Reader Question: My
car shakes and vibrates on the freeway, does this mean my car needs a vehicle alignment?
concerned car owner,
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 tire wear, but will cause
a pull in one direction, and this problem is commonly found on wrecked
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.
Did you find
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