Car tires are something we tend not to think much about until something goes wrong. And when that day comes, the culprit is often a single tire. However, nobody wants to buy four tires when only one has failed.
Usually, tires on front-wheel-drive systems wear down faster. Therefore the tires on all/4-wheel drive systems need to match so that the tires wear evenly. Ideally, all your tires would match regardless of the driving system of your car.
While the short answer to this question is—yes, all four of your car tires need to match—it is more complicated than that. Considering that, according to the National Highway Traffic Safety Association (NHTSA), approximately 78,000 accidents occur annually due to flat tires and blow-outs, it is important to thoroughly understand your options when replacing old or dysfunctional tires.
What are the Dangers of Car Tires that Don’t Match?
Driving with faulty tires is no joke. The NHTSA reports that around 10,000 serious injuries and 400 deaths result from tire blow-outs and flat tires each year. What might save you money today could cost you your life tomorrow. The most common dangers of car tires that don’t match are:
- Increased risk of hydroplaning
- Increased intensity of hydroplaning
- Increased control issues in snow and rain
- Altered acceleration
- Negative effects on braking and stopping power
- Negative effects on cornering
- Negative effects on suspension
- Uneven pressure on a tire that may cause a burst or leak
- The decreased lifespan of tires
The risk of these dangers occurring depends on how dramatically your tires differ in quality, brand, size, tread depth, wear, and age. And as mentioned previously, special attention should be given to tire matching on all-wheel drive and four-wheel drive vehicles.
When and How Often Should I Replace my Tires?
Ideally, you should not wait until your tire bursts on the highway, or you wake up one morning to find that it’s flat and you have to replace it. Being proactive and checking your tires regularly will mitigate the danger of blow-outs, save you money, and help keep your vehicle in good health.
There are two important factors to consider when determining whether or not it is time to get new tires: tread depth and tire age.
First, let’s talk about tread. The treads of your tires are the network of grooves that dissipate water and help your car grip the road. You want these grooves to be deep. Think of the treads on the soles of your shoes. If you try to walk on an icy surface in smooth-soled dress shoes, you are going to slip much easier than if you are wearing snowshoes with deep tread.
So how can you check tread depth? Easy. All you need is a penny and a quarter.
After you fish some change out of your piggy bank, make sure to grab some gloves. You don’t want your hands to get covered in tire residue. Also, be sure your vehicle is parked somewhere safe where other cars won’t be passing by on the side of the car that you are checking. And finally, make sure the area is well-lit, or bring a flashlight.
To check your tread depth, kneel next to the tire you would like to examine. Next, take your quarter and place it down into a groove of the tread. Make sure that George Washington’s head goes into the tread wig first. His neck should be pointing upwards.
From George’s head to the edge of a quarter is about 4/32 of an inch. If the top of George’s head is not visible, then your tread is probably safe. However, if the top of his head is clearly visible, then it’s time to start shopping for a new tire.
If you noticed that George’s head was visible, then it’s time to use your penny. From Abe’s head to the edge of a penny is about 2/32 of an inch. Take the penny and place it in the tread as you did with the quarter—this time with Abe’s neck upward.
If you can see the top of Abe’s head, this means that it is time to purchase a new tire immediately. In most states, 2/32 of an inch is considered legally worn out. Consumer Reports has a great video demonstration of how to check tread depth with a penny and a quarter here.
Here is a chart to simplify things:
Length from head to the edge
2/32 of an inch
4/32 of an ich
If the top of the head is clearly visible, then…
Replace the tire immediately
Begin shopping for a new tire
Even if each of your tires passes the quarter and penny test, the NHTSA reports that most tire manufacturers recommend replacing your tires every 6 to 10 years.
You can check the manufacture date on your tire by reading the last four digits of the DOT Tire Identification Number, or TIN, on the tire wall. The first two of these numbers indicate the week of the year your tire was manufactured, while the last two numbers indicate the year.
For example, if the last four digits of the tire’s TIN number are 1107, that means the tire was manufactured in the 11th week of 2007, and you should get it replaced!
