How to Know When to Replace Tires

How to Know When to Replace Tires
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It’s unlikely you spend much time thinking about it, but how often should you change your tires? You may not think about it at all until you’re sitting on the side of the road after a blowout. Maybe this time you’ll be lucky and have roadside assistance, but an ounce of prevention is worth a pound of cure. Here’s how to spot the signs of wear and tear on your tires so you can replace them before experiencing a massive (and potentially dangerous) inconvenience.

How often should you replace your tires?

Unfortunately, tires don’t have set replacement schedules like air filters or motor oil. Instead, their longevity depends on a combination of how fast they wear out, how many miles they’ve traveled and how old they are. It’s important to consider all three when determining when to replace your tires.

Wear

Because tires are in contact with the road, they’re at the mercy of the forces of friction—the more you drive, the more material gets worn away. Today’s tire manufacturers have tread-wear indicators called “wear bars.” Wear bars are strips of rubber manufactured into the tread that show up when it’s absolutely time to replace your tires. If you see three or more wear bars, it’s time to change your tires immediately.

Mileage

Most modern tires call for replacement every 25,000 to 80,000 miles. Typically, the more performance-oriented the tire, the fewer miles they need to travel before being replaced. Performance tires are softer in order to better grip the road in high-speed conditions, and thus degrade faster than harder, touring-style tires.

Age

Tire manufacturers such as Goodyear, Michelin and Bridgestone recommend replacing tires before they’re six years old, even if you haven’t gone near the mileage limit. Tires degrade from exposure to sunlight, pollution and chemicals. So even if you’re someone who doesn’t log many miles each year, you should probably consider replacing them before they wear out because of the tires’ age.

Why do tires need to be replaced?

No mechanical part lasts forever, and tires are no exception. And should you ignore basic maintenance like rotation, alignment or air pressure, their expiration date could come quicker than anticipated—possibly at an inopportune time in the form of a flat or blowout. Regardless of why a given set of tires may need to be replaced, they eventually will—and failure to do so may expose you to the following risks while driving.

Decreased traction

Your car’s contact with the ground is roughly the size of your hand. Believe it or not, those contact points don’t actually require tread of any kind to do their job on dry roads. Other than some heat generation issues due to tire treads’ cooling effect, tires with no tread can still contact the road.

However, with slick tires, you’ll experience the inability to control your car when there’s rain, snow, or ice. If you watch Formula 1 racing, you’ll notice that the crews immediately switch to grooved wet-weather tires when conditions get wet. Water can’t be compressed and needs to be pumped out of the way. When properly treaded tires roll over wet roads, the water is redirected into channels that allow the rubber to contact the pavement. At this point, tread depth is critical, and the deeper, the better.

Poor braking and steering

You’ve probably experienced the crisp and quick steering that comes from new tires. And the feel of new tires in corners, rolling smoothly and stable, gives confidence. As a tire wears, the ability to stay cool from the friction on the road degrades due to the loss of rubber on the tire. The tire will lose the ability to cool as the tread wears. A hot and slick tire can cause problems with braking and steering, for example, you won’t be able to stop as quickly or take corners tightly at speed.

More susceptible to puncture

When the tread disappears on a tire, so does its protection. A slick or heavily worn tire has very little rubber between the road and the air inside of it. Even a small nail can cause a puncture, and road debris could cause a blowout.

How to tell when to replace tires

When you take your car to be serviced, the mechanic will assess your car’s components, and one of those will be your suspension and tires. This is a good time to determine whether you need new tires. You can also regularly check on air pressure, tread wear and whether or not you’re feeling vibrations through the steering wheel. Here are some common signs that might indicate it’s time to replace your tires, and how to try and spot them.

Tread depth

Wear bars are a final warning that your tires are in desperate need of replacement, but really they should be replaced well before that point. You want a minimum of 232 of an inch, and an easy way to try and check is to grab a penny and follow three quick steps.

  1. Hold the penny so that Abe Lincoln’s body is between your thumb and forefinger.
  2. Place the penny, leading with Abe’s head, into one of the grooves.
  3. If the groove hides any part of Lincoln’s head, then you’re running at a legal depth. If all of his head is showing, you’re below the legal depth of 232 of an inch, and you may have trouble safely driving in rain or other inclement weather.

Having legal treads doesn’t necessarily mean your tires are safe. If you’re even close, consider replacing your tires soon.

Vibration

Vibrations can happen for various reasons, but they often have to do with tire balance or suspension alignment. As tires wear and lose rubber, they can become less round, causing vibrations as they roll on the road. If you feel those vibrations through your steering wheel, a trip to the tire shop might be in order.

