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Learn2 Improve Your Gas Mileage (continued)
Step 1: Maintain optimum tire pressure

It sounds like a no-brainer, but when was the last time that you checked your tire pressure? It takes more effort for an engine to propel an underinflated tire than a properly inflated one--the engine uses more gas to move it along.

The trickiest part of checking your tire pressure is that you actually have to check it twice: once before the vehicle has been moved that day, and again when you're at a gas station with an air hose. The first reading is from a cold tire, and it's the accurate one, while the second is from a tire that has warmed up from rolling on the pavement. Here's the routine:

  • Get a good quality tire gauge, and measure the pressure in all four tires before you move the vehicle. You'll do this by removing the plastic caps on your valve stems and pressing the gauge firmly down over the metal threads on the end of the stem. You'll hear a little hiss as a bit of air escapes, but when you press the gauge firmly down and hold it there, the noise will stop and the gauge will register the tire pressure.

  • Write down the measurement for each tire--this is your coldmeasurement. Tire companies specifications reflect cold tire pressures, and pressure is measured in PSI, or Pounds per Square Inch.

  • The auto manufacturer has specified tire pressures for both front and back tires. Look for these specs on the inside edge of the driver's door, on the inside of the glove compartment door, or in the owner's manual.

  • Compare the cold measurements with the manufacturer's pressure recommendations. If the manufacturer recommends a different pressure (either higher or lower) than the cold measurement, you'll adjust the tire pressure accordingly.

  • Find a service station with an air hose. There will either be a metal handle that releases air when you squeeze it, or a simple metal fitting that releases air when it's pressed over the valve stem.

  • Take the tire pressure again with your own tire gauge. It'll probably be a bit higher than the cold measurement, since the tire has warmed up from rolling along the pavement. This will be the warm measurement.

  • If the cold measurement was lower than the manufacturer's recommendation, add the proper amount of air with the hose.

  • On the other hand, if the cold measurement was higher than the manufacturer's recommendation, release the excess pressure from the tire. (This is easy to do: find the valve, and press on the metal piece in the center of the valve with your fingernail, a key, or a small stone, until your hear a hissing sound.
  • Overly inflated tires can wear unevenly, so don't try to overinflate them into balloons.

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Step 1: Maintain optimum tire pressure
Step 2: Keep it in tune
Step 3: Change your driving habits a little


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