AAA's guide to maintaining your tires

Maintaining your tires is an unavoidable part of car ownership. Tires affect many other aspects of driving, including fuel economy, handling, braking, comfort, and weather safety. That's why proper tire care is essential: Neglecting it can reduce your tires' useful lifespan, lead to expensive problems, and make your car more dangerous to drive.
How to recognize irregular tire wear
Depending on how old your tires are and what stresses they’ve been subjected to, their wear may be subtle, or impossible to miss. An inspection of each tire’s tread is a good place to begin. A properly maintained tire will show even wear all over; any other pattern is a good indicator that something is wrong with the tire pressure, suspension, or wheel alignment.

Under & overinflation

Underinflation: Too little air in a tire causes the center to sag inward and experience less contact with the road, leading the edges of the tread to wear down more quickly.

 

Overinflation: Too much air in a tire causes the center of the tread to bulge outward, where it bears the brunt of road contact and wears down more quickly.

Suspension issues

Misaligned wheels: A misaligned wheel focuses friction on one side of the tire, leading it to wear down more quickly.

 

Wheel balance/suspension: Worn-out suspension parts (usually shocks or struts) or wheel-balance issues allow a tire to bounce in and out of contact with the road, creating "scalloped" grooves.

Issues while driving

Vibrating, humming, or thumping: Such noises can indicate cupping, flat spots on a tire, out-of-balance wheels, or a tire with a separated internal belt.

Pulling to one side: If the car pulls to one side while driving at a steady speed, there may be an underinflated or damaged tire on the side it pulls toward.

Tire rotation

Front tires and rear tires handle different amounts of acceleration, steering, and braking wear. For example, the front tires on front-wheel drive cars absorb the brunt of both acceleration and braking, so to prevent the front tires from wearing out long before the rear tires, the front tires must periodically be swapped to the back and the rear tires to the front. (The exact way the tires are rotated usually depends on whether the vehicle is front-, rear-, or all-wheel drive.)

 

Check your vehicle’s owner’s manual for mileage recommendations; rotation is usually recommended between every 5,000 and 8,000 miles.

How to measure your tread depth

Tires depend on grooves in their treads to maintain traction and shed water on wet roads. Depth is measured in 32nds of an inch, with most new tires starting out at 10/32” or 11/32”. Measuring your remaining tread depth is one of the most important car inspections you can do; you should do it monthly to uncover excessive or uneven wear before it becomes a safety hazard. 

The easiest and most accurate way to check tread depth is with a dedicated tread depth gauge, available at auto parts stores. But if you have some spare change handy, you can also use a quarter or penny to measure depth.

coin test

In many states, it’s illegal to drive on tires with less than 2/32” of tread, so seeing the top of Lincoln’s head means your tires need immediate replacement, but even tires that pass the penny test may be worth replacing.

The Tire Rack, America’s largest independent tire tester, found significant performance differences between tires that only passed the penny test and those that passed the quarter test as well. In one test, pickups traveling at 70 mph that only passed the penny test needed 499 feet to stop on wet pavement, while pickups that passed the quarter test needed only 377 feet, a 24 percent improvement. Given these results and others, AAA suggests using the quarter test to determine when it’s time for new tires.

How to inflate your tires properly

 

Having the wrong tire pressure leads to uneven wear and lower gas mileage, so you should check your car’s tire pressure at least once a month to make sure it’s at the manufacturer-specified level.

 

1. If you don’t already have one, get a tire pressure gauge. There are digital, dial, and pen-type varieties, with the digital and dial models generally being easier to use.

 

2. Check the tires before the vehicle has been driven. Warm tires will give higher readings than tires at rest.

 

3. Remove the tire’s valve cap, press the gauge over the valve stem, and press firmly until there’s no air hissing out.

 

4. Note the tire's current pressure on the gauge. Compare it to the pressure specified by the manufacturer, usually found in the owner's manual or in the driver's door jamb.

 

5. If the pressure is below normal, add air, rechecking with the gauge that way you don't add too much.

 

6. If the pressure is above normal, or you overfill the tire, release air by pushing on the metal stem in the middle of the valve with a fingernail or pen.

 

7. Replace the valve cap and repeat for the other tires. If your vehicle has a spare tire, check it as well. Keep in mind that some spares require higher inflation pressure.

Tire maintenance checklist

 

Every month, you should:

 

  • Examine tire treads for signs of irregular wear
  • Check tread depth with a depth gauge, quarter, or penny
  • Check tire pressure, refilling if necessary

 

Every 5,000 to 8,000 miles:

 

  • Have tires rotated to spread wear evenly

 

When you get new tires:

 

  • Have wheel alignment checked and new tires balanced
Need an inspection, rotation, or new tires?
If you'd rather have a professional take a look at your tires, or you need more work done than you can do yourself, consider a AAA Approved Auto Repair shop. These shops are regularly inspected by AAA and come with member benefits.
You love your car; AAA loves keeping it running
Through November 30, 2018, AAA members can take advantage of the AAA Car Care Service Package1, starting at $34.99 with conventional oil (additional cost for synthetic oils). The package includes: oil and filter change, tire rotation (if needed) and 40-point vehicle inspection, including battery test. Available at participating AAA Approved Auto Repair facilities. 

1AAA Car Care Service Package is a limited-time offer for members, valid 8/20/18-11/30/18, priced at $34.99 with conventional oil, $54.99 with synthetic blend oil, or $74.99 with full synthetic oil. Oil change includes up to­ five quarts of oil. Tire rotation is only performed if needed. Tax and environmental fees not included. Available for most passenger cars and light trucks. Diesel and select domestic, European, Asian and exotic cars excluded. Inspection is limited to items identi­fied on the designated inspection form only. Cost of any repairs not included. Appointment may be required. Contact the facility in advance for details. Other restrictions may apply. Not valid with any other offer, including 10% AAA member discount. Valid AAA membership card must be presented at a participating AAA Approved Auto Repair facility at the time of service.

 

Information from "Tire Safety and Maintenance," American Automobile Association's AAA Exchange, Copyright © 2013, and "Be Tire Smart, Play Your Part" brochure, Rubber Manufacturers Association, Copyright © 2006.