Do it when tires are cold. I go with the 30 psi cold setting and my tires wear very evenly and the ride is just right.

 

always measure pressure on a cold tire

 

 

Your tires should read 30-31 psi when hot...but do not add air when tires are hot...add air when cold so to get to the optimum temp hot set the pressure at 26-28 cold.......


If you set the pressure at 30 cold then on a hot day they can get up to 36-38 hot and that is too much...just my .02

btw...here is where I got my info and I have lived by it for the past 10 years and it works for me...
=======================================
heres where I got my 30/31 lb hot answer from over a decade ago...its a long explanation but worth reading and I still go by what he said...best tire pressure info I ever read...



Quote:


Originally Posted by Evil-Twin

"Ive posted this at least 200 times. That sticker on the Door is a DOT compliance sticker.. it's designed to keep people from inflating their tires to 63 psi as it says on the sidewall of the tire.. Tires are not made for specific cars, they are made for specific sizes, therefore, the weight bareing load is different based on the car and its weight. While many people read that as a cold tire pressure, summer or winter .. it is not accurate. 30 cold means nothing because the tire is not in work mode.. Therefore it's not at operating temperature. What you have to do is keep the tire in the sweet spot... 30 psi is the right tire pressure for a 3200 lb vehicle. However, inflating a tire to 30 when they are col dmeans nothing.. Its when they are actually rolling..... take for example, a cool morning test in you garage might yield a 30 psi tire pressdure.. but take that tire out on the road and by noon on a hot day 90+ and on a black top road, the surface temperure of that road can see 160 degree F. NOw that 30 psi tire is at 38 psi.. which will make the tire over pressured for a 3200 lb car. making the footprint ( contact patch ) become center high , reducing the contact patch, wearing the center out of thew tire and reducing the traction and performance and fuel economy..

IN the summer.. there is a big swing in ambient temperature, as much as 40 degrees in 24 hours..

So after giving you all of this information. it is fairly easy to see where your tire pressure should be. For me, in the summer I set my tires to 26/28 psi. this will insure that my tires do not get over pressured by mid day. You don't have to adjust the pressure daily or weekly or even monthly.. but between June and August, you want light pressure cold (26/28 psi ) this will put them in the sweet spot, and give you the best performance and insure against premature center wear. On a really hot day 90+ and you are out and about.. check with the DIC and see if your tires are where they should be.. if they are north of 34 or 35 psi, drop a few pound to get you to 30/31 psi. That should be your set point. check once a month, because 02 escapes through the side wall ( more in the summer ) . Winter time, tire pressure become lower because the air is more dense , so you may have to add tire pressure in the winter because with O2 loss and cold temps you don't want to be running around on 26 psi, you may even get a low tire warning in the winter, and need to pump up the pressure.. This is what I call tire tuning for best performance and tire longevity..

This is how all Indy, and Nascar events are monitored by pit crews. They monitor track condition and track temperature to insure proper tire pressure so they can get that extra two laps out of a tire, and those extra miles of fuel consumption. Races are won or lost on improper tire pressure. Proper tire pressure tuning is good for your cars performance and also for its fuel economy.. and of course your wallet.. understand tire pressure and it will greatly benefit your Corvette experience. BTW just 1 or 2 psi can make a big difference. That extra mile to the gallon of fuel, and those extra thousand miles to a set of tires.
POST #189 on this subject.
Happy summer
Bill aka ET

So Keep it in the sweet spot." ( 30/31 psi Hot )

 

had new front tires mounted today. make a run to the parts store a warning pops up on the dic . pressure to high . says pressure is 43 on one and higher on the other . I forgot to check pressures after having them mounted , have yet to figure out why they put so much pressure in them . I always run 30 to 32 in all my vehicles .

 

I dont agree with the long story given.
pressure advice is to give the tire when warm a deflection, that wont overheat the tire when driving the speed it is determined for.
the only way to measure it accurate is cold, so when inside tire temp = outside tire temp.
Pressure advice is given for cold temp of 18 degr C / 65 degr F.
So to do it perfect , you should calculate back the measured pressure to that temperature.
when colder, the pressure is lower so more deflection, so more heatproduction a cicle, but also cooling down of rubber is more because of higher temp differences. So for savety you dont need to highen up the pressure. For fuel saving and ridingquality you may do it.
when hotter the other way around but difference is that you may not let out air to adviced, because the tire needs that lesser deflection not to overheat them.