While the manufacture date is a decent indicator of when you should consider a replacement, there are other factors to consider. Tires, like people, live different lives. Some live fast, so they will wear out faster.
Here are some factors that will generally speed up the rate at which your tire ages:
- Exposure to sunlight
- Warmer climate
- Poor maintenance
- Improper storage
- Brake slamming
- Fast driving (heats tires)
- Consistently heavy loads (increase pressure)
- Improper tire alignment
Living in a Sun Belt city like San Diego means your tires will get doused with loads of UV light if they are not stored properly. Therefore, you should always be mindful of the rubber on your tires drying and cracking.
Even if you have a low-mileage vehicle that you infrequently drive, like an RV or passenger van, your tires are still at risk of deteriorating with age and exposure to the elements.
6 to 10 years is a wide range, so you should check the recommendations of your particular tire manufacturer and be sure to take your driving style and the local climate into account. In addition, check your tires regularly.
What Can I Do to Increase the Life of my Tires?
There are a few simple, easy, and cost-effective ways to maintain your tire and increase its longevity.
Tire Pressure Maintenance
Checking your tire pressure often and making sure that all of your tires are properly inflated is probably the easiest and cheapest way to get more mileage out of each tire. In fact, the NHTSA reports:
“Properly inflating your tires can save you as much as 11 cents per gallon on fuel. Yet only 19 percent of consumers properly inflate their tires. That means four out of five consumers are wasting money because of underinflated tires.” (Credit NHTSA website.)
In addition to saving you money on fuel costs, properly inflated tires may increase the life of a tire by 4,700 miles!
If you want to save money and increase the mileage of your tires, you can check your tire pressure with a tire pressure gauge. Tire pressure gauges are easy to find, and you can buy a decent one for around $5.
Tire pressure is measured in pounds per inch (PSI) or kilopascals (kPA). You need to check the proper PSI for your vehicle. The easiest way to check is to look in the manual that came with your vehicle. If you don’t have the manual, the PSI is usually posted on the driver’s side door edge or the B-pillar (driver’s side doorjamb) on newer cars.
Note that your vehicle may require different PSIs for front and back tires, and it is important not to inflate your tire past the maximum inflation pressure listed on the tire wall.
Now that you have your pressure gauge and you know your proper PSI, it is time to check the tire pressure. Here are the steps.
- Make sure the tires are about the same temperature as the outside air. Do not check your tires right after you’ve driven. Hot tires expand, so the reading would be higher.
- Find the valve cap. It looks just like a valve cap on a bicycle tire. Unscrew the cap, revealing the valve stem.
- Connect the pressure gauge to the exposed valve stem. It shouldn’t hiss! If you do hear a hiss, reposition the pressure gauge so that it is secure.
- Check the needle on your pressure gauge to read the PSI.
- Make sure to replace the valve cap!
If the PSI is lower than the recommended PSI for your car, you should inflate your tire. Most gas stations have air dispensers. Connect the air dispenser tube to the valve stem like you did with the pressure gauge, and feed air into the tire in short bursts. Check the PSI after each burst, and don’t forget to bring your pressure gauge with you!
The NHTSA reported that in 2017, 738 people died front tire-related crashes. Maintaining proper tire pressure is not just about saving money; it’s also about safety.
Balancing your Tires
Now that your tires are all nice and plump, it’s important to make sure they are rolling smoothly. We’ve all struggled to push a shopping cart with one funky wheel down the grocery store aisle. Making sure your tires and balanced and aligned helps ensure that your tires roll smoothly and evenly.
Unbalanced tires cause your tires to wobble, which causes the sidewalls of your tires to wear more quickly. The extra wearing also increases the risk of a blowout.
If a front tire is out of balance, you will probably start to feel a little vibration in the steering wheel, like the handle of a wacky shopping cart in your hand. For the back tires? You’ll feel a vibration on the seat floor.
Balancing tires is a common tune-up. The technician adds weights in different areas around the tire so that the weight is evenly distributed. The average tire balance runs about $40 and should always be done when replacing a tire.
