CLEVELAND, Ohio – When the temperature drops, so does the tire pressure in your tires, which is why they can look perfectly fine one day and low on air the next.
Many people have no doubt witnessed this phenomenon in recent days as the particular thermometer reading plunged into the 20s.
A drop of 10 degrees Fahrenheit can lead to a decrease inside tire pressure of one pound per square inch (PSI), said Bill Yu, an engineering professor at Case Western Reserve University.
Will Hilliard, wheel manager at Conrad’s Tire Express & Total Car Care in Cleveland Heights, estimates that an 8- to-10 degree drop can result in a decline of 1-to-2 PSI.
What’s happening is the colder temperature slows down air molecules inside the car tire, making them less energetic, Yu said, and reducing the frequency in which they hit the particular tire.
As a result, a tire can appear as though it has lost air even when it hasn’t, Yu said. Once the temperature warms up, the pressure inside a tire should go back up. Yu said typically the low-pressure warning appears on the dashboard when the particular tire stress drops below about 25% of the rated pressure.
But there could be something else at work.
When the air inside the tire contracts, plus there’s much less pressure pushing the tire against the particular metal rim, it can result in a gap inside the seal that allows air to escape, Hilliard said.
When it’s warmer and the air is expanding, the particular increased pressure makes the close off tighter, he said.
Hilliard said based on his experience, air flow pressure usually does not return to where it had been after the heat goes back up.
“No tire, no rim is perfect, ” he stated.
He recommends filling the tire to the recommended PSI because more comfortable temperatures alone probably won’t bring this back to the particular pressure it was originally.
Keeping wheel pressures from rated levels improves gas mileage and may avoid uneven wear if low pressure is left for a long time,