Everyone knows that driving on bald tires is unsafe. Even on dry, well-maintained roads it’s an accident waiting to happen. Driving fast or on wet, slippery roads only increases the chances of an accident. The dangers of driving on worn out tires isn’t just folklore – it’s a proven fact. The National Center for Statistics and Analysis at the National Highway Traffic Safety Administration conducted a study that found 26.2% of auto crashes involved vehicles with insufficient tread (1/16th of an inch or less).
Protecting yourself and your loved ones starts with understanding the role tire treads play in safe driving, and when it’s time to change your tires.
What Do Tire Treads Do?
Treads provide the traction necessary to grip the road in potentially dangerous weather conditions, such as rain, snow, ice or mud. If we only drove on dry roads, treads wouldn’t be necessary because smooth tires are best for gripping dry surfaces. That’s the reason NASCAR and other racing cars use tires without treads when driving at high speeds – because it’s safer. But most of us drive in all kinds of weather conditions, and we need good treads to drive safely. Without them, the cars we drive would be almost impossible to control on wet, icy or slick roads.
Tire treads consist of carefully designed grooves, or channels, on the surface of the tire. They keep us safe by forcing water away from the tire on wet roads. This enables the tire to maintain a solid grip on the road even when the rain or snow is coming down hard. Treads also play an important role in making sure the car travels in the direction that we steer.
Are Bald Tires Dangerous?
You bet! In fact, bald tires are one of the leading causes of accidents, especially those that involve a single vehicle. What makes them so dangerous?
- Too much heat buildup. Driving creates friction between your tires and the road surface, and friction creates heat. Too much heat can cause a blowout, causing you to lose control of the car, especially at high speeds. Tires are made of materials that can withstand fairly high levels of heat. But once it reaches a certain limit, the tires become unsafe. The faster you drive, the more heat the tire must be able to withstand. That’s why having proper tread depth is so important – treads help cool the tire by allowing air to flow in between the grooves. Bald tires don’t have the grooves provided by treads, so the heat can easily build up to unsafe levels.
- Increased risk of hydroplaning. Another side effect of bald tires, hydroplaning occurs when a layer of water gets between the tire and the surface of the road. When this occurs, the tire loses its ability to grip the road, causing the car to spin out of control. If you’ve ever hydroplaned while driving a car, you know that it can be very difficult to regain control. Modern tire tread patterns contain deep grooves that channel water away from the tire, which enables it to maintain a firm grip on the road in wet conditions. As the tread wears away over time, the grooves become shallower, making them less effective at directing water away from the tire. The shallower the grooves, the greater the risk of hydroplaning, even on roads that are only slightly wet. When tires are completely bald, hydroplaning in heavy rain conditions becomes highly likely.
- Difficult handling in snow or ice. Wet roads aren’t the only safety problem with bald tires. Unless you have good snow tires, which have wider and deeper grooves than everyday tires, driving on a road covered with snow or ice can be a risky proposition. Many winter tires also come “sipes” – small, thin grooves or channels cut into the edges of the treads. These help improve traction and handling by providing more surface area to grip the road. If your snow tires don’t have sipes, take them to your tire shop so they can add the extra edges for you. Keep in mind that as your tread wears away, so do the sipes. Having both in good condition will minimize the dangers of spinning out on icy roads.
- Loss of air pressure. Bald tires are bad news all around. Not only do they make it harder to control the car in most conditions, they also lose air faster than tires with good tread depth. Even if you make a point to check your tire pressure on a regular basis, low-tread and bald tires can lose their air sooner than you think. Once your worn out tires become under-inflated, they become even more dangerous to drive. Under-inflated tires can’t grip the road properly, even in dry conditions, which can make it harder to steer your car. They can also affect braking by causing the car to skid during sudden stops. They even put a dent in your bank account by reducing gas mileage, which drives up your gasoline costs. Under-inflation also causes the remaining tread to wear out quicker, which means you have to replace your tires sooner than expected.
- Sudden blowouts. This is possibly the biggest threat from driving on bald tires. In addition to improving handling in bad weather, treads also help reduce the chances of suffering a blowout while driving. Experiencing a blowout is dangerous at any speed; blowouts at high speeds can be fatal. Treads can’t prevent all punctures, but if you run over a nail or other hard, sharp object, they stand a better chance of resisting the blowout than bald tires. Few moments behind the wheel are more terrifying or dangerous than a sudden blowout at freeway speeds.
What Counts As A Worn Out Tire?
Tires don’t have to be completely bald to be considered a worn out tire. Once the treads are worn down to a certain level, they become unsafe to drive. It’s easy to tell when your tire treads are wearing low. However, you need to inspect them on a regular basis, which can be easily done in just a few minutes. Tire professionals recommend checking them at least once a month. Here’s what you should look for:
- Not enough tread depth.When evaluating the amount of tread on your tires, “eyeballing” it isn’t good enough. For a proper evaluation, always use a tire tread gauge. They don’t cost much, can be bought at most service stations or auto parts stores and are easily stored in your glove compartment. They’re also simple to use, even if you don’t have any auto experience. Another technique involves inserting a penny into the tread with the “heads” side facing you. If you can see all of Lincoln’s head, your tread is too low and it’s time to get new tires.
- Visible indicator bars.To make it quicker and easier to judge the amount of wear on your tread, today’s tires are made with tread indicator bars. These flat rubber bars are built right into the tire, but you can’t see them when the tires are new and have plenty of tread. As the tread wears down over time, the bars gradually become visible. When you can clearly see them, it means the tire tread has reached unsafe levels.
- Sidewall cracks. Bald tires aren’t the only danger sign to look for; cracks in the sidewall also pose a potential Tire sidewalls don’t wear away like tread, but they tend to dry out as the miles go by. This can lead to cracks or cuts that compromise the structural integrity of the tire. Very small cracks are common on older tires, and don’t pose much of a threat. Large cracks should not be ignored. Any time you spot one, head to your tire shop as soon as possible for a professional evaluation.
Worn out tires can also can develop bulges and blisters that create weak spots on their surfaces. These can increase the chances of a sudden blowout, and can also lead to skidding, hydroplaning or losing control of your car by reducing the tire’s ability to grip the road. As with large cracks, bulges and blisters should never be ignored.
Be Tire-Safe: Rotate and Replace
Tire professionals recommend rotating your tires on a regular basis for two important reasons: it extends the life of the tire and keeps you safer by having the tread wear evenly on all four tires. When you purchase new tires, you receive the manufacturer’s recommendations for how often to rotate the tires. If you lose the paperwork, simply call the tire dealership and ask. As a general rule of thumb, plan to rotate your tires every six months or 7,500 miles. Your driving habits and local weather conditions may dictate more frequent rotation.
- Sooner or later, your tires will need replacing. For safety’s sake, sooner is always better than later. Never replace your tires based solely on the estimated lifetime mileage because many factors can determine how long a tire lasts. Instead, learn how to measure tread depth, check for signs of tire damage on a monthly basis, and don’t delay when the tread depth falls below 1/16th of an inch. Driving on worn out tires puts you and everyone else on the road at risk, so be a good citizen and keep your tires in good condition at all times.