Tuesday, February 7, 2012

Checking Tire Inflation Pressure

Under Inflation: If your tires are under inflated by only 6 psi (pounds per square inch), it could cause tire failure.  Also, the tire's tread life could be reduced by as much as 25%.  Lower inflation pressure will let the tire to bend or squish more as it rolls.  This will create heat inside the tire, increase rolling resistance, and cause a reduction in fuel economy by up to 5%.  We know everyone is worried about mileage these days.  You will also see a reduction of steering precision and cornering stability.  6 psi doesn't seem that low, but remember, it normally represents about 20% of the recommended pressure.

Over Inflation: If your tires are over inflated by 6 psi, they could be damaged more easily when you run over potholes or debris in the road.  Higher inflated tires can't isolate road irregularities well, which causes them to ride harder and harsher.  However, higher inflated tires usually improves steering response and stability up to a certain point.  This is why people who use street tires in track events and road races inflate their tires more than normal.  The pressure must be checked with a quality air gauge because the pressure cannot be accurately estimated through visual inspection.

Time and Temperature: Their Effects on your Tires:  Tire inflation pressures change due to time and temperature.  Tires lose about 1 psi per month due to air escaping through the rubber as it stretches.  If you were to check your tires only every six months, it would not be uncommon to find them under inflated by as much as 6 psi.  Tire inflation pressures also fluctuate with changes in the outside air temperature.  This occurs at a rate of about 1 psi for every 10 degrees Fahrenheit (plus or minus).  So the tires you set correctly with an 80 degree ambient temperature will be under inflated by 6 psi at 20 degrees.

I've been riding in cars for 19 years, driving them for 2, and I never gave much thought to or realized how important tire pressure is. I see people all the time kicking their tires, feeling them, and just looking at them but they aren't actually checking the pressure or adjusting it.  Now I know a couple of pounds, up or down, can make a huge difference in the attitude of the car.  Not just the damage to the tires, but to the way the car handles.  This is a very simple, yet effective, way to keep your tires healthy.

Thank you for reading.  Please provide feedback to my email address: jacktheintern@gmail.com.  We want to make this a weekly thing so we value your opinion.



  1. Oh Jack you wonderful little man! I will follow this like a red spotted tortoise. (Red spotted tortoises have been known to follow their owners around where ever they go.) Very informative stuff.

  2. This is really informative. I'll keep visiting for more of your posts.