Tires are one of those things that can make or break a car. As far as safety goes, tires are arguably the most important part considering they’re the only thing keeping you on the road. In our Tire Basics series of Tech Talks, we’re going to break down everything you need to know about tires.

How They’re Made:

Modern tires are designed to be used without a inner tube. In order to ensure that they keep air throughout their life and as they wear down, they are constructed to multiple layers. Most tires consist of multiple layers of belts, or metal wire reinforcement, between the inner liner and tread layers. They also have a hard metal lining around the inner edge of the tire called the bead. This is meant to give wheel-contacting edge the ability to create an airtight seal by giving it some rigidity.

Tire treads are made up of thicker layers of rubber which have grooves which allow the car to maintain traction. As you drive, the part of the tire that makes contact with the road slowly wears out. A common feature of tire treads is siping, or a series of thin cuts in the tread in order to force water out of them. Tires designed for harsher weather, such as snow, will feature more siping while tires designed for use during dry condition will not.

Different Types of Tires:

The most common types of tires are winter, summer, and all season.

Winter Tires: 

Winter tires are often made of softer rubber than normal tires. This is because cold temperatures tend to make rubber more stiff, and being able to flex is essential in maintaining grip. However, this makes winter tires wear down abnormally fast if used in dry conditions. While some people may find it convenient to put snow tires on early, this practice can drastically decrease the life of the tires.

Summer Tires:

Summer tires are designed to work best when they’re hot. That’s why they often feel harder than normal tire when they are new. As you drive, friction will heat up the tires and make the rubber more flexible. This in turn gives the tires better ability to conform around the road surfaces and give you grip. Summer tires often have less siping and shallower tread than winter or all-season tires, which gives them more overall contact surface with the road. While summer tires are great on sports cars, they are not recommended for demanding track applications. They also tend to wear faster, so if you live in a climate with snow, it is best to keep a set of winter or all-season tires as well.

All-Season Tires:

Yes, the name does say all-season, but don’t let that fool you. All-Season tires can be used in snow, but they are not designed for it. They are generally made of harder rubber than winter tires, which allows them to wear down like normal tires, while their siping allows them to work very well in wet conditions. This means that when temperatures drop, they become much harder than winter tires, which reduced their effectiveness in snow. Additionally, they don’t have as much siping as winter tires, which does not let them evacuate snow buildup as well. However, they generally last longer than summer tires and are cheaper, which makes them a great option to alternate with winter tires.

Tire Damage and Maintenance:

Punctures: 

I’m sure most people who have been driving for a while have experienced a puncture, or known someone who has. There is so much debris on the roads and it’s pretty common to run over a stray nail that leaves you with a flat on the side of the road. Good news is many punctures are perfectly repairable. If the object is small enough (which it often is) and the damage is within the shoulders of the tire, any tire shop can repair it. However, there are a few things to keep in mind.

When you’ve noticed a puncture, immediately change out the tire. Driving while a tire is flat is not only dangerous, it damages the tire. It causes the inner lining of the tire to flex too much and take on too much weight, which breaks them apart. Most cars come with either a small or full size spare tire in the trunk or underneath the car.

Impact Separations:

Impact separations often appear as bulges in the tire. They occur when the tire impacted something with enough force to separate the inner layers of the tire. The bulge happens when the weakened rubber, usually on the sidewall, no longer has its rigidity and the air forces the rubber out. There are not repairable and the tire needs to be replaced immediately. Whenever you feel your tire had a hard impact, like running over a pothole, check both the outre and inner sides for bulges.

Uneven Wear:

Uneven wear occurs when the car’s suspension puts an uneven weight on on side of the tire. This causes that side to wear down faster. There’s not much that can be done to the tire, but an alignment can go a long way. Think about it, a set of tires usually cost upwards of $400 while an alignment only costs $100 on average. If you don’t check your tires often, make sure to get them rotated often. Tire shops will often warn you if they notice uneven wear.

Every tire has a triangular wear indicator along the shoulder. If the tire wear is close or past the indicators, replace the tires immediately. Excessive tire wear can cause the car to lose control more easily and greatly increases braking distance.

Tire Life:

A tire’s life ends when there is irreparable damage, the tread wears below the safe limit, or until they’ve aged between 6 to 10 years.  The age at which a tire should be replaced is different between manufacturers. Some tires can last up to 10 years. However, it is important to pay attention to the wear characteristics of older tires. Often times, small cracks along the sidewall of the tire can be visible. This is a major indicator that the tire is drying out and should be replaced. If the cracks get deep enough, not only can they leak air, but they can compromise the integrity of the tire. Blowouts are  likely at this point.

Proper Air Pressure:

Most cars come with a recommended tire pressure, which can be found on a sticker along the inner edge of the driver’s door. The most common air pressures are around 35 PSI. Many tire shops, such as Discount Tire and America’s Tire, offer free air checks. If you are filling air yourself, make sure to check the door card. Some cars, mostly performance or luxury cars, recommend a different air pressure for the front and rear tires.

Improper air pressure can often result in uneven wear. When the pressure is too high, the center of the tread bulges out and wears out faster. When the pressure is too low, the tire flexes more which causes the outer edges to wear faster.

Rotation and Balancing:

Most tire shops recommend rotating and balancing the tires around every 6,000 miles. These services are often offered for free by the store you bought your tires from. Some car manufacturers recommend different rotation schedules, but they only apply to the original tires.

Rotations consist of removing the wheels and tires from the car, and placing them in a different configuration in order to wear the tires evenly. For example, if your commute involves primarily left turns, your right side tires will wear faster. By rotating them consistently, you effectively even out the wear. Balancing involves rotating the wheels on machines that can detect vibrations and attaching weights to counter the vibrations. This can also help increase tire life, but it is most effective at reducing uncomfortable vibrations.