New Tires/ Tire Rotation
• Explain how the owner can
quickly check the tires (using the coin in the tread trick).
Got a Lincoln penny? Chances are you do, since the U.S. Mint has
been cranking these out since 1909. Because a simple Lincoln head penny
is the perfect size, using one will make it easy to determine when to
buy new tires.
It only takes a few steps to check your tire
depth:
Pinch a Lincoln-head penny, from the base, between your
thumb and forefinger, so that the top of Lincoln's head and the words
"In God We Trust" are showing.
Place the top of Lincoln's head
into one of the tire tread grooves -- try to measure in the lowest point
within the tread.
What is tread?
All tires have what are
called "tread wear bars". These are small bridges that form between your
treads. Look at the tread pattern and you will see the beginnings of
these bars start to form between the treads, or running across the
tires. As the tires wear, these bars will become flush with the tire's
tread. At this point it is time to replace the tires
If
you see uneven wear on a front tire, chances are that the front end is
out of alignment. You should have this checked and rotate the tires to
the rear if possible (some vehicles have different sizes on front than
the rear). The tires from the back should be fine and the uneven tires
moved to the rear will start to correct themselves. Tires do not wear
perfectly evenly, so be sure to insert the coin at several points from
the outside to the inside of your tires. Tires generally wear more on
the inside but over-inflated tires will wear more in the middle.
• Explain tire rotation, what it does and how often the owner should
rotate their tires.
How To
Rotate Your Tires
By Scott Memmer
Email
Tire rotation is an important
maintenance duty that extends the life of your tires and ensures safe
driving. We'll take a look at this simple but effective procedure.
Whether
you plan on doing the job yourself or having it performed by a
certified mechanic, it's important to know why we rotate our tires.
Front
And Rear Tires Wear Differently
Think about it. All that
parallel parking. All those three-point turns. With each turn of the
steering wheel, pressure is brought to bear on the front tires. (This is
even more accentuated in front-wheel-drive cars, where the front wheels
also supply the main motive power for the vehicle.) Resistance causes
friction, which in turn produces heat. The result? The front tires wear
quicker than the rears.
Because of this, it's necessary to
rotate the tires front-to-rear several times during their life cycle to
1) equalize tread wear and 2) maximize the life of the tires. This is
what we refer to when we say "rotate the tires."
Rotating
generally does not refer to either of the following actions:
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Exchanging
tires on the same axle — for example, swapping the rear tires left to
right
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Criss-crossing tires — moving a tire from the
passenger's side rear to the driver's side front
There's
a good reason for this. Tires develop wear patterns as they age. Some
of these patterns are tied to the suspension system and the alignment.
That's why we keep the tires on the same side of the car.
If
your car has staggered wheels -- the front and rear tires are two
different sizes, such as with the Chrysler Crossfire -- you can still swap the tires
side-to-side, but not front to back. If your tires are unidirectional
(specific to one side of the car) or asymmetrical (the tread pattern
changes from the inside of the tire to the outside), you can rotate them
front to back but not side to side. And if you happen to have staggered
wheels that are also unidirectional or asymmetrical, you cannot rotate
your tires at all! But that's rarely the case.
How often should
you rotate your tires? That depends. Refer to your owner's manual for
exact guidelines, but most manufacturers recommend rotating tires
roughly every 5,000 to 10,000 miles. Again, see your owner's manual for
specifics.
An important tool needed for this procedure is a
torque wrench. They range in price, but you can get a simple one for
under $35. The torque wrench is especially necessary on modern cars with
alloy wheels, to avoid over tightening and damage to the wheels. The
recommended torque specs can be found in your owner's manual or online.
With that knowledge, let's move to
the procedure, provided your car has four wheels with equal tire sizes
and matching tread patterns.
Ready To Rotate Your Tires?
Park
your car on level pavement. Put the car in "Park" (or in gear, if it's a
manual transmission) and set the parking brake firmly. Turn off
the engine.
