Do I Need New Tires? Tread Depth, Tire Age and Damage Signs

Last updated Oct 31, 2026. Sources were opened on Oct 31, 2026, except the four rebate forms, which we read on Oct 27, 2026. All are linked in the text.

Most people ask this when a shop tells them they need tires, or when the car starts feeling different in the rain. You can do a first check yourself in about ten minutes with a coin and a flashlight, then have a tire shop confirm anything that looks off. Here is what the safety agencies, tire makers and testers say, with links so you can check us.

Free tool: Tire Check lets you enter the date code, tread reading and any damage for each of your tires and gives a plain red, yellow or green result with the reasons. It runs in your browser, with no sign-up.

The short answer

Replace a tire now if any of these is true:

• The tread is down to 2/32 of an inch, or the tread wear bars are flush with the tread (NHTSA).
• It has a bulge, blister or cut in the sidewall. Michelin says sidewall damage can't be repaired (Michelin).
• It was made more than 10 years ago. Michelin and Bridgestone both recommend replacing tires, spares included, 10 years after the date of manufacture, however much tread is left (Michelin; Bridgestone).
• It has a puncture that can't be properly repaired (more on that below).

Start shopping, without panicking, if the tread is around 4/32", if the tires are more than five years old, or if you see cracking or uneven wear.

Tread depth

Tread depth is measured in 32nds of an inch. Consumer Reports says a typical new all-season tire has about 10/32" of tread (Consumer Reports).

• 2/32": NHTSA says tires "are not safe and should be replaced" at this point (NHTSA). AAA notes it is the legal minimum in most states (AAA). Tires have built-in treadwear indicators, small raised bars in the grooves; when the tread is level with them, the tire is at about 2/32".
• 4/32": Consumer Reports suggests starting to shop at about 4/32", before braking and wet-weather grip drop off much more (Consumer Reports). In AAA's testing, all-season tires worn to 4/32" needed on average 87 more feet to stop on a wet road than new ones in a passenger car (AAA).
• Snow: in Consumer Reports' tests, half-worn all-season tires (about 5/32" to 6/32") lost about 14% of their snow traction and stopped about 7% longer in the wet. Its advice for snow-belt drivers is to have at least 4/32" in the middle of winter (Consumer Reports).

The penny and quarter tests

1. Pick a main groove, ideally in the middle of the tread, and also check the inner and outer grooves.
2. Penny: put it in head-down with Lincoln facing you. If you can see the top of his head, the tread is at 2/32" or less and the tire needs replacing (NHTSA).
3. Quarter: put it in head-down. If you can see the top of Washington's head, you have less than about 4/32", and it's time to start shopping (Consumer Reports).
4. Check a few spots on each tire. If one edge reads lower than the rest, see uneven wear below.

A tread depth gauge costs little at an auto parts store and is easier to read than a coin. Tire Check takes either a gauge reading or your coin result.

Tire age and the DOT date code

Tires age even when they aren't driven much. NHTSA says the rubber and other parts change over time, and that people who own RVs, collector cars or other vehicles they don't drive often, or who drive few miles a year, are more at risk. Heat and sun make it worse. You can't see tire aging just by looking (NHTSA).

Reading the code. The tire identification number on the sidewall starts with "DOT". Under federal rules, its last four digits are the date code: the first two are the week and the last two are the year (49 CFR 574.5). So 2419 means the 24th week of 2019. The full number may be on only one side of the tire (NHTSA). Tires made before 2000 used a three-digit code, so a code like 329 means the 32nd week of a year in the 1990s, or possibly the 1980s (Bridgestone safety manual).

What the age guidance says.

• Michelin recommends a thorough inspection by a tire professional at least once a year after five years of use, and replacement 10 years after the date of manufacture, including spares (Michelin).
• Bridgestone recommends a professional inspection after five years of use and replacing all tires, spares included, made more than 10 years earlier, even if they look usable (Bridgestone).
• NHTSA notes that some vehicle and tire makers recommend replacing tires that are six to 10 years old regardless of tread wear (NHTSA). Check your owner's manual for your vehicle maker's own figure.

