Experts agree that keeping the correct air pressure in your tires is as
important as giving your engine a tune-up. In fact, the economic benefits
may be even greater. With the right amount of air pressure, your tires
wear longer, save fuel, enhance handling, and prevent accidents. Failure
to maintain the correct air pressure can result in poor gas mileage, loss
of tire life, bad handling, possible loss of control, and potential
vehicle overloading. If you consider these liabilities, then the need to
routinely add air to your tires will become even clearer.
Because tires do so much without appearing to need attention,
it's easy to forget about them. However, tires do lose pressure
each day, through the process of permeation. In cool weather, a
tire will typically lose one or two pounds of air per month. In
warm weather, it's common for tires to lose air at an even higher
rate. Tires are also often subjected to flexing and impacts that
can diminish air pressure as well. So it's important to realize
that refilling your tires is as important as refilling your gas
tank. In fact, associating the need to refill your tires with the
need for refilling your fuel supply can also be a useful reminder.
Check the air pressure in your tires every other time you stop to
fill up at the gas station. That interval will allow you to check
your tire pressure consistently enough to maintain recommended air
pressure. Another good time to check air pressure is when the
tires are rotated. Many vehicles have different tire pressures on
the front and rear axle, so remember to have this adjustment made.
Also remember to have the pressure in your spare tire checked. The
space-saver type spare requires a much higher air pressure level
than other tires, and is virtually useless (due to overloading) at
lower air pressure levels.
The correct air pressure may be found in the vehicle owner's manual or on
the tire placard (attached to the vehicle door edge, doorpost, glove box
door or fuel door). The placard tells you the maximum vehicle load, the
cold tire pressures and the tire size recommended by the vehicle
manufacturer. If you have trouble, visit
your local Discount Tire
or America's Tire location for assistance.
Another valuable resource is tire load/inflation tables. Your local Discount
Tire/America's Tire should have a copy. Not only will this document tell you
the correct tire pressure for stock sizes, but it will provide the
information on optional plus sizes as well. A good example would be the
findings on a Honda Civic with the stock size 185/65R-14. The recommended
air pressure is 28 psi. Plus one size is 195/55R-15 with a recommended air
pressure of 32 psi. Plus two size is 205/45R-16 with a recommended air
pressure of 36 psi. Note how the air pressure increases with plus sizing to
meet the load carrying capacity for the car.
In addition to routine air checks, other circumstances necessitate a
visit to the air pump. Seasonal changes or altitude changes create a
rise or drop in air pressure (for every 10 degrees change in
temperature, tire air pressure changes 1 psi). Perhaps the most
overlooked factor is vehicle loading for trucks and RVs. Since these
vehicles can be configured and loaded in many ways, actual tire loads
should be used to determine the proper inflation pressure. This is
best determined by weighing the vehicle. Keep in mind that vehicle
loading can change from trip to trip.
One of the most dangerous conditions that can occur is the slow leak. Sometimes
a small nail, screw or other object will puncture a tire and then act as an
inefficient plug. Air pressure drops slowly over a matter of hours or days,
undetected by the driver. Your best defense in this circumstance is to be alert
to the symptoms of this. Be aware of any pulling or vibration that seems
unnatural. Listen for any ticking sounds, which will be especially audible at
slow, parking lot speeds. If you detect this, get off the road and inspect the
tires on the side of your vehicle where the pull, vibration or unusual sound is
occurring. A bulging sidewall and/or excessively hot tire indicates a slow leak.
Put on your spare tire and have your tire dealer repair the punctured unit. Ask
the repair technician if any sidewall damage has occurred (a powdery residue
inside the tire indicates this condition). If sidewall damage has occurred, you
will need to have the tire replaced.
Properly checking tire pressure requires an accurate air gauge. Many people
believe that they can check air pressure just by looking at the tire and
judging the sidewall appearance. Also, many people use air meters at service
stations, which can be grossly inaccurate due to exposure or abuse. Invest
in a quality air gauge. For trucks and RVs, use a dual-head inflation gauge
that is calibrated up to 120 psi at 2 psi increments.
When checking your vehicle's tire pressure, make sure the tires are "cold".
Cold air pressure means that the vehicle has not yet been driven one mile.
Remember that driving on a tire increases its temperature and air pressure.
If you must drive more than one mile for air, check and record the air
pressure in all your tires before you leave. Once at the tire dealer, measure
each tire's inflation again and then note the difference. Inflate the tires
with low pressure to a level that is equal to the recommended cold pressure
plus the difference at the higher temperature.
Finally, after completing the pressure check, make sure that the valves and
extensions are equipped with valve caps to keep out dirt and moisture. Remember
to replace the valve assembly when you replace the tire. It's your best
assurance against a sudden or consistent loss of air pressure.
How can routine air pressure maintenance impact our environment? Consider that
fewer tires per year would end up in the landfills and scrap heaps that trouble
our ecology. How many tires are we talking about? We estimate that most drivers
lose from 10% to as much as 50% of tire tread life due to underinflation.
That's a significant statistic. Now consider the extra fuel we burn to push cars
along on soft, underinflated tires. Tires do require extra energy to roll if
they are underinflated. While the statistics vary widely and can be somewhat
inconclusive, the implications are staggering. Maintaining tire pressure may
seem like a low priority in our busy daily routines, but it adds up to big
environmental consequences. We must all take action to do the right thing.
Want to know more about better tire wear? See our articles on Balancing,
Tire Rotation, and Alignment. |
