En español | It can all begin with the Lincoln test: if you see the top of Abe's head when you place a penny upside down into the tread of a tire, it's time to go tire shopping. The passage of time, or damage and flaking on the sides of the tires, can also signal the need.
It can end up costing a pretty penny — usually $500 to $800 for a set of four.
1. Get the right size. A tire's size is listed on its sidewalls in a sequence such as P265/70R16. Replacement tires should always match what's noted in your owner's manual or car door jamb, not necessarily what's currently on your vehicle.
2. Age matters, even with "new" tires. Tires naturally deteriorate over time, faster in hot climates. A tire's "birthday" is noted as a four-digit number following a letter sequence beginning with DOT, indicating the week and year it was manufactured — 5009, for instance, means the 50th week of 2009.
Vehicle manufacturers recommend you replace tires after six years, no matter what their condition. Since some shops stock old tires, check the age code to make sure you're not being sold ones that are already several years old and well on their way to needing replacement.
3. Learn the lingo. "All-season" tires are a popular and wise choice for most drivers. But think those called "high-performance" or "ultra high-performance" are better? Think again. Tire performance means ability to handle well at higher speeds, not lifespan. Any tire with "high-performance" in its name will likely wear out quicker.
4. Think twice about warranty. Manufacturers often tout mileage warranties — typically between 50,000 to 80,000 miles, depending on tire type. The mechanic whom I use, however, says, "In truth, drivers never get that kind of mileage from their tires. And the heavier the vehicle, the less you should expect — no matter how well you drive."
Before buying based on mileage warranties, know the fine-print details: If tires wear out prematurely, you don't just get a new set for free. There's a prorated credit for replacements, and for that, you'll likely be expected to prove you properly cared for the tires by keeping them inflated to the right pressure, aligned and rotated every 5,000 to 7,500 miles. There may be a careful inspection and demand for service records before warranties are honored.