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Underinflation is the number one enemy of a
tire. Operating an underinflated or overloaded tire
at highway speeds on a warm summer day is a recipe
for tire failure.
Be
sure to measure the inflation pressure of your
tires, including your spare, at least once a month.
While doing so, take a moment to ensure that the
tire is securely fastened to the vehicle.
Don’t
overload your vehicle.
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Warning:
Avoid driving on a seriously
underinflated tire for your own safety and
to prevent damage to the tire. |
Be sure to add air to
your tires during the winter months. Make certain
that both the air pump hose valve and the tire valve
are free of snow and other debris that could cause a
leak in the tire valve. Don’t forget to put the cap
back on the tire valve when you’re done. |
Inflating your
tires
The tire and rim assembly is an air chamber
that, when inflated to the proper pressure,
supports the weight of the vehicle. Since the
air pressure supports 95% of the weight,
inflation is a critical part of a tire’s ability
to perform.
You can’t tell if your tires have enough air
just by looking at them. Even though they may
look fine, they may be underinflated by as much
as 20%. According to a recent study, about 70%
of the vehicles on the road in Canada have at
least one tire that is either over or
underinflated by more than 10%. In fact, 23% of
all vehicles surveyed had at least one tire
underinflated by 20%. This represents a real
safety issue.
Underinflation increases rolling resistance,
which reduces tread life and increases fuel
consumption. It can also lead to sudden tire
failure. Without enough air, the sides of a tire
bend and flex too much. This builds up heat,
which can cause serious damage. Operating a
vehicle with just one tire underinflated by 56
kPa (8 psi) can reduce the life of the tire by
15,000 km and can increase the vehicle’s fuel
consumption by 4%.
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Find the
vehicle manufacturer’s recommended pressures
for your front, rear and spare tires. The
recommended pressures are printed on the
vehicle’s tire information label, which is
usually attached to the edge of the driver’s
door, the door post, the glove box or the
fuel door. If you can’t find the label,
check your owner’s manual.
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Use a
good-quality gauge to measure the pressure
of each tire. The pocket gauges sold by
automotive supply stores are generally more
accurate than those on gas station air
pumps.
-
Measure the
pressure when your tires are cold, and don’t
forget the spare. Tires will be cold if the
vehicle has been stationary for at least
three hours or has not been driven more than
2 km.
-
Remember that
tires lose pressure when the air temperature
gets colder (about 7 kPa or 1 psi for every
5°C drop in temperature). Tires may also
lose a certain amount of pressure due to
their permeability (about 14 kPa or 2 psi
per month).
-
Overinflation
can be a problem too. An overinflated tire
rides on just the centre portion of the
tread. The smaller contact area means
reduced grip on the road, leading to a harsh
ride, handling issues (such as steering and
stopping problems) and increased wear on
tires and suspension components.
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