Treading Softly Where the Rubber Meets the Road
Caring for Your Tires
by Jim Bray
It could be time to think about retiring.
Retiring your car, of course. Your "nest egg" notwithstanding, its
important to know when your vehicles rubber has been rubbed out. Your
tires, after all, form the all-important bond between the tons of metal and
material that you drive and the asphalt on which you drive it.
But its an asphalt jungle out there, with terms like Z
rated, 60 series, Run Flat, and others
- as well as conflicting data that tells us bald tires are unsafe, while
racers use them all the time.
Talk about a tiring subject!
Tires are surprisingly complex beasties. They start with a rubber-coated steel
loop, the Bead Bundle, that keeps the tire seated on the wheel rim. The Body
consists of fabric plies(layers), which in a radial tire run at
90 degrees to the tread. Belts, as in steel belted provide puncture
resistance and help the tread stay as flat on the road as possible. The Sidewall,
the part you see when you admire a nice set of wheels, protects the body and
provides sideways stability so your vehicle doesnt flop over the first
time you hit a tight corner.
Then theres the tread, but before its added, the pieces are assembled
into a green tire and then everythings bonded together (called Vulcanizing)
while the tread pattern and that fancy side lettering are molded in.
Presto! A brand new tire!
Different tread patterns offer maximum traction, depending on the tire, for
pavement, dirt, mud and snow, rain, etc. Choosing which tires best for
your vehicle depends on what you drive and where you drive it. You have
to make some compromises, says Scott Wilson, Manager of Advocacy and
Community Services for the Alberta Motor Association. If you do a lot
of city driving, with only occasional highway driving, you can probably get
away with a good all season tire, but in rural areas you might need an actual
snow tire for the winter. You can even take it so far as to look at some specialized
Wilson warns about tradeoffs, however. All season tires work pretty
well, but a good snow tire is actually much better for winter driving. You
have to keep in mind, though, that if you keep (winter tires) on in the summer
your vehicle wont handle as well or ride as smoothly, and itll
be a lot noisier. Summer-driven winter tires also wear much more quickly,
Besides garden variety all season tires there are also All Season
M&S (mud and snow) tires, Light Truck & SUV Off-Road, All-Terrain Tires
- and variations.
Run Flat tires allow you to drive for a short distance even if the tire deflates,
while temporary spares, as the name screams out, Are only meant to get
you to the nearest garage, says Wilson.
Choosing the correct rubber for your lifestyle also means taking into account
tire size and configuration. This is where those numbers and letters on the
sidewall come in (see below), and its important
to match the tire to the vehicle.
Buying tires is only the first step: you also need to take care of them which,
according to the AMAs Wilson, isnt a priority with many drivers. Most
people dont even check their tires
pressure, he says, pointing out that all your tires - including the spare
- should be checked once a month, while the tires are cold. Wilson recommends
buying an inexpensive tire gauge, which he says are far more accurate than
the ones at the local garage, and to keep it in the car at all times.
According to Doug Paulgaard, owner/manager of Fountain Tire in High River,
tires should be rotated Every 8-10,000 km to help ensure even tread wear. His
advice is to have the tires inspected during rotation, and to ensure theres
enough tread left. If theres only 2/32 inch of rubber left, he
says, A wear indicator shows a solid bar across the tread. If you see
that, its time to replace the tire.
Which begs the question Why do race cars use bald tires?
Rick Coutts, Chief Driving Instructor for the Western Canada Motorsports Association,
says It comes down to optimizing grip, which depends on two things: the
load pressing the tire into the track, and the surface area of the rubber contacting
the pavement. The racing slick, Coutts says, has more rubber touching
the road than a similarly-sized treaded tire. Since racers are concerned
with the maximum possible grip a slick tire is the tire of choice.
This changes once theres significant water on the track, however, which
is why racers switch to treaded tires - or quit racing altogether - when it
So treaded tires are actually a compromise between ultimate
stick and being able to control the vehicle in the real world,
where you have to deal with changing weather conditions.
Besides rotating the tires at 8-10,000 km intervals, you should have them
rotated at the first sign of irregular wear. Tires should also be balanced
to minimize vibration and avoid steering and suspension damage. And proper
alignment ensures the tires are actually heading where you want them to, so
avoid scuffing against curbs because that can throw out your wheels
Visually inspect your tires frequently, and remove stones, glass and other
stuff from the tread to prevent damage and/or leaks.
As the slogan says, theres a lot riding on your tires, so making sure
yours are properly maintained is absolutely vital when the rubber meets the
P225/50 R 16 92 V
P indicates a passenger vehicle tire (LT = Light Truck
and T = temporary). The next number (225) is the width in millimeters
from sidewall to sidewall. Then comes the aspect ratio (50), the
height from the bead to the top of the tread, as a percentage of the width
(a 50 series tire is half as tall as it is wide: the lower the number, the lower
profile the tire).
Next comes tire construction: R means radial, todays most
common. Then comes the wheel rim size (16), in inches. Load Rating (92) indicates
how much weight the tire can safely carry; the higher the number the greater
The Speed Rating (V), tells you how much of an accelerating experience you
can expect. Maximums range from a low of 50 km/h (B rating) to
a high (Y) of 300 km/h.
So our P225/50 R 16 92 V tire is a passenger vehicle radial tire thats
225 mm wide, half as tall, fits 16 inch rims, can carry up to 630 kilograms
and (if you can get away with it), is safe up to 240 km/h (the tire, not necessarily
the driver or vehicle!).
Not all manufacturers include the tire type on the vehicle, but
your dealer can help if you arent sure.
There are other indicators as well, for example the Uniform Tire Quality
Grade System but you dont need to be as up on that particular knowledge
unless youre really doing your homework.