Also, depending on how many rocks, potholes, or curbs you hit, suspension parts can become bent or worn, which causes the tire to wear unevenly. You’ll notice unusual wear on the tire, which is a sign of alignment issues and should be checked out by an alignment specialist.

Bulges

If you hit an object on the road, a curb, or a pothole, the tire can have a bulge on the sidewall. Unlike the bottom of the tire, a sidewall doesn’t have composite or steel belts protecting it and is more prone to internal structure failure. A bulging sidewall could cause your tire to explode while driving on the highway. If you can put your spare tire on and take the damaged tire to a tire shop, then do it. If not, then drive carefully to your nearest mechanic or tire shop.

Punctures in the sidewall

If a nail is embedded in your tire but not in the tread area, you’ll need to replace the tire. Strong composite cords make up the tread structure, but the sidewall doesn’t have the same cords. A plug can’t fill a hole in the sidewall, since this part of the tire flexes so much while absorbing shock. The patch won’t hold, and the tire will continue to leak or cause the tire to have a dramatic failure and blowout.

Seasonal changes

If you have summer tires and winter is coming, you’ll need to replace them with winter tires. The tread on summer tires is made for warmer weather and, in winter, will become inflexible and lose grip. Winter tires’ rubber compound stays flexible, and the treads are designed to provide maximum traction in snow and slush. Conversely, you’ll need to do the same when summer rolls back around.

Hydroplaning

You may not think much about having to swerve or brake suddenly in wet weather. But if your tires are too worn, you may hydroplane. Hydroplaning is when the tire rides on top of the water because your lack of tread doesn’t give the water anywhere to go. If you feel any slipping of the tires in the rain or have longer stopping distances, it’s time to replace them.

Visible damage

If you see a bent wheel, cut in your sidewall or have a habit of not slowing down for potholes, you’ll need to replace your tires. Bent wheels keep the tire from fitting properly on the rim, and damage to the sidewalls can weaken a tire’s structure.

How to choose new tires

After investigating your tires, you’ve probably decided that they need to be replaced. What tires do you get? Luckily, with just a bit of preparation you can help move things along when you get to the tire store.

Find the right size

Locating the correct size is easy. You’ll find it on the sidewall or the sticker on the driver’s side door frame. The tire size would be in this format: P 255/55/17S 82. Here’s how to decode it:

  • Tire type: “P” means “Passenger tire” or “LT” for “Light Truck/SUV tire.”
  • Tire width: “255” is the width of the tire at its largest inflated point, in millimeters.
  • Aspect ratio: “55” means that the tire sidewall height is 55% of the tire’s width.
  • Wheel diameter: “17” is the rim diameter.
  • Speed rating: “S” is the speed rating related to how fast the tire can safely travel on different vehicle types.
  • Load rating: “82” is the load rating, a numerical code that correlates with the tire’s maximum safe load.

How to read the code on a tire's sidewall.

Determine the style you need

You rely upon your tires to allow you and your passengers to travel safely. In order for them to do their job effectively, there are multiple style options depending on your vehicle type, the kind of driving you do and the conditions you’re likely to encounter.

Car and CUV tires

Passenger: These tires are designed and built for a broad range of cars and SUVs. They provide a very smooth and quiet ride and a long tread life. When maintained correctly, some brands will provide 60,000 miles of service. These tires will fit most of your needs, although all-season tires may be better for you.

Summer tires: Performance-oriented summer tires will work in dry and wet conditions. Summer tires are at their best in warm weather and are not all-season, meaning you may lose some traction in lower temperatures, even if the tire is in otherwise good condition. Their design is optimized for summer grip and handling.

Touring/all-season tires: All-season tires are designed to provide all-around comfort and handling in all seasons. Although not a snow tire, all-season treads work well in dry and wet weather. Passenger cars and many SUVs come standard with these types of tires.

Performance tires: High-performance tires have lower aspect ratios, higher speed ratings, larger grooves and a softer tire compound for better grip. These tires will, however, wear more quickly because of the softer compound.

Run-flat tires: Run-flat tires have a reinforced sidewall that stays rigid, keeping the tire in place without air pressure. Many manufacturers use run-flat tires in sport car applications because of weight savings gained by not needing a spare. If you have run-flat tires, you can drive even after a puncture. This will give you time to locate a mechanic or tire shop. Most of these tires will allow you to drive for up to 50 miles at 50 miles per hour, even after you’ve lost all air pressure.

Truck and SUV tires

Because of gross vehicle weight, towing capabilities and off-road use, you may find the need for more aggressive and better-reinforced tires. Here are some tire choices to consider.

