Use that air gauge: Why checking tire inflation pressure is so important.

You could have the best tires in the world on your vehicle, but it wouldn't matter if the air pressure inside them was less than perfect. Tire load capacity, durability, traction and handling go hand-in-hand with air pressure, so pull out that air gauge. Too little or too much pressure can negatively affect performance.

Most people assume that the tire itself determines air pressure, and while this holds some truth, most air pressure is determined by the vehicle itself. Yes, the vehicle—tires can fit a variety of different vehicles, but the vehicle manufacturer knows exactly what type of tire pressure will draw out the greatest performance. The psi branded on a tire's sidewall indicates the tire's maximum cold inflation pressure, but that maximum pressure might not be what your individual vehicle needs for maximum performance. So, when using your air gauge, you should always check your vehicle manufacturer's air pressure recommendation found in your owner's manual. (Read more.)

See all air gauges available at Tire Rack.


Friday, December 30, 2011 by William Root

Several years ago Tire Rack had a publication sent to me that said something different. It indicated that inflation should be what was on the sidewall. I took that to heart and have run that ever since. When I bought a new Mustang in 2004 my gas mileage was terrible. I check air pressure and increased it to the the sidewall pressure. It increased by 7mpg. I don't think that the manufacturers should determine the pressure because they use whatever brand is bid. They also use the same pressure for high performance tires and all season on the same vehicle. I could continue but in my opinion you are tire experts and should retest and reconsider your opinion.
Friday, December 30, 2011 by Tire Rack Team

Tire Rack does not recommend that the maximum tire inflation pressure published in the tire specification or branded on the tire’s sidewall be used in place of the vehicle manufacturers’ recommendations, in part because there are so many variables.

Depending on which 2004 Mustang model you have, our records indicate Ford recommends 30psi, 32psi or 35psi.

Depending on which tire you are using, the maximum cold inflation pressure could be 35psi, 44psi, 50psi or 51psi.

While higher inflation pressures will reduce tire rolling resistance, they will also reduce ride quality and the tire’s ability to absorb impact with potholes, driveways, curbs and debris on the road. This could possibly lead to road hazard damage or tire failure.

An increase of 7mpg simply due to using higher cold inflation pressures is beyond what the laboratory results indicate is possible, so we’ve got to believe you fine-tuned your driving style as well. Running the maximum cold inflation pressure branded on the tire sidewall is within the tire manufacturers’ specifications, however it is not a substitution for the vehicle’s recommendation.
Tuesday, April 23, 2013 by Don Johnson

I had a conversation with a fellow I had met. Talking about tire pressure. He said that the maximum pressure displayed on the sidewall of the tire was for a standard temperture of 80F. Is this so ? He also said that the tire pressure needed to be adjusted up or down 1 lb. for every 10 deg. above or below this temp. Please advise !
Friday, April 26, 2013 by Tire Rack Team

Sorry to say but your friend is not quite right. Just like the vehicle manufacturer's recommended pressures found on the door jamb placard, the maximum inflation pressure listed on the sidewall is considered a "cold" pressure measured at ambient temperature. Knowing that temperatures are not constant through the day these cold inflation pressures are intended to be taken at the cool part of the morning before the heat of the day and driving add additional inflation pressure due to the temperature gains. These gains are built into the equation, and should not be altered trying to anticipate or factor out the changes from temperature.

On the amount of pressure change with temperature you and your friend are correct, that pressure changes by about 1 psi for every 10 degrees of temperature change.

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