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 multitude of outside forces that are constantly wearing on tires and breaking them down. Factors such as 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. The Drive’s crack informational team has put together a handy guide to show you the way and answer the question, “how long do tires last?” 

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:

Inner liner: An innertube made of synthetic rubber that maintains the air pressure

Carcass ply: Thin textile cords affixed to rubber that provide structure and support 

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

Beads: 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

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

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

Cap ply: 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 

Crown plies: The structural base of the tread

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.

The length of each tire’s life will be different, depending on the design and numerous wear-and-tear factors, but manufacturers and service companies suggest general mileage limits to help prevent driving on unsafe rubber. Check your manufacturer warranties and guidelines for specifics.

Discount Tire, a large nationwide auto service company, suggests replacing tires, regardless of the tread depth, after six years of use. That time could come sooner, depending on the health of the tires. Every tire also has a suggested mileage limit.

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 newer, 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.

The best way to inspect tires is to remove them for a full view of the front and rear sidewalls, as well as the tread. Use these items to ensure you’re working safely.

Checking, rotating, and changing tires are straightforward tasks, but they involve lifting 3,000-6,000-pound chunks of metal and plastic above the ground. That makes it dangerous. The right tools provide safety and simplify the job, so here's what you'll need to check your tires.

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Organizing your tools and gear so everything is easily reachable while you are inspecting your tires, will save precious minutes waiting for your handy-dandy child or four-legged helper to bring you the sandpaper or blowtorch. (You won't need a blowtorch for this job. Please don’t have your kid hand you a blowtorch—Ed.)

While you are asking the Gods "How Long Will My Tires Last?" - you’ll also need a flat workspace, such as a garage floor, driveway, or street parking. Check your local laws to make sure you’re not violating any codes when using the street because we aren’t getting your ride out of the clink.

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: 

Reading will only take you so far. It helps to have someone actually show you how to do things. That's why we've attached this video by 1A Auto. It covers how to measure tread depth with both a dedicated tool and a penny. Remember that tread depth is only part of the story, though. As you check it, checking for cracking, severe wear, and other signs of damage is a must.

Got a question? Got a pro tip? Send us a note: guidesandgear@thedrive.com