Things You'll Need:
- Tire Pressure Gauge
- Air Compressor
- or a Gas Station
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Step 1
First you need to know what your tire pressure should be. Don't rely on what someone says, most people aren't mechanics. On the side of the tire it will somewhere tell you the maximum pressure. Look for "MAX PRESSURE ##PSI or ###KPA". PSI is the US pressure standard. Most car tires will have a maximum pressure of 35 or 44PSI. Truck tires often are up to 80PSI. So now you know the MOST pressure the tire can hold.
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Step 2
Subtract 10% from the MAX PRESSURE to get the reccommended pressure. This is to compensate for tire heat while driving, so the pressure does not go over the MAX pressure. So for 44PSI you should have 40PSI in the tire, 35PSI about 32, etc.
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Step 3
Now you need to find out what the pressure in your tire is right now. Tire pressure gauges are cheap, or most gas stations that have an air compressor outside to fill your tires have one you can borrow. Unscrew the little black cap on the tube sticking out of your tire and stick the gauge on it. Don't use a ton of force, just adjust it to make sure there is no air hissing out as this will throw off the reading. A bar will slide out of the gauge with a bunch of numbers on it. To read the tire pressure, just find the lowest number you can read on the bar.
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Step 4
If the pressure is lower than it should be, put the air compressor nozzle on the tire for a few seconds and recheck until it is correct. If it is too high, put less force on the gauge so it leaks some air and recheck until it is correct.
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Step 5
Repeat for the other 3 tires and you're all set! Using this method you will get the best mileage, both in miles per gallon and tire mileage (how long your tires last).