Tire alignment is about more than just your car’s tires. It concerns the suspension of your vehicle system and the angle at which your tires are set against the road.
If you have ever momentarily let go of your steering wheel and felt your car veer into the next lane, then you have had a tire alignment issue. Another clue to poorly aligned tires is uneven tread—if the tires are angled poorly, the tread begins to wear differently on opposite tires.
When you take your car in for an alignment, the technician will check three things.
- Camber: Camber issues occur when your wheels are angled excessively inward (negative camber) or outward (positive camber). You do not want an outward-angled tire despite it being called ‘positive’.
To get a better sense of positive and negative camber, imagine you are standing in front of a car looking at the driver. If the tops of both tires lean outward further than the bottoms, forming a ‘V’ shape, this is positive camber. The opposite is negative camber.
- Toe: This is when your tires are duck-footed (toe-out) or pigeon-toed (toe-in). Imagine trying to run a long distance while maintaining a duck-footed or pigeon-toed foot posture. It’s probably not great on the knees, and it’s also not great for your car’s tires or your car in general.
- Caster: If you’re the type of person who loves drifting around corners, you are going to want to pay attention to caster issues. The caster angle aids balance and stability. When the steering axis is tilted too much toward the driver, it is called a positive caster, and if it’s tilted too much away from the driver, it is called a negative caster.
Each of these factors can cut valuable mileage out of your wheels. Making sure your car is properly aligned is an investment. An average wheel alignment will run you about $98.
It is a good rule of thumb to have your tires rotated with the same frequency that you get your oil changed. That’s around 5,000 miles unless otherwise instructed by your car manufacturer. If you can start off getting both services accomplished at the same time and always get them done together after that, you’ll save yourself a lot of trips to the mechanic.
For some cars, you need to make sure to get your tires rotated regularly in order to keep the vehicle under warranty. Taking your car in for tire rotation is a great time to get your tires checked out for things like tread wear, alignment, and tire pressure.
Different tire rotating patterns depend on whether your car is four-wheel drive, all-wheel drive, or front-wheel drive. The size of the tire and the directionality of the tire is also important. Your technician should be able to advise which pattern is best suited for your vehicle. However, if you would like to learn more about tire patterns, there is an in-depth article about them on Bridgestone’s website.
Choosing the Right Tire
Your tires will eventually blow out, flatten, or simply age out. When you are ready to buy new tires, you should consider your local climate, the size of the tire, the tire rating, and the age of the tire.
First, let’s take a look at what type of tire you are going to need. While there are more than four types of tires, the most commonly used tires are those shown below.
- All-season tires: These tires come with speed ratings of S (112mph) and T (118mph). They are designed to perform in any season and climate (considering that the weather is not particularly extreme—heavy snow). They are not quite as good as winter tires in the snow, but they offer versatility, and they perform well in slush and rain. You can use these tires on mainstream cars, SUVs, and pickup-up trucks.
- Winter tires: Also known as snow tires, you can identify these tires by a mountain and snowflake symbol stamped on the tire wall. Their tread patterns increase grip, and their softer rubber build means that these tires are designed for superior control on ice and in snow. It’s best to buy these tires as a set of four. You don’t want any issues when you are driving on ice and in snow.
- Summer tires: These tires are great if you live in a hot, sunny region with a lot of hot asphalt. They also perform well on wet roads. Summer tires are known for providing that extra bit of control to high-performance vehicles like sports cars. Don’t buy these tires if you live in the Colorado mountains or any other place that gets a lot of snow.
- All-terrain tires: If you like to take your car off-road, then these are your tires. These tires will make the ride a little less smooth than all-season tires, but they are great for switching between the road and more rugged terrain in a four-wheel-drive vehicle.
If you want to learn more about less common tires, like high-performance tires, check out this great Consumer Reports article.
The United States government rates tires based on several factors. This rating system is called the Uniform Tire Quality Grading Standards or UTQGS. You can find the rating on the sidewall of passenger vehicle tires in the United States.
