His tires are driving him around the bend

Rob, I was parking my car in the underground and heard a hissing sound echoing off the walls. It sounded like I had a tire leak so I checked them all but found they had pressure, albeit a little low.

Thinking nothing of it, I drove out the next day only to hear the same sound again. I took my car to the shop but they could find nothing wrong with my tires either. I had them check out the underside of the car and still no signs of problems.

This is driving me nuts! Do you have any suggestions as to what the problem might be?

Yours in frustration, Tim

He wants to drop the top but has issues Dr. Cato prescribes the Greek goddess Eos to cure what ails him

Tim, at the risk of sounding like a smart-alec, there really is nothing wrong with your car. You are experiencing the natural phenomenon of tire squirm.

Tire squirm is a term used to describe the forces acting on the sidewall of a tire as the tread meets the ground. The weight of the car is supported by the tire sidewalls. As the sidewalls press down, they press the tread together, which affects the contact patch with the ground. As tires are made of rubber and held under inflation pressure by air, there is a lot of flex to the tire. This flex dissipates across the tread where it meets the ground. The sidewalls pressing down have almost the same effect as an underinflated tire.

Tim, as this squeezing takes place, the rubber makes a sound that simulates a "hiss," which is what you heard in the parkade. This is the same type of thing that happens when you rub a pencil eraser across a hard surface. The sound is actually the tire tread sliding or squishing itself together. This is tire squirm.

The higher the tire pressure, the less the tire squirm - low tire inflation will result in more tire squirm. This is the balance that tire and car manufacturers must achieve. They will not be able to completely rid tires of squirm, but they have come a long way since the development of radial tires because back in the day, bias ply tires were notorious for squirm - so much so that bias tires were dangerous.

So Tim, a little piece of mind - just remember to keep your tires inflated to the specs listed in your owner's manual.