Tires
Thread Starter
Instructor
Joined: Aug 2016
Posts: 103
Likes: 6
From: Tyngsboro MA
Tires
My 2009 has Goodyear runflats on it.....the original stocks. Odd thing is they say on them max psi is 44 and when I bought it 2 months ago I never checked the air so today I checked and there is 25 in all of them so I moved them to 40. I started the car and brought it out to drive and the overpressure warning for all 4 tires is up on the dash. Why say 44 but the computer says no to 40?
Racer
Joined: Jul 2011
Posts: 336
Likes: 115
The PSI on the sidewall is the MAXIMUM that should ever be put into the tire. It should never be considered the normal operating pressure.
This is the only place the manual talks about 38 PSI :
How fast are you gonna be driving it?
The manual also tells you how to find the recommended pressure:
This is the only place the manual talks about 38 PSI :
If you will be driving your vehicle at speeds of
175 mph (282 km/h) or higher, where it is legal, set
the cold inflation pressure to the maximum inflation
pressure shown on the tire sidewall, or
38 psi (265 kPa), whichever is lower.
Example:
You will find the maximum load and inflation
pressure molded on the tire’s sidewall, in small
letters, near the rim flange. It will read something
like this: Maximum load 690 kg (1521 lbs)
300 kPa (44 psi) Max. Press.
For this example, you would set the inflation
pressure for high-speed driving at
38 psi (265 kPa).
175 mph (282 km/h) or higher, where it is legal, set
the cold inflation pressure to the maximum inflation
pressure shown on the tire sidewall, or
38 psi (265 kPa), whichever is lower.
Example:
You will find the maximum load and inflation
pressure molded on the tire’s sidewall, in small
letters, near the rim flange. It will read something
like this: Maximum load 690 kg (1521 lbs)
300 kPa (44 psi) Max. Press.
For this example, you would set the inflation
pressure for high-speed driving at
38 psi (265 kPa).
The manual also tells you how to find the recommended pressure:
A vehicle specific Tire and Loading Information
label is attached to the center pillar (B-pillar)
of your vehicle. With the driver’s door open, you
will find the label attached below the door
latch. This label shows the number of occupant
seating positions (A), and the maximum vehicle
capacity weight (B) in kilograms and pounds.
The Tire and Loading Information label also shows
the size of the original equipment tires (C) and
the recommended cold tire inflation pressures (D).
label is attached to the center pillar (B-pillar)
of your vehicle. With the driver’s door open, you
will find the label attached below the door
latch. This label shows the number of occupant
seating positions (A), and the maximum vehicle
capacity weight (B) in kilograms and pounds.
The Tire and Loading Information label also shows
the size of the original equipment tires (C) and
the recommended cold tire inflation pressures (D).
Last edited by ProCycle; Nov 4, 2016 at 07:30 PM.
Thread Starter
Instructor
Joined: Aug 2016
Posts: 103
Likes: 6
From: Tyngsboro MA
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
All tires have a very high maximum number on the sidewall. This number is the maximum pressure that is ever to be applied to the tire, which applies to the mounting of the tire onto the wheel. To get the bead of the tire to seat to the wheel, the installer must apply extra air...the sidewall is telling him to not go beyond 44 psi to get the bead to seat. This number has nothing to do with the pressure recommended for normal driving. That pressure is always on a label on the drivers door jam on all cars, not just the Vette. If you are storing the car and want to bump up the pressure, that's fine but you must expect the overpressure warning because the car doesn't know why you are doing it, just that the pressure is too high for driving. The car warns low at 24 psi and high at 42 psi. 30 psi cold in the morning is what GM says on the label.
Last edited by cclive; Nov 5, 2016 at 08:19 AM.
