How to Check a Used Tire Before You Buy It

To properly check a used tire, work through four areas in order: tread depth, sidewall condition, manufacture date, and repair history. Skipping any one of them can put a structurally compromised tire on a vehicle, and no reduced sum offsets that risk.

In short: To check a used tire, inspect the tread depth using the penny test or built-in wear bars, look for sidewall bulges or exposed steel belts, decode the four-digit manufacture date on the sidewall, and confirm any puncture repairs were done through the tread only. Reject a tire that shows bulges, cracking, or wear bars flush with the tread.

Gloved hands pressing a tread depth gauge into a tire tread groove on a concrete shop floor

Read the Sidewall First: Size, Date, and What the Codes Mean

Before anything else, read what the sidewall says. The string of characters molded into the rubber tells a buyer almost everything. A typical size code breaks down like this: the first number is the width in millimeters, the next is the aspect ratio (how tall the sidewall is compared with the width, where a higher number means a taller sidewall), R means radial construction, and the final number is the wheel diameter in inches. After those numbers come the load index and the speed rating. The final four digits of the Tire Identification Number stamped on the sidewall show the manufacture date: the first two digits are the week of the year and the last two are the year, so a stamp reading 2910 means the 29th week of 2010.

Age matters on a used tire even when the tread looks fine. AAA reports that hot summers drive higher rates of tire replacements and emergency roadside calls. Check the date stamp before anything else.

How to Check a Used Tire's Tread Depth

USTMA's tire care guidance describes two simple methods. The first is the penny test: place a penny upside down into a tread groove, and if part of Lincoln's head is covered by the tread, the depth is still usable. Once tread wears to 2/32nds of an inch, USTMA says it is time to visit a tire shop. The second method uses the tire itself: every tire has built-in tread wear indicators, called wear bars, molded into the grooves. When the tops of those bars are flush with the surrounding tread, the tire needs to be replaced. On a used tire, check multiple grooves around the full circumference. Uneven wear, high and low areas, or unusually smooth patches are all signs worth flagging, since USTMA notes that misaligned wheels can cause uneven, rapid tread wear.

Tread depth gauge inserted into a tire groove held by a gloved mechanic's hand in a tire shop

USTMA notes that overinflated tires are more likely to be cut, punctured, or damaged when hitting an obstacle such as a pothole.

Used Tire Inspection Checklist

Read the size code and confirm it matches your vehicle's requirement
Find the last four digits of the Tire Identification Number and check the manufacture date
Measure tread depth at the center groove and both shoulders
Inspect the full tread face for uneven wear patterns
Run your hands along the tread shoulders feeling for cracking or brittleness
Look for bulges, bubbles, or deformations across the tread face
Check for any prior repair plugs or patches and assess their placement
Confirm no cords or fabric are visible anywhere on the tread face

Tick items off as you go. This list also prints cleanly.

Sidewall and Structural Inspection

Run a hand slowly around both sidewalls and look carefully at the shoulder area where the tread meets the wall. USTMA's guidance on unsafe used tires is direct: tires with bulges indicate possible internal damage that can lead to tread separation, and tires with damage exposing steel belts or other internal components threaten the tire's structural integrity.

Also look for cracking or checking in the sidewall rubber, which can appear as a network of small surface lines. While minor surface weathering exists on older tires, deep cracking that runs through the rubber signals age-related degradation. In a desert climate, AAA cautions that driving on under-inflated tires causes them to overheat, and this problem becomes even more of a concern when road temperatures are extremely high.

Evaluating Prior Repairs

If a used tire has already been patched, the repair method matters as much as the visible result. USTMA's tire repair guidance is specific: a proper repair requires that the tire be removed from the rim for a full internal inspection, that the puncture injury be no greater than 1/4 inch in diameter, that the damage be limited to the tread area only, and that both a rubber stem plug and a patch be applied. A plug-only repair done without removing the tire does not meet that standard. USTMA also notes that improperly repaired tires can suffer loss of inflation pressure or carry hidden damage. If the seller cannot describe how a repair was done, or if the repair is visible in the sidewall rather than the tread, treat the tire as unsafe.

When sourcing a used tire, also confirm it matches the vehicle's required size, load index, and speed rating. USTMA recommends that replacement tires carry the same size, load index, and speed rating as specified by the vehicle or tire manufacturer, and that if only two tires are replaced, they go on the rear axle.

Where to Find Used Tires in Las Vegas

ABC Tires & Auto Repair, on East Charleston in Las Vegas, carries new and used tires in a wide range of brands for cars, SUVs, pickups, trucks, trailers, and commercial vehicles. Calling ahead with the tire size printed on the current sidewall lets the team check what is in stock before a driver makes the trip. The shop is open Monday through Friday, 8:00 AM to 5:30 PM, and walk-ins are welcome. Spanish is spoken. Reach the shop at (702) 432-6371.

The ASE-certified mechanics at the shop can also mount and balance any tire selected, inspect it on the rim, and check inflation to the vehicle manufacturer's specification, since USTMA notes that underinflated tires generate excessive heat and internal damage. For drivers who want to browse the full tire inventory for cars, trucks, and equipment, a call with the tire size code is the place to start.

A Simple Inspection Checklist

Before any used tire goes on a vehicle, work through this list. Check the manufacture date in the Tire Identification Number on the sidewall. Apply the penny test across multiple tread grooves, and look for the built-in wear bars flush with the tread surface. Run both hands around the full sidewall watching for bulges, exposed cords, or deep cracking. Confirm that any prior repair was done through the tread only, with the tire removed from the rim, and with both a plug and a patch. Verify the size, load index, and speed rating match the vehicle's specification. A tire that clears every item on this list is a candidate worth mounting. One that fails any single item is not.

Taking a few minutes to check a used tire with care before purchase is exactly the kind of inspection that prevents a roadside emergency later. When in doubt, bring the tire to a shop where a technician can inspect it properly rather than relying on a visual check alone.

Common Questions

Does a used tire need to be balanced after it is mounted?

Yes. USTMA recommends having tire balance checked periodically alongside alignment.

How do I find the correct tire size if the sidewall is too worn to read?

If the sidewall markings are unreadable, the tire size appears on a sticker inside the driver's door jamb and in the vehicle owner's manual. The door-jamb placard also lists the recommended inflation pressure. Never guess the size by measuring the tire visually.