Traction and temperature grades are rated A (highest) to C (lowest), with traction having an extra category, AA (higher than A). A number represents the rate at which the tire is expected to wear out. Let’s break it down:
- Treadwear: This is how long the tread on your tire is expected to last. Treadwear is represented by a number, with 100 being the standard government-mandated treadwear. The higher the treadwear number, the longer it takes for the tread to wear down.
For example, a tire with a grade of 600 would be expected to have tread that takes up to 6 times longer to wear down than the tread on a tire with a rating of 100. A tire with a treadwear grade of 200 would have tread that would wear down twice as slowly as a tire with a treadwear grade of 100.
- Traction: This represents the tire’s efficacy on wet roads. For example, a tire with the highest grade of AA has the ability to stop more quickly on wet pavement than a tire with a grade of C.
- Temperature: This represents the tire’s ability to resist heat, with A representing a tire that is optimized to resist heat and C representing a tire that is less resistant to heat.
The UTQGS tire rating on the tire wall will look something like this: 400AB. This means that the treadwear will theoretically wear out four times as slowly as a tire rated 100, the traction is rated A (second best after AA), and the temperature is rated B (second best after A). Therefore, the numbers and letters represent, from left to right: treadwear, traction, and temperature.
The size of the tire you need depends on your vehicle. Simply check your owner’s manual. If you don’t have the manual, you can find the tire size on the driver’s side door edge or post—the same place you checked for the tire’s PSI.
It is not recommended to buy used tires. They may have defects that are not immediately noticeable, and you may end up paying more in the long run if it blows out on you. However, you usually are not going to buy a tire that has been manufactured on the day of purchase.
For this reason, it is important to always check the manufacture date of the tire (mentioned earlier). Recall the TIN number on your tire wall represents the manufacture date. The first two numbers are the week the tire was manufactured and the final two numbers are the year it was manufactured.
Where Can I Buy a New Tire?
There are plenty of well-known and large tire chains like Discount Tire and Big O Tires. But did you know that you can also buy tires from Amazon? And that means that if you have Amazon, Prime you may be able to get two-day shipping. Also, Amazon has the advantage of having thousands of reviews on its products.
Another great place to buy tires is at Costco. Of course, you will need a Costco membership card. One great thing about buying tires from Costco is that they have an annual “buy four tire,s” deal which offers $70 off any set of four tires with 1 cent installation per tire! Check out the deal on their website.
What if I Can’t Afford to Replace my Tires at the Same Time?
Now, maybe you’ve made it through this entire article, but you are still thinking, “Well, all of this information is great, but I’m still broke right now. I simply can’t afford to buy all four tires at the same time.”
You are not alone. If your only option is to replace a single tire, there are some things that you can do to make it as safe and effective as possible.
First, make sure that your newer tires are placed in the rear. It’s safer to have newer tires on the back because deeper-treaded tires hold up better to hydroplaning.
While your front tires may still hydroplane, it is better that your front wheels hydroplane than your back tires because it is easier to control. This is called understeering.
Oversteering is more dangerous and happens when your back wheels begin to hydroplane before your front wheels. Your back wheels are not attached to your steering wheel, so it is harder to regain control front-wheel drive car; the gas pedal does not control the speed of the back tires.
Your replacement tire should be paired with the tire that has the best tread depth or the newest of your old tires. It’s important to have tires paired with others that have similar wear.
Of course, the best way to save money on tires is proper tire maintenance. However, if your tire is already blown-out, maintenance advice won’t cut it.
Besides carefully researching and comparing tire prices, becoming buddies with your local tire dealer or auto shop mechanic, or waiting for a sale, you could look for tire rebates.
Many tire dealers offer rebates. A rebate is a discount that you receive after purchase. You send in a form and, your receipt and a few weeks later, a rebate card will be sent. Most rebate cards can be used like cash in various stores.
While there are always deals to be found or ways to skimp on paying for a full set of tires, if you can buy a full set, it will end up saving you money in the long run.
Practicing proactive tire maintenance is still the most effective way to save money on tires.