You may not have noticed that the tire was going flat. The first inclination you have is that there is a thumping noise, corresponding with a jerking of the steering wheel, as you drive. You don’t want to keep driving on that flat tire. 

If there’s any chance of saving the tire, continuing to drive on the flat tire, while not a safe idea in terms of maintaining control of the vehicle, will surely destroy the tire. In fact, if you drive on a flat tire far enough, you’ll lose the tire and begin to damage the rim. Replacing a tire that was, otherwise, in good condition is bad enough. Replacing one of your wheels gives the cost of the event an unpleasant boost.

There are also occasions when tires go flat suddenly. This is called a blowout. Depending on your speed at the time of a blowout, there is a serious question of whether you’ll be able to maintain control of the vehicle. This is a particular concern if the blow out is to one of the front tires where you steer the vehicle. 

If you have a TPMS (Tire Pressure Monitoring System) warning light, you may be alerted to the problem by a symbol in your dashboard. Otherwise, you’ll want to monitor the tire pressure of your tires. You need to look at them and observe if they’re going flat. Periodically, and if you think a tire is looking flat, you need to take a tire gauge and check.

Why do tires go flat?

Obviously, tires go flat because they’re losing air. The air escapes from the tire because there is a leak. The valve stem, where the tire is pressurized, can leak. It can leak at the valve that spins into the stem or it can leak around where the stem is designed to seat into the rim. 

Tires also go flat around the rim – where the rim and the tire meet. Once a tire is ‘seated’ in the rim, it usually won’t leak here – ‘usually.’ As winter approaches, however, the cold can cause a tire to lose its grip on the rim; you can have a rim leak.

The other way that a tire goes flat is if it is punctured or cut. A nail or another sharp object in the road can punch through the rubber causing a leak. But objects in the road can also cut a tire. A cut is generally beyond repair. A puncture wound can often be repaired. However, if the puncture is in the sidewall of the tire, this is probably not the case.

Even if a tire doesn’t go flat, if it has a leak, it will affect the wear of the tire. A tire that is low on air will show greater wear on the outer shoulders of the tire. If a tire has too much air pressure, which can create a greater danger of a blowout, it will generally wear more down the center. In both cases, the wear is generally greater while you have less control of the vehicle – less of the tire is making contact with the road.