Maintaining Air Pressure

• The key to keeping your tires performing to the best of their ability is to maintain the correct amount of air pressure. Find the recommended air pressure in your vehicle's owners manual, and often on a placard inside the driver's door frame. Air pressure is measured in pounds per square inch, or PSI.
  
  Perform monthly tire pressure checks using a pressure gauge. It's common for a properly inflated tire to lose one PSI per month, especially during winter months, where cold temperatures cause even faster pressure loss from tires. Tires that are overinflated or underinflated will not perform optimally and will also wear unevenly over time.
  
  Check air pressure when the tires are "cold," meaning before you've driven the vehicle, or three hours after the vehicle has been stopped. When tires are warm, the air inside expands, resulting in a higher pressure reading.
  
  If your tire pressure is low, add air from an air compressor (found at most gas stations), or take it to a nearby tire dealer for a fill-up. It's best to invest in your own gauge, since public ones at gas stations are often old and have been misused, making them unreliable.
  
  Be sure to check your spare tire every now and then, too. This ensures it will be in working condition should you ever need it.
  
  

Checking Valve Stems

• Valve stems, which you use to check tire pressure, are very important to keeping the correct amount of air in a tire. Because they are usually made of rubber, they can deteriorate over time and allow air loss.
  
  Valve caps are also important for containing air, as well as keeping out moisture or other contaminants.
  
  If you find a missing valve cap, replace it as soon as possible. Check the valve stem, which sticks up out of the wheel, to make sure there are no cracks.
  
  

Rotation, Alignment and Balance

• Regular rotation also extends the life of your tires by preventing uneven wear. In a proper rotation, each tire and wheel is removed from your car and replaced in a different position. Check your owners manual for the recommended rotation period. If this is not specified, a good rule of thumb is to get tires rotated every 6,000 to 8,000 miles, according to Michelin.
  
  Alignment is the adjustment of your car's front and rear suspension parts. Accidents, potholes and railroad crossings can affect your vehicle's alignment. Consider getting an alignment if you've hit something in the road, been in an accident, notice a sudden difference in your vehicle's handling or see a tread wear pattern on only the edges of your tires.
  
  Balancing tires prevents one area of the tire/wheel assembly from being heavier or lighter than the rest. This can cause uneven tread wear and vibrations. It also puts added stress on front-end parts like axles and tie rods, causing them to wear prematurely, according to Michelin. Tires need to be balanced when they are new, or if you notice a clip-on weight is missing while performing a check.
  
  

Tread Depth

• In addition to checking for uneven tread wear, it's important to measure your tread depth. Do this using a tread gauge, available at auto parts stores, or a penny. Place the gauge inside a tread groove and read the measurement; if there is 2/32 or less of tread, your tires need to be replaced immediately.
  
  If using a penny, place it upside down in the tread groove (so Lincoln's head is in the groove). If you can see Lincoln's entire head, your tires need replaced. If the tread is still deep enough to hide the top of his head, your tires still have life in them.
  
  

Overall Care and Maintenance

• When performing monthly pressure checks, also look for any cuts, bulges or punctures in your tires' tread or sidewall areas.
  
  Clean tires with a soft brush, soap and water. Be careful when using harsh cleaners and wheel polishers. If overspray gets onto tires, rinse them off with water.