Driving on bald tires is not just unsafe, it’s an accident waiting to happen – especially if you like to drive fast or you frequently drive on wet, slippery roads. According to a study conducted by the National Center for Statistics and Analysis at the National Highway Traffic Safety Administration, 26.2% of the crashes studied involved vehicles with insufficient tread (at least 1/16th of an inch).
To protect yourself and your loved ones, it’s important to understand the role tire tread plays 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 inclement weather, such as rain, snow, ice or mud. Without them, cars would be virtually uncontrollable on wet, icy or slick roads.
Interestingly, if we only drove on dry roads, we wouldn’t need treads because smooth tires are best for gripping dry surfaces (that’s why NASCAR and other racing cars use tires without treads). But most of us drive in all kinds of weather conditions, so we need good treads in order to drive safely.
Tire treads are carefully designed grooves (channels) in the surface of the tire. They keep us safe by whisking 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. They also play a key role in making sure the car travels in the direction that we steer.
Why Driving on Bald Tires Puts You at Risk
Bald tires are a leading cause of accidents, especially single car accidents, for a variety of reasons.
- Increased risk of hydroplaning. Hydroplaning occurs when a layer of water gets between the tire and the road surface. The tire loses its ability to grip the road, causing the car to spin out of control. Modern tire tread patterns contain deep grooves that channel water away from the tire, enabling 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 balder the tire, the greater the risk of hydroplaning, even on roads that are only slightly wet.
- Unsafe heat buildup. Driving creates friction between your tires and the road surface, and as we all learned in 6th grade science class, friction creates heat. The faster you drive, the more heat the tire must be able to withstand – which is another reason to always have sufficient tread depth. Treads help cool the tire by allowing air to flow in between the grooves. Today’s tires are made to withstand high levels of heat. But when the treads wear down, the heat can climb to unsafe levels. Too much heat can cause a blowout, causing you to lose control of the car, especially at high speeds.
- Unsafe handling in snow or ice. Driving on a road covered with snow or ice can be a risky proposition unless you have good snow tires with plenty of tread. Your winter tires should also have “sipes” – small, thin grooves or channels cut into the edges of the treads that help improve traction by providing more surface area to grip the road. These days, many snow tires come equipped with snipes. If your tires don’t have them, a tire shop can add the extra edges for you. Keep in mind that as your tread wears away, so do the snipes. A lack of either one increases the odds of spinning out on icy roads.
- Loss of air pressure. Bald tires lose air faster than tires with good tread depth. Even if you check your tire pressure on a regular basis, low-tread tires can lose their air sooner than you think. Once your tires become underinflated, the risk factor significantly increases. Improperly inflated tires can’t grip the road properly, even in dry conditions, which can make it harder to steer your car. They can also impact braking by causing the car to skid during sudden stops. They even affect your bank account by reducing gas mileage (which drives up gasoline costs) and causing the tread to wear out quicker, which requires replacing the tires sooner than expected.
- Sudden blowouts. Thick treads help reduce the chances of suffering a blowout while driving. They can’t prevent all punctures, but if you run over a nail or other hard, sharp object, they stand a better chance than bald tires of resisting the blowout. Few moments behind the wheel are more frightening or dangerous that a sudden blowout at freeway speeds.
- Insufficient tread depth. When evaluating the tread depth on your tires, “eyeballing” it isn’t good enough. For a proper evaluation, invest in a tire tread gauge and keep it handy in your glove compartment. They don’t cost much and are simple to use. Or, you can insert a penny into the tread with the “heads” side facing you. If you can see all of Lincoln’s head, your tire no longer has enough tread for safe driving.
- Visible indicator bars. To make it quicker and easier to judge the amount of wear on your tread, today’s tires come with tread indicator bars. These flat rubber bars are built right into the tire, but are designed so that you can’t see them when the tires are new. As the tread wears down over time, the bars gradually become visible. When you can clearly see them, the tire tread has reached unsafe levels.
How to Tell if Your Tires Are Bad
Fortunately, it’s easy to tell when your tire treads are wearing low. The key is to inspect them on a regular basis. Tire professionals recommend checking them at least once a month. Here’s what to look for:
Bald tires aren’t the only danger sign to look for, as cracks in the sidewall also pose a threat. Although tire sidewalls don’t wear away like tread, 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 nothing to worry about. If you spot a large crack, head to your tire shop for a professional evaluation.
Older 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. Bulges and blisters should never be ignored!
Be Safe: Rotate and Replace
There’s a reason tire professionals recommend rotating your tires on a regular basis – it extends the life of the tire and keeps you safer by having the tread wear evenly on all four tires. All tire manufacturers include recommendations for how often to rotate your tires. If you lose the paperwork, simply call the tire dealership and ask. As a rule of thumb, plan to rotate your tires every six months or 7,500 miles. Your driving habits and local weather conditions may require more frequent rotation.
Sooner or later, your tires will need replacing. For safety’s sake, sooner is better than later. Never replace your tires based solely on the estimated lifetime mileage, as many factors affect how long a tire lasts. Instead, learn how to measure tread depth, check for other signs of tire damage on a monthly basis, and don’t delay when tread depth falls below 1/16th of an inch. Driving on bald 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.