How to Know When to Replace Your Tires (And Where to Buy)

Tires don't last forever. They wear down, they age, and eventually they become unsafe — whether you've driven 60,000 miles or barely 20,000. Knowing when to replace your tires is one of the most important safety decisions you'll make as a driver.

The tricky part is that tires can look fine on the outside while being well past their safe lifespan. Age degrades rubber compounds from the inside out, and tread depth alone doesn't tell the full story. Here's how to know when it's time — and where to get the best deal on replacements.

Signs Your Tires Need Replacing

1. Your Tires Are Over 6 Years Old

Tire rubber degrades over time regardless of use. Heat, UV exposure, and oxidation break down the compounds that keep tires flexible and grippy. Most manufacturers recommend replacing tires after 6 years, and NHTSA considers 10 years the absolute maximum — even if the tread looks fine.

The problem is that age-related degradation isn't always visible. A tire can have plenty of tread depth but have hardened rubber that's lost its grip. This is especially dangerous in wet conditions where tire flexibility is critical for maintaining traction.

How to check: Every tire has a DOT code stamped on the sidewall. The last four digits tell you the week and year of manufacture. You can decode your DOT code instantly with TireSpy to find out exactly how old your tires are and whether they're still safe.

2. Low Tread Depth

Tread depth is the most obvious indicator. New tires typically have 10/32" to 11/32" of tread. The legal minimum in most US states is 2/32", but grip degrades significantly well before that point.

The penny test: Insert a penny into your tread groove with Lincoln's head facing down. If you can see the top of Lincoln's head, your tread is at or below 2/32" — replace immediately.

The quarter test: For a more conservative check, use a quarter instead. If you can see the top of Washington's head, your tread is at or below 4/32" — start shopping for replacements, especially if you drive in rain or snow.

3. Visible Damage or Wear Patterns

These are red flags that mean immediate replacement:

• Bulges or blisters on the sidewall indicate internal structural damage
• Cracks in the sidewall (dry rot) mean the rubber is breaking down
• Uneven wear patterns — cupping, feathering, or one-sided wear — suggest alignment or suspension issues that are also destroying your tires
• Exposed cords or belts — if you can see the internal structure, the tire is dangerously worn

4. Vibration or Handling Changes

If your car has developed a new vibration at highway speeds, or steering feels less responsive than it used to, worn or damaged tires could be the cause. While vibration can also indicate balance or alignment issues, it's worth inspecting your tires as a first step.

How to Read Your DOT Code

Every tire sold in the United States has a Department of Transportation (DOT) code molded into the sidewall. The full code contains the plant ID, tire size code, and manufacturer code — but the part you care about is the last four digits.

These four digits encode the manufacture date:

• First two digits = week of manufacture (01–52)
• Last two digits = year of manufacture

For example, a code ending in 2419 means the tire was made in week 24 of 2019 — roughly June 2019.

Finding the code can be tricky. It's often on the inner sidewall (facing the car), so you may need to crouch down or feel along the rubber. Look for the letters "DOT" followed by a string of characters.

Don't want to do the math yourself? Use TireSpy to decode your DOT code — enter the last four digits and get an instant safety verdict with your tire's exact age, manufacture date, and whether it's time to replace.

Where to Buy Tires Online

Once you know you need new tires, where should you buy them? Online tire retailers consistently offer better pricing than local shops, with the added convenience of home delivery or direct-to-installer shipping.

Tire Rack

The largest online tire retailer in America. Tire Rack has the widest selection of brands and sizes, competitive pricing, and a network of over 10,000 installation partners nationwide. They also provide detailed reviews, test results, and comparison tools to help you choose the right tire.

Browse tires on Tire Rack

Discount Tire

Discount Tire operates both online and through 1,000+ physical locations. They're known for price matching, generous return policies, and their own certificate program that covers road hazard damage. If you prefer seeing tires in person before buying, Discount Tire gives you the best of both worlds.

Browse tires on Discount Tire

Amazon

Amazon carries a massive selection of tires from virtually every brand, often at competitive prices. The main advantage is convenience — if you have Prime, you get free shipping, and Amazon partners with local installers through their Tire Installation service. The downside is less specialized guidance compared to dedicated tire retailers.

Compare tire retailers

What to Expect to Pay

Tire prices vary dramatically based on size, type, and brand. Here's a rough guide for a set of four tires, installed:

Compact and Sedan Tires (15"–17")

• Budget brands: $300–$500
• Mid-range brands: $450–$700
• Premium brands (Michelin, Continental): $600–$1,000

SUV and Crossover Tires (17"–20")

• Budget brands: $400–$650
• Mid-range brands: $550–$900
• Premium brands: $750–$1,300

Truck Tires (17"–22")

• Budget brands: $500–$800
• Mid-range brands: $700–$1,100
• Premium brands: $900–$1,600

Performance and Specialty Tires

• Summer performance: $600–$1,400+
• Winter/snow tires: $400–$1,000
• All-terrain (truck/SUV): $600–$1,400

These prices include installation, balancing, and disposal fees. Online retailers typically charge $15–$25 per tire for installation through their partner networks. Some retailers like Tire Rack include shipping free, while others may charge $10–$20 per tire.

Pro tip: Don't forget to factor in second-tier brands. BFGoodrich (owned by Michelin), General (owned by Continental), and Firestone (owned by Bridgestone) use similar technology to their parent companies at 20–30% lower prices. In many independent tests, the performance gap is minimal for everyday driving.

Check Your DOT Code First

Before you spend $500–$1,000+ on new tires, make sure you actually need them. Many drivers replace tires based on tread depth alone and miss the age factor entirely — or vice versa.

The smartest first step is a quick DOT code check. It takes 10 seconds and tells you exactly where your tires stand. Check your DOT code free with TireSpy, then make an informed decision about whether to replace now, monitor closely, or keep driving with confidence.