These are manufacturer recommendations, not laws. Ten years is the outer limit, not a target; many tires wear out or get damaged long before then.

Damage you shouldn't ignore

• Bulges, blisters or cuts in the sidewall. Bridgestone says bumps or bulges may mean a separation inside the tire (Bridgestone). Michelin says sidewall damage can't be repaired (Michelin).
• Cracks. Fine surface cracks can be an early sign the rubber is drying out. Michelin says significant cracking, especially cracks that open when the tire is flexed, means the tire is no longer safe to use (Michelin).
• Uneven wear. Wear on one side of the tread or flat spots can point to a tire or vehicle problem such as alignment or inflation (Bridgestone). NHTSA lists irregular wear among the reasons to stop using a tire (NHTSA).
• Changes you can feel. Vibration, pulling or handling changes can mean uneven wear or damage inside the tire, even when the tread looks fine (Michelin).
• After a hard hit. Bridgestone advises having the tire taken off the wheel and inspected after you strike something in the road, because damage may not show (Bridgestone).

Nails and screws: repair or replace?

Many punctures can be fixed properly. The U.S. Tire Manufacturers Association's guidance (USTMA tire repair basics; USTMA repair chart):

• Repairs are limited to the tread area. Damage that reaches the shoulder, or that runs at an angle into it, should not be repaired. Sidewall punctures aren't repairable.
• The hole can be no larger than 1/4" (6 mm).
• The tire has to come off the wheel so the inside can be inspected. A proper repair fills the hole with a rubber stem (plug) and seals the inner liner with a patch. A plug alone is not a proper repair.
• Never repair a tire worn to 2/32", or one with an earlier improper repair.

Some tires, including some run-flats and speed-rated tires, have their own repair rules from the maker, so ask the shop.

So how often should tires be replaced?

There isn't one honest mileage number. How long tires last depends on the tire, the car, how and where you drive, and how they're looked after. The reliable approach is to check them monthly, which NHTSA suggests doing when you check your tire pressure (NHTSA), and replace them when any of the signs above show up. If your vehicle maker recommends rotation, NHTSA's general range is every 5,000 to 8,000 miles, which helps tires wear evenly.

Replacing one or two instead of four

• All-wheel drive: many AWD systems are sensitive to tires of different diameters. Tire Rack's guideline is to keep all four within 2/32" of tread depth (or 1/4" in circumference), and it lists different limits from some vehicle makers (Tire Rack). Consumer Reports notes that one new tire can be shaved to match the others (Consumer Reports). Check your owner's manual first.
• Two new tires: Tire Rack's policy is to put the two new tires on the rear axle, which lowers the chance of losing control if the tires hydroplane (Tire Rack). Costco's tire centers follow the same practice (Costco tire center FAQ).

If you do need tires

Don't put off a needed replacement to wait for a deal. If you have some time, though, our current tire rebates table lists this month's brand offers with their deadlines. If you're thinking of buying online, read how ship-to-installer buying works. For winter driving, see all-season vs. all-weather vs. winter tires and our winter tire rebates page.

This guide is general information, not a substitute for an inspection by a tire professional.

Common questions

What is the minimum legal tread depth?

In most U.S. states it is 2/32 of an inch. NHTSA says tires should be replaced when the tread wears to 2/32 inch. A few states differ, so check your state's rule.

How do I read the date on my tires?

Find the tire identification number starting with DOT on the sidewall. Its last four digits are the week and year it was made: 2419 means the 24th week of 2019. Tires made before 2000 use three digits.

Do tires expire if they aren't used?

Tires age even in storage or with little driving. Michelin and Bridgestone recommend replacing tires 10 years after manufacture, including spares, and having them inspected by a professional after five years of use (Michelin says yearly). Some vehicle makers recommend replacing them sooner.

Can a tire with a nail in it be repaired?

Often, if the puncture is in the main tread area, no larger than 1/4 inch (6 mm), and repaired from inside the tire with a plug and patch. Punctures in or near the shoulder or sidewall should not be repaired, per USTMA guidance.