Inflating and maintaining proper tire pressure ensures safer, more comfortable driving
and better fuel efficiency. Particularly in times of high gas prices; in inclement
driving conditions such as heavy rain, snow, or ice; and in vehicles of all sizes,
tire pressure can make a major difference in driving, wherever you are.
Given the importance of the task, you might think it is complicated, but checking
and maintaining your tire pressure is simple, provided you have a good tire air
pressure gauge and source of air, both of which are available at many gas stations.
Get a Gauge
A simple tire air pressure gauge, available at most auto parts stores, for a few
dollars, is adequate for the job. You do not necessarily need a digital air pressure
gauge. If it is worth the $14 to $15 to you, a digital pressure gauge is easy to
read and accurate. However, you should consider whether it will require batteries,
and whether this would prevent you from using it.
Again, a standard pressure gauge that measures pounds per square inch (PSI) and
fits easily in the glove box of your vehicle, is sufficient. Do avoid ultra-cheap
models that may not give a proper reading.
As for a source of air, many gas and service stations have air available for 50
cents or so. Some of these air machines have gauges on them, and if you have no
other means of measuring the pressure of your tires, these will work. However, they
are typically beat and inaccurate, so have your own gauge to ensure the proper PSI
for your tires and vehicle.
Checking Pressure
PSI is measured by the notches on a tire air pressure gauge or with a number reading
on digital gauges. To find out what PSI is right for your tires, look on the tires
themselves. In the raised writing on the side of the tires, you should find "recommended
PSI" or "PSI recommended at ..." or similar, with the proper figure for your tires.
Many times this number on the tire is stated as a maximum; you can also consult
your owner's manual or the sticker on the door of the driver's side. When buying
new tires, or getting a rotation, it's a good idea to ask what the ideal pressure
is.
Recommendations may vary, but you should never inflate the tires five PSI more or
less than what is recommended on the tire. Under-inflating wears out the sides of
the tire, and is actually a driving hazard. Over-inflated tires will wear more quickly,
and are also dangerous because of the increased possibility of a blowout. If you
are unsure about the PSI for your tires, or it is unclear or worn away on the side
of your tires, ask your mechanic or someone who knows about vehicles what PSI you
should have for your tires.
Smaller compact and mid-size sedans typically have PSI levels between 30 and 40
PSI. Larger vehicles with larger tires, including bigger sedans, usually have higher
pressure, around 45 PSI. These are general PSI figures, and the most accurate PSI
for your tires is the number listed on the side. Tires should all be inflated to
the same PSI for safety, proper vehicle function, comfort, and fuel efficiency.
Also, check your vehicle's tire pressure when the tires are cold. This means the
tires should not have been driven on for at least three hours. If you need to drive
to get air, try to drive less than a mile. Or, slightly under-inflate the tires
to compensate for the warmer air inside them, and then check the pressure again
when you can get a cold reading.
To get a PSI reading on your tire, place the air pressure gauge onto the tire's
valve stem, the pencil-width air nozzle on the side of the tire. Try to place the
gauge evenly onto the valve stem. This will allow air to escape, but once you firmly
press the gauge down on the valve stem, it will stop the flow of air and give your
gauge a reading, either by blowing out the metered stick with a traditional gauge,
or a reading with a digital model gauge.
Adjusting Tire PSI
So you have a tire pressure gauge, and a source of air. It is best if you can park
your car centered on the source of the air, which usually has a hose to reach the
vehicle's tires. You may need to move the car to reach all of the tires, depending
on the situation. Before you pay any money for air or start pumping up your tires,
remove the caps on all the tire valve stems.
Next, you should check the pressure of all four tires, noting which ones need the
most air. This will help you maintain uniform pressure in the tires, some of which
may need less air. Hot weather, extreme temperatures and other conditions can cause
the air in your tires to expand, and PSI can subsequently increase.
Once you know which tires need more air, you can deposit coins into the air machine,
or get your air hose ready. Choose the first tire to fill, and fit the air hose
nozzle onto the tire stem. When you start to place the air hose onto the tire stem,
it will hit a pin inside the stem and start leaking air. You know when you have
the air hose nozzle properly applied when the leaking air stops. It takes some force
to get the hose locked on, but once it is in place, you will be ready to increase
the tire pressure.
Some air hoses are automatic, and will release air in your tire once you have it
on the tire's valve stem. Other air hoses have handles and require you to squeeze
them to activate the air.
It is important to have your gauge as you fill the tire, taking the hose off somewhat
frequently to check the pressure. It is extremely important not to over-inflate
your tires. You can avoid this by using small bursts of air between your checks.
As you increase the PSI and keep checking it, you will get a feel for how much air
you are putting into the tire, and how much more you need. Once you get close to
your recommended PSI, use less air, and keep going until you are at the right level.
Once you have the tires properly inflated, replace the stem caps by screwing them
back on. Do not over-screw them, as they will break on the top. Tire stem caps are
important to keep your tire valve stems clean and undamaged.
Tire pressure should be checked weekly, or every other week at least. Particularly
with severe weather and temperature swings, tire pressure on the nicest tires with
the nicest cars can still fluctuate, and must be monitored and maintained regularly
for safe and fuel-efficient driving.