Where the Rubber Meets the Road:
Use a Quality Pressure Gauge Early & Often
Under the blistering heat of summer, asphalt roads can reach a surface temperature of 150 to 180 degrees…and in Phoenix, AZ they’ve reached 200 degrees!
That’s important to know because heat increases your tire pressure. In the summer you’ll see significant changes in the tire pressure of a shaded or garaged vehicle versus the same vehicle after it’s been driven for hours. That’s why it’s important to check your tire pressure regularly with a quality pressure gauge. You can’t tell just by looking! Tires that “look OK” can be underinflated by as much as 5 or 6 psi and that can impact your safety, increase wear and reduce performance and fuel economy.
The tire pressure recommended in your vehicle’s owner’s manual is also found inside the driver’s door. This information provides the ideal ‘cold’ tire inflation pressure. That means you should check the pressure in the morning before you drive more than a few miles, and before rising temperatures or the sun's heat increases it.
The rule of thumb says that for every 10° Fahrenheit change in air temperature, your tire's inflation pressure will change by about 1 psi (up with higher temperatures and down with lower). During summer months if you set your car’s tire pressure in the mid-afternoon after you’ve been driving it, don’t be surprised if the “cold pressure” is 2 psi lower the following morning. It doesn’t mean you have a leak, it may simply be the temporary change that can occur daily. If your cold air pressure decreases by more than a marginal amount (2 psi), have your tires checked by a professional.