Choose which side of the car that you want to work
on first. Now go to the opposite side and block the tires, front and
rear. This is a precaution and will prevent the car from moving while
you work on it.
There are several kinds of jacks you can use to
elevate the car. The most readily available may be the jack that came
with the vehicle. However, this is also the most unsafe and should only
be used for short periods of time. If you use this jack, we recommend
safeguarding yourself by using jack stands under both the front and rear
axles. In fact, this isn't a bad idea anytime you're working around an
elevated vehicle. Once the car is in the air, position the jack stands
under the axle, behind each wheel; then gently lower the weight of the
vehicle onto the jack stands.
You can also use a small hydraulic
jack or -- the best of all possible options -- a floor jack. Whatever,
the principle is the same. Locate a point under the frame nearest the
manufacturer's recommended jacking point, and position the jack there.
In most front-engine vehicles, this will be a foot or two behind the
front wheel. (There will sometimes be a hole facing you here, where you
can insert the extension from the jack.)
Before you elevate the
vehicle, you will want to take the lug wrench and loosen the lug nuts on
both the front and rear wheels. This technique uses the vehicle's
weight to hold the wheels in place, so they don't spin as you crank on
the lug nuts.
Once the lug nuts are loose, jack up the vehicle
and then, if you have jack stands, back down onto the stands. Spin off
the lug nuts and put them in a safe place.
Remove the front
tire, then the rear, and switch their positions, rolling the front tire
to the rear, and the rear to the front.
Before you mount them,
let's inspect the tread.
The tread pattern has wear indicators
built into it. These are little bumps or nubs manufactured directly into
the tread. Inspecting them will tell you how close the tire is to
needing replacement. See if you can spot them. They're located
throughout the tread pattern, but especially on the ridge where the
tread and sidewall meet. Find one? Compare its height to the height of
the tread surrounding it. If the tread is wearing to the point where its
height is approaching that of the wear indicator, you'll need to be
shopping tires soon. Make a mental note.
Now go ahead and mount
the tires, having switched front to rear, etc. If you have a friend
handy, have them hold the tire while you thread the first lug nut or two
into its hole. Once all the nuts are threaded finger-tight, grab the
torque wrench and tighten them further.
Now, as before, you want
to use the weight of the vehicle to hold the wheels in place while you
snug the lug nuts down good and tight. Jack the vehicle up off the jack
stands (if you're using them) and then slowly let it sink to the
ground.
Take the torque wrench and tighten the lug nuts to their
recommended specification.
By the way, it's best to work the
lug nuts diagonally across from one another, as though forming a star,
instead of side to side. This allows them to seat better into their
cradles.
Done. Now go to the other side of the car and repeat
the steps.
That's All There Is To It...
Remember, this
quick and simple procedure will extend the tread life of your tires. It
will also provide maximum gripping power to the vehicle.
To
repeat: this should be done roughly every 5,000 to 10,000 miles. Check
your owner's manual for exact intervals.
You don't need some
fancy mechanic with a lot of expensive tools to do this job for you.
This is one you can do yourself.
• Explain tire
pressure and its importance in handling and gas milage.
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Importance
of Tire Pressure
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Safety
· Low air pressure
causes erratic wear and is the #1 cause of tire failures.
·
Properly inflated tires extend tire casing life, resulting in
less overheating and fewer blowouts.
· Low tire pressure
increases required braking distances and dramatically affects
steering and handling.
· The Society of Automotive
Engineers indicates that 260,000 accidents, resulting in 79
deaths and 10,600 injuries, each year are due to low tire
pressure.
Savings
· The Tire
Maintenance Council reports that tires running 10% under-inflated
lose up to 16% of their tread life.
· Tires
under-inflated by 30% lost up to 10% fuel economy.
· The
average downtime on the highway due to a flat tire is 3-4 hours.
· Roadside repairs costs average $400+.
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