My Car Shakes and Vibrates, What Does This Mean?
Reader Question: My car shakes and vibrates on the
freeway, does this mean I need a front end alignment?
How do you know if your car needs a front end alignment?
Vibrations, shimmy, and shaking felt in the steering wheel are
usually not a sign of needing a front end alignment. A front end
alignment, or four wheel alignment as it is commonly referred to
these days due to the fact that the rear end of the vehicle can
also be adjusted, does just what the name implies align, or line
up the direction of the wheels so the vehicle is pointed in a
straight line.
Caster, camber, and toe are terms used to describe the direction
of the wheel in relation to the body of the vehicle. The front
of the tire can be pointed in toward the center of the vehicle
thus "toed in." When the front of the tire is pointed outward,
it is referred to as "toed out." Both of these problems can
quickly wear down the tread of a tire and can cause a "pull" in
one direction of the front end. The top of the wheel can also
lean in toward the center of the vehicle or lean out away from
the vehicle, causing a camber problem. This situation can also
cause tire wear and a pull to one direction in the front end.
Caster measures the relationship of the left and right wheels to
each other. If one wheel is farther forward or back from the
other wheel, then there is a caster problem. Caster will usually
not cause a pull or tire wear, and this problem is commonly
found on wrecked vehicles.
So what causes shimmy and shakes in the front end? The biggest
culprit is an out-of-balance or out-of-round tire. As the tread
on the tire wears, it will need to be re-balanced to evenly
distribute the weight of the tire and the wheel. To do this,
small lead weight is attached to the outside of the wheel and a
machine is used to spin the tire and wheel to check balance.
Tires should be balanced and rotated every 12,000 miles
(approximately every four oil changes) to ensure even tire wear
and extend tread life. Out-of-round means the tire has worn
unevenly and cannot be balanced. An out-of-round tire will have
to be replaced. I have even seen new tires that were
out-of-round due to a manufacturing defect.
Hitting a curb or large pot hole can cause the wheel weights to
come off, and sometimes the weights sling off the wheel at high
speed if they were not installed properly. Out-of-round or
out-of-balance will not cause a pull in the front end, but will
definitely cause shakes and shimmies. If you can drive out of a
shake or shimmy by varying the speed of the car, it is a good
clue that you have an out-of-balance problem. A simple way to
check tire balance: if the shimmy is present at one speed, but
better or not present at a different speed, then a balance
problem is likely. An out-of-round tire or a bent wheel will
usually produce a wobble or shimmy at all speeds, and
replacement of the tire or wheel is usually the cure.
Regular tire rotation is the best way to extend the life of a
tire. Ask your mechanic which way to rotate the tires depending
on how the tread is wearing. Crossing tires in an "X" pattern is
usually the standard way to rotate most tires, but moving the
front tires to the back in some cases is recommended to place
the best tires on the front. The majority of the stopping power
of the vehicle comes from the front brakes, so the best tires
should stay on the front for safety. Caution: Some tires are
"directional" and must stay on one side of the vehicle, due to
the fact that the tire was made for the tread to only travel in
one direction.
A vibration or shaking that is felt in the steering wheel only
when the brakes are applied is not a front end alignment
problem, but a brake problem. Have the brakes inspected and make
sure to tell your mechanic about the shaking that you feel in
the steering wheel when you apply the brakes. This vibration may
not be felt by the mechanic on a quick test drive around the
block, so be specific. During this brake inspection, it would
also be a great time to rotate the tires since you are already
paying the labor to remove the wheels.
I have developed a quick and easy to use maintenance schedule
that can help keep you up-to-date on the items mentioned above.
These schedules are free for you to view and print out when you
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