When to replace your tires

Tires do not usually fail all at once; they wear down, and the question is when the remaining tread stops being enough. Here is how to check it yourself before you decide.

The legal minimum is not the safe minimum

Bridgestone says the U.S. Department of Transportation recommends replacement at 2/32 of an inch, "and many states legally require tires to be replaced at this depth". Do not wait for that mark in a wet climate: Bridgestone calls 4/32 of an inch "a depth that's vital for safe stopping in wet weather", because below it wet stopping distances grow and the hydroplaning risk rises. Plan new tires at 4/32. Source: Bridgestone, "How to Check Tire Tread Depth: The Penny Test", read 2026-09-17.

The penny test

Insert a penny into your tire's main tread groove with Lincoln's head pointing down into the groove. If you can see all of Lincoln's head, your tread is at or below 2/32 inch, the legal minimum, and replacement is due. If part of his head is covered, you have more tread than that, though you may still be below the safer 4/32 threshold. Check at several points around each tire, not just one spot, since wear is not always even.

Built-in wear bars

Every modern tire also has small raised rubber bars molded across the tread grooves at the 2/32 inch depth. When the tread around them wears down flush with these bars, that is the manufacturer's own built-in signal that you have reached the legal minimum, without needing a penny or a gauge.

Signs beyond tread depth

• Uneven wear across the tire's width can point to an alignment, suspension, or inflation problem rather than just age; replacing the tire without fixing the cause means the new one wears the same way.
• Cracking in the sidewall (dry rot) happens as rubber ages, even on tires with plenty of tread left, and can be a replacement reason on its own.
• Bulges or bubbles in the sidewall mean internal structural damage and call for replacement, not a repair.
• A tire's age, found in the DOT code on the sidewall as a four-digit week-and-year stamp, matters separately from tread; rubber degrades over years even with light use.

How this connects to two-versus-four tires

If only some of your tires have reached these thresholds, whether you can replace just those or need to do all four often comes down to your drivetrain. See Replace two tires or four? for that decision, especially if your vehicle is all-wheel or four-wheel drive.

What we do not do

We do not repair tires, so if your tread is fine but you have a puncture, see Repair vs. replace a tire instead of requesting us.

Questions people ask {#faq}

• How often should I check my tread? A quick check every month or two, and before any long trip, is enough to catch this before it becomes urgent.
• Do all four tires wear at the same rate? Not always; front and rear tires often wear differently depending on your drivetrain and driving style.
• Is a tire with good tread but visible cracking still safe? Cracking is an age and rubber-condition issue separate from tread depth; if it is significant, replacement is the safer call regardless of tread remaining.
• Can you check my tread depth without me buying tires? Yes, the technician can note it as part of any visit, including a seasonal changeover.

Why book this way

• Your price online in minutes. No callback, no estimate visit, no waiting for someone to get back to you. Typically the quickest way to book this service.
• One all-in price before any contact. Of the national mobile tire services we read, only Tire Rack publishes an installation price; the others quote after you contact them or reach checkout (read 2026-09-16 and 2026-09-17).
• One point of contact from your request to the finished job. We work with a local partner and answer for the result.
• You pay only after the price and your booking are confirmed.

Get my price

If your tires are at or near these thresholds, request a replacement and we will confirm a price before you commit. Checkout is a labeled preview until card payments are enabled.

Sources

• Bridgestone, "How to Check Tire Tread Depth: The Penny Test," https://tires.bridgestone.com/en-us/learn/automotive/tire-maintenance/how-to-check-your-tire-tread-penny-test, accessed 2026-09-17.