How Long Do Tires Last and When Should I Replace Them?

As the sole connection between the ground and the car, a tire takes on a lot of responsibility. It provides grip, stability, comfort, and protection, among other things. With that pressure comes a bunch of outside forces that are constantly wearing on tires, breaking them down. Weather, road conditions, and age degrade the rubbers, chemicals, and plastics that make up a tire. 

Just how long that degradation takes is different from case to case, but there are a few general rules to follow. Most normal car tires last anywhere between 45,000 and 60,000 miles but that's not a hard rule. There are so many factors to consider, which is why this question requires a deeper dig to really solve.

The longevity of each tire will be different depending on the design and numerous wear-and-tear factors. Manufacturers and service companies suggest general mileage limits to help prevent driving on unsafe rubber. Given that most drivers put 12,000-15,000 miles per year on their car, and tires usually hold up for 45,000-60,000 miles, tires typically last anywhere between three and five years.

To get a more precise answer, it's best to check your specific tires' guidelines. Tires vary wildly in composition, with some using softer rubber for better grip and others using harder rubber as well as more ply to shoulder heavy loads or simply last longer. By looking up your specific make and model's life expectancy, you'll have a better idea of how long they'll last. And if they're wearing quicker than the manufacturer says they should, there's a chance something is wrong with your vehicle's alignment.

Discount Tire suggests replacing tires, regardless of the tread depth, after six years of use.

The U.S. Department of Transportation (DOT) requires that all tires must list the month and year the tires were produced on the sidewall. On tires made in 2000 or later, this can be found in the last four digits of the Tire Identification Number. Of those four digits, the first two convey the month and the last two convey the year. For example, a tire that reads DOT U2LL LMLR 3209 means it was made in the 32nd week of 2009.

Before 2000, three digits were used, with the first two digits translating to the month and the last digit marking the year.

Michelin states that a tire’s ingredient list features more than 200 raw materials. The main components include elastomers such as synthetic and natural rubber, reinforcing fillers such as carbon black and silica, plasticizers such as oils and resins, chemicals such as sulfur, and reinforcements such as steel and textile fabrics. Here’s the breakdown of the major parts of an average radial tire:

An innertube made of synthetic rubber that maintains the air pressure

Thin textile cords affixed to rubber that provide structure and support 

Located at the exterior “edges,” this is where the tire holds onto the wheel when rolling over the ground

Each wheel features two beads, or circular metal wires, that maintain an airtight fit with the rim of the wheel and keep the tire seated

The outside-facing section of tire that protects it from curbs and other damaging exterior forces

Providing a majority of the strength of the tire, the casing ply is made of up a bunch of tiny metal cords

What Michelin also calls the “zero degree belt,” the cap ply is made of rubber-covered reinforced nylon cords and maintains the tire’s shape while reducing heat 

The structural base of the tread

The tread is the pattern seen on the flat outside portion of the tire. In addition to this part of the rubber creating flash chemical bonds with the ground, the tread helps push away moisture and dirt from the surface of the tire. The tread is responsible for traction and grip, and without it, the tire can become slippery and unsafe.

A lot can go wrong with a tire, so it’s important to constantly check that it’s up to snuff. Look for and be aware of these factors when examining the health of your tires: 

Measured in pounds per square inch (PSI), this refers to the air pressure inside the tires.

This refers to how deep the patterned exterior ridges of the tire are.

Check for anything that has penetrated the tire and innertube that could cause air to leak out.

Look for cracks or splits in the tire. If found, the tire is not safe for driving and should be replaced immediately. 

Inflating a tire with too much or too little air will cause uneven tread wear and will detract from its full performance capabilities.

The mass distribution of tires needs to be even and balanced in order to function properly.