What Tire pressure should I use?

[bugaboo90]

I have gt2 with 18" tires. On the door plate, it says 36 front 39 back.

First, I always thought 32 was the normal, so these seem high to me, but I am coming from "Normal" cars, so I assume this is normal for high speed cars.

Second, the dealership pumped it at 44ish. I don't know why they did that.. Should I keep it at 44ish or back it down to the door plate.

the car drives fine and it is freaking cold here in ohio. Not as cold as up in our 51st state but.. still cold.

Thank you

 

[DaJackson]

Go with what the door plate says.

 

[bugaboo90]

Thx

Go with what the door plate says.

 

[DaJackson]

To expand on this for everyday driving go with the door plate.

If you need more grip you can lower the pressure a few PSI but you will wear the tires at a higher rate and unevenly.

If you need less grip or less rolling resistance increase the PSI but you will wear the tires at a higher rate and unevenly.

TLDR: Use the door plate pressures unless you have a very specific need for a short time.

 

[CDv6]

Look at this message I just posted in another tire-related thread...

Invest in a good tire pressure gauge​

 

[westcoastGT]

I have gt2 with 18" tires. On the door plate, it says 36 front 39 back.

First, I always thought 32 was the normal, so these seem high to me, but I am coming from "Normal" cars, so I assume this is normal for high speed cars.

Second, the dealership pumped it at 44ish. I don't know why they did that.. Should I keep it at 44ish or back it down to the door plate.

the car drives fine and it is freaking cold here in ohio. Not as cold as up in our 51st state but.. still cold.

Thank you

51st State ..........................hahaha ,you guys already tried that and it didnt work out so well for you , war of 1812 , we kicked your ass . Now behave ! Or we will send our PM down there ( please )

 

[CDv6]

Now behave ! Or we will send our PM down there ( please )

I'd say idle threat, except he's literally here right now.

 

[me&stinger]

Mine are...

Front: 31psi
Rear: 31psi

 

[Satansfist]

Doesn't it say on the tyres? I'd go with the tyre manufacturer, been a number of times on work vehicles where we change out the "standard" tyre and to use the vehicle recommendations (door panel) is plainly crazy.

 

[CVD]

You generally should not inflate to the pressure listed on the tire sidewall. That’s usually a max pressure under load. It’s safe but expect to get a terrible ride and treadwear doing that. As stated above the pressure on the door is the correct starting point unless you know what you’re trying to accomplish.

 

[Ozstung]

It's written on a placard on the door sill 36F & 38R that's for 19" wheels.

 

[nhcowboy28]

It's written on a placard on the door sill 36F & 38R that's for 19" wheels.

It’s different for every tire/wheel combo offered. So yes, everyone needs to look at the placard. Then look at the manual of you want to go back and forth between 18/19s. It lists the pressures for the regional market.

 

[itguy61]

Doesn't it say on the tyres? I'd go with the tyre manufacturer, been a number of times on work vehicles where we change out the "standard" tyre and to use the vehicle recommendations (door panel) is plainly crazy.

Absolutely not! That is the maximum pressure for that particular tire. Most tires are used on different vehicles with different characteristics. Always go with the door plate.

 

[Ed B]

44 PSI seems way high. It's likely you'll be in for a surprise when we (Ohio) get warmer temps for a few days. I prefer to adjust tire pressure to my driving requirements via temperatures. With the wet weather further south this past weekend, for my GT2 AWD I found about 38 PSI was good for 18" Firestone Performance All Weather tires, gave fairly good temps at tire's middle (average of inner and outer), but I do have some variation (6 degrees total from inner to outer that might indicate alignment issues (I did take it on the Mid Ohio track in October, so it's possible I "moved" something). This is my first trip on the all seasons, so take it with a grain of salt, but I'd bet 38 would be better for you than 44 psi (I'd only run 42 PSI MAYBE for autocross, but haven't done with this car). FYI, I have found I get better tire life since I've adopted this method of measurement -- to be fair, it's possibly due to changes in tire manufacturing as much "evening out" tire temps, no scientific comparison attempted.

 

[itguy61]

I don't get deviating significantly from the placard with stock tires. I understand tuning but significant changes can cause uneven tire wear and ride/handling issues.

 

[me&stinger]

My current tire pressures are...

Front
---------
37 37
Rear
---------
39 39

 

[Ed B]

Me: (note: rr camber is definitely off -- there's 15 degrees (F) difference across tire face, rf probably off -- spreadsheet 'suggests' that I add 7.5 degrees of center temp, haven't had a good opportunity to take it in for correction. Highest avg. temp is left front, but the left is higher front and rear suggesting that a good modification would be for the driver to lose 50 lbs.)

Front
----------
37 39
Rear
----------
39 36

 

[eflyguy]

Doesn't it say on the tyres? I'd go with the tyre manufacturer, been a number of times on work vehicles where we change out the "standard" tyre and to use the vehicle recommendations (door panel) is plainly crazy.

You are misinformed. The only number on the tires is max safe pressure.

The correct pressure for your vehicle with OEM tires has been determined by vehicle manufacturer testing, and will be far lower than the max rating of the tire. It will also vary for different vehicles, even for the same tire. Finally, even the manufacturer recommendation is an average for average use. The pressure can be raised for freeway driving, and lowered for performance driving.

 

[OriginalRobby]

I once saw 42 / 42 (front) and 40 / 40 (rear) during hot summer days, nothing bad happened that I am aware of.

 

[narsnail]

I used what the door said for a while, found it a tad soft. 41 front and 38 rear is now what I use.