This is a two part special on the topic of Flat Tires

A flat tire is something nobody wants because a flat tire will leave you stranded alongside the road. When a tire loses all its air, it loses its ability to support the weight of the vehicle. Unless the tire is a special kind of tire called a run-flat, the sidewalls are not strong enough to support the weight of the car unless there is a certain amount of air pressure inside the tire. So, a puncture that allows the tire to lose air will cause the tire to collapse and go flat.

Any tire, new or old, can go flat if it is punctured. New tires that have thicker treads are more resistant to punctures than worn tires with thinner treads. But the deeper treads on a new tire can also channel sharp objects into the tire actually increasing the risk of a puncture if you drive over a nail or other sharp object.

If a tire goes flat while driving, you will hear and feel a thump, thump, thump vibration, or sound. A flat front tire will usually cause a hard pull towards the side that has gone flat.

If a tire has gone flat while the vehicle is parked, hopefully, you’ll notice it before you try to drive away. If you don’t, you will definitely immediately feel the vibration, and your vehicle will have the tendency to pull to one side.


Driving on a flat tire will quickly ruin your tire. Without any air support inside the tire, the sidewalls of the tire will be pinched between the road and the edges of the wheel rim. Driving even a short distance (say more than 1/2 mile) may be enough to cut or destroy the tire. And if the tire comes off the rim, which a flat tire can do, you may end up damaging your wheel, too.

Causes of Flat Tires

Common causes of flat tires include:

Leaky valve stems.

There may be cracks in the rubber stem, a poor seal between the valve stem and wheel (due to corrosion or wheel damage), or an internal air leak in the valve stem because the valve is loose, faulty or jammed with dirt. Making sure the valve stem is covered with a cap will keep dirt out and help keep air in. This type of leak can be repaired by replacing the valve stem, or the valve assembly inside the valve stem.

Caused by driving over sharp objects.

Road debris includes junk like nails, screws, steel wire from exploded truck tires, broken glass, sharp rocks, etc. Try to avoid running over debris in the road if you see it and can react in time (which is hard to do when driving in heavy bumper-to-bumper traffic). This type of flat can be repaired by patching or plugging the tire, or replacing it if the tire is too badly damaged to be repaired.

Bead leaks between the tire and wheel.

This is often due to rust or corrosion on the wheel, but can also be caused by a bent rim (hitting a curb or pothole). Air leaks here can also be caused by a damaged bead sealing surface on the tire, possibly the result of mishandling when the tire was originally mounted on the rim (not using a bead lubricant, attempting to force the bead over the rim, using the wrong mounting hardware). This type of leak may require dismounting the tire and cleaning the rim and the bead surface of the tire. If the rim is bent or damaged, the wheel should be replaced. If the bead surface on the tire is damaged, the tire will have to be replaced.

Wheel air leaks.

Aluminum alloy wheels can be porous and slowly seep air over time. Adding a sealer to the tire will often cure this type of leak. Or, the tire can be dismounted from the wheel so the inside of the rim can be painted or coated with sealer.


No repairs are needed for this other than to reinflate the tire with air (use a pump, portable tank or aerosol can of tire inflator/sealer). Be careful where you park your vehicle next time!

Click here to read Part Two

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