 

If you are getting new tires try to use a store that uses Nitrogen to fill the tires. Instead of seeing your tires gain 4-6 lbs from cold to hot you will only see a 1.5-3 lb gain. On short runs in the summer I found I barely gained a pound in a 20 minute drive.

 

So Keep it in the sweet spot." ( 30/31 psi Hot )[/QUOTE]


Then why does Corvette's Owner's Manual shows this? I keep mine at 30 cold and they generally go to 32 when hot and as summer comes will probably be higher due to the fact I took off the run flats and put new tires on. But, I do check the pressures via instrument panel fairly often just being curious.




I do believe I'll follow them than you. ;-)

 

I live in Fl. and keep the tires at 30 cold. They only rise 2 lbs. when hot. Maybe I'll come down 2 lbs. for a little softer ride, may shorten life of tires but so what, my comfort is more important.

 

 

Excellent for you...keep doing what GM says is correct...they are always right...we all know that...I cannot give an example where GM has ever given bad information anywhere or screwed up anywhere...they got it right with the balancer issue..with the column lock issue..with their run flats issues...and lots of other problems...so please keep following what works for you

When I do what you do (30 lbs cold) in the summertime with temps 90+...mine go up to 35-36 and that is way too much for me...GM's 30 cold door sticker is a generic sticker...so lets both keep on doing what is best for us....

 

 

hi Mitch, I have the same problem with my left rear sensor. Just wondering if you found a solution for the problem?
thanks, Dale

 

I inflate my tires at 30lbs. I know that heat makes tire pressure go up but didn't think it would be as much as mentioned above.
Next summer I will check my tires after a long drive in 90+ weather to see the tire pressure. If it only goes up to 32 or so I will not change a thing but if I see that the pressure is around 36-38 then I will definitely lower the pressure when tires are cold.

 

That is a wrong and dangerous way to work.
if tirepressure rises to much it means that temp in tire rises to much.
Then you should highen up the cold pressure to give the tire lesser deflection so lesser heatproduction.
then warm pressure is higher but lesser psi between cold and warm.

 

Last Summer down here in S Louisiana I never saw my old run flats go over 32 psi even on the hottest days. Of course I'm not abusing them, just cruising the back roads. I've also checked my motorcycle tires just for the heck of it returning home from a 100 or so mile ride in 90+ Temps and never saw them more than 2 or 3 lbs. up.
It will be interesting to see how the Hankook do this summer, but so far, never saw them over 32 either. But, Summer is not here yet.
And I agree , from years of racing motorcycles, too much pressure gain=hot tires, raise the pressure.

 

A good rule to go by is for every 10f of temperature increase, you get 1 more lb of tire pressure.

If you’re recording 37-38 when warm, you’re either doing something wrong when checking at cold temps or need to move

 

As with any rather subjective question, I am not surprised by the differing opinions, but the one rather glaring issue that nobody touched on was what tire we are talking about. In particular, whether we are talking about the stock run flats or a standard performance tire.

Second thing, most tire pressure gauges are crap. Kind of a pet peeve with me, as years ago in another life, I had to calibrate production manifold pressures for large heavy manufacturing machines, which required fractions of a PSI accuracy. Still have my trusty old Precision Pressure Manometer, with real accuracy of +/- 0.25%, which is approx 0.018 PSI. I will tell you that even most higher end tube type pressure meters are a couple of PSI off either way, and there is normally quite a variance from one to the another. Most higher cost dial models are around +/- 1 to 2 PSI, which is still alot.

What is interesting is, when you nail the cold tire PSI right to the 10th on a calibrated meter, you then realize the TPMS variance. I find at cold temp, 2 of my TPMS read one PSI off, one high and one low. However, when warm they generally read the same. The point is, don't use the TPMS readings, as I believe they are rated for approx 4% variance.

Lastly, when determining the correct PSI for each brand and type of tire for all around driving, the only real way to figure this out is doing the chalk test. Once you get the pattern completely flat across the tread when fully warm, then put the car in the garage and the next morning read the PSI. That will be pretty darned close to as optimal as you can get without tracking with a stop watch.

FWIW, I hope this helps.

 

Thank you, had never heard of that but makes good sense. LOL on gauge accurate readings I don't think 5 psi gauges I have all read the same. Some as much as 3 psi difference.