All-terrain: All-terrain tires are designed with larger tread blocks and aggressive looks to provide traction and safety during off-road driving conditions. Four-wheel drive, off the road–focused SUVs and pickups are often fitted with these. Even though they look aggressive and off-road only, their design provides a stable and comfortable ride on the highway with minimal noise. Although designed for gravel, dirt or mud, their longevity isn’t impacted by highway driving.

Mud tires: Made primarily for off-roading, these higher-load-rated tires are reinforced for resistance to punctures and damage. Although excellent in mud and sand, they aren’t effective for highway use because of noise and reduced traction.

Light Truck tires: Light Truck tires are similar to all-season tires but have a higher load rating for the heavier loads carried in trucks and SUVs. They provide the same comfort and handling in all seasons, but have stiffer sidewalls that better support weight.

Figure out your tire budget

After you decide on the style and size of the tires you need, it’s time to look at the budget. Based on the size, type and application of a tire, you may have already figured out that there’s going to be a wide range of prices—even among the same manufacturer.

Is there a hard and fast recommendation on how much you should spend? No. But it is important to remember that your tires are your only direct connection to the road. So safety and protection should be at the top of your consideration list. Staying with an established brand is a good idea, and staying with a tire appropriate for your car would be the second consideration. For instance, it wouldn’t be advised to put off-road truck tires on your sedan. A tire professional can give you some good advice on model appropriate tires.

Do I need to replace my spare tire, too?

Yes. With a spare, unless you’re driving around on it for an extended period of time, age will be the biggest consideration. For cars, the tire is in the trunk area and protected, though it can still become cracked and brittle over time. If you have a pickup, it’s most likely that your spare tire is under the pickup bed and exposed to the elements. When you purchase new tires, having the technician check the spare for age-related cracks or damage is recommended.

Can I rotate my tires instead?

Tire rotation is an important component of extending the life of your tires and decreasing wear, but it’s not a substitute for replacement when the time comes. While driving, your tires will normally develop uneven wear patterns. By rotating the tires every 5,000 to 7,000 miles, you’ll extend the life of your tire and save considerable amounts of money.

In most cars, front tires will bear the weight of the engine and the turning force. This causes the tires to wear more quickly than the rear. By moving the rear tires to the front, you’ll equalize the wear patterns and have a smoother and noise-free ride. It’s also important to note that tire manufacturers will require tire rotations to keep the warranty valid.

However, without a floor jack, jack stands and balancing machine—plus the knowledge needed to work them—tire rotation is best left to a professional.

Do all four tires need to be the same brand?

No. But some things are important to do when getting new tires.

  • The tire size should be the same. If you have 24550-18 tires, replace them with the same size.
  • Speed rating: Replace your tire with the same speed rating as the other tires. If your tire is a W speed-rated tire approved for speeds up to 168 miles per hour, you should never replace it with a tire of a lower speed rating. Tire construction and handling capabilities need to be the same for proper control of your vehicle.
  • Tread type: It’s recommended that you don’t mix different treads on the same axle. If you have a certain type of Bridgestone tire on the front tires, the replacement tire should be the same. Also, depending on the wear of the other tire, you may need to replace both.

Although it’s easier to replace all four tires, it’s okay to replace your tires in pairs. It saves money and still makes the vehicle safer.

How can I make my new tires last longer?

Tires don’t last forever, but some simple best practices can help them reach their full potential.

Keep the correct tire pressure

Although it’s important to visually check your tires each week, it’s tough to see a 5 psi loss of air pressure. You’ll need an easy-to-read digital tire pressure gauge to inspect your tire pressure at least once a month. Examine the tires when they’re cold, preferably in the morning, because air will warm up in the tires within miles of your house. And warm air expands, which will give an inaccurate reading at the gas station.

Cold tires will give you the best reading, regardless of the weather. checking your tires’ air pressure once a month might seem like a lot of trouble, but tires can lose two pounds of pressure in one month. Over a year, that adds up.

Rotate your tires every 5,000 to 7,000 miles

Rotation promotes even wear and extends your tire’s tread life. If you have a full-sized spare tire, include it in the rotation. It’s like a bonus tire. This gives you five tires and further extends your overall tire life.

Improve your driving

If you have a tendency to speed and make fast turns, you’re wearing down your tires’ tread more quickly than a more reserved driver. By improving your driving habits, especially laying off those fast corners, you’ll be saving yourself money in the long run.

If you drive safely, but happen to hit your share of curbs when parking, you’ll also want to brush up on your parking skills. Any scraping against cement or crashing into curbs will risk breaking down your tire or causing failure. Improved driving habits are a no-cost way to extend the life of your tires.


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Disclaimer: The above is solely intended for informational purposes and in no way constitutes legal advice or specific recommendations.