STILL" don't feel the ride is to harsh even when the tire pressure goes up to 38 on long high speed trips... & the FRONT tires wear perfect.. I just have the front end aligned every yr in April after the winter pot holes that I accidentally hit...

I get the rears aligned also but they wear out about mid season (I use 2 sets of MT Drag tires a season)

I would rather have my tire pressure 2 lb HI than 2 lb LOW.. maybe thats me, but I never want to see my tire pressure lower than 32..

And in the COLD weather (10 - 15 deg) my tires will go down to 30 if I leave the car outdoors for a long period of time...

Vette_DD

My 08 coupe wore the tires a little more on both the left and right sides, so I ran 32 in them and that fixed that problem.

jadatis

Its a bit more complicated. I can calculate the lowest save pressure for your situation. Then if you stay above that you can play with the pressure above that for riding quality .
As you describe the inner and outer side of each tire is worn off more then the centre , wich would indicate to low pressure , but is it not only the inner or outer side of the car of each tire, look again.
Then its a matter of alignment like toe in or out thats the cource.

If its the pressure I need next.
From tire maximum load or loadindex, kind of tire to determine the pressure needed for the maximum load/maxloadpressure/reference-pressure ( Pr) , wich is not the maximum pressure of tire.
Because of tire I asume this is american forum, so P-tires Pr 35psi/2.4bar, and XL/reinforced/Extraload Pr of 41psi/2.8bar.
European tyres its a bit different.
Then the exact sises of tire and speedcode ( letter between S and Y).

Then from car GAWR and GVWR ( gross axle/vehicle weight rating).
Empty weight and way you load it normally to estimate the axle loads for your normal use.
Camber angle ( alighnment wheels like this on axle /-\ ( moast rear done)).
motor front or rear .
Maximum technical speed of car or speed you sertainly wont go over in your use.

Greatings from Holland
Peter

0Anthony @ LGMotorsports

Unless your going to check humidity levels in the tires weekly....that is probably the best thing you can use.

peter pan

I try to keep between 29-31 on ours and seems to have great tire wear.

360Rocket

Just normal Firestone run flat street tires and OEM wheels Anthony. It's hard to hit 30 PSI as I find lately that we have morning temps of high 50's and by the afternoon we have temps in the mid 80's so I can see tire pressure vary in just one day from 26 PSI to 34 PSI. I figure we average 75? so maybe I set it at 30 cold at 75 degrees.

This is my first experience with Run flats, I used to run my Cobra tires (BFGoodrich KDW's)when I wasn't using drag radials in the back at 40 PSI on an 18 inch rim and have good performance and wear results.

Thanks for the input gang and greetings from the USA Peter.

johnodrake

Ditto

0Anthony @ LGMotorsports

Of course pressure is going to vary with temps...you might have to start them out at 30-32 cold like they said above. Generally a starting pressure of 30 psi at 65-70 degree's F should be a good starting point.

Gearhead Jim

Tire pressure will change by about 1 psi for every 10'F change in temperature. So if the day warms up by 30', you will gain about 3 psi.

Since underinflation is usually worse than overinflation, I set my pressures cold in the morning as recommended, and expect to see an increase of 3-6 psi as I drive and as the day heats up. The car and tire makers understand that situation, and base their recommendations on an increase while driving.

Since my garage is warmer than outside during the winter, I use the 10' = 1 psi formula to set my pressures properly for the real outside temp.

I learned that lesson when I picked up our new 2001 at the museum in December, they had set the tires to 30 psi at the 71' room temperatrue inside. Next morning on the way home, I started the engine and immediately got four '"Low Pressure" warnings. Ooops.

HOXXOH

That's kinda hard to do in the summer in Phoenix when the overnight low is still in the 90's.

When you pull out of the garage in the morning and all the fluid temps never cooled below 100 from the day before, you really don't get too concerned with anything else except putting the AC on max cool.

0Anthony @ LGMotorsports

Texas isn't that different in the summer