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Front Wheel Alignment

Suketu Mehta Apr 15, 2020
Front wheel alignment becomes necessary when the car doesn't move properly in a straight line. This Story explains why and when an alignment is necessary, as well as how to align the wheels yourself.
Wheel alignment in a car refers to adjusting the wheel angles in such a manner that they are perpendicular to the ground and parallel to each other. These adjustments are carried out to ensure that the tires last for a long time and the car moves in a straight line while driving. Whenever there is unexpected wear and tear of tires, the car drifts to one side, or there is vibration at the steering while driving very fast, it is an indication that wheels need to be aligned properly.
It is always better to get an alignment job done from a car shop or a tire specialist. Though the process is not very tough, there is certain amount of basic knowledge required for aligning car wheels in their ideal position. Wheel alignment requires three measurements--caster, camber, and toe.

Basic Terms Explained

Caster

Caster is defined as the tilting of the topmost point on the axis of the car steering. The tilting is either backward or forward, when seen from the sides of the car. A forward tilt is denoted by a negative (-) sign, while a backward tilt is denoted by a positive (+) sign.
Wearing of the tires is not affected by caster, but it does affect the steering's direction control. The car body has to be kept at its predetermined height as it has a bearing on the caster. A positive caster is a result of the rear-side of the car being lower than the normal height.

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In case the rear-side is higher than the normal height, the front suspension shows a less positive caster. If there is a difference between caster values of two wheels, the wheel starts pulling towards the car's center. This makes the vehicle drift towards the side, which has a lower caster value.

Camber

The angling of the vertical axis of the car when seen from the front and the angle between the vertical axis of the wheels used for steering, is known as camber. If the wheels angle inwards from the top, the camber value is negative (-), while the value is positive (+) when the wheels angle outwards from the top.
Directional control as well as wearing of the tires is affected by camber settings. If the camber is too positive, the tires and suspension parts will wear down quickly. A high negative camber will wear the tires as well as suspension parts on the inside.
In case the difference in camber value for two tires, which are side-by-side, is more than 1 degree, it will result in the car being pulled to the side which has a higher positive camber.

Toe

Toe measurement defines how much the front wheels have turned on the inside or outside from a straight position. If the wheels have turned on the outside, the toe value is negative (-); when the wheels have turned on the inside, the toe value is positive (+). Usually, the value of toe is only a fraction of a degree. The toe makes sure that the wheels run parallel to each other when the car is moving. Steering imbalance and quick wearing of tires are possible results of a faulty toe adjustment.

Realigning

It is always recommended to get the realignment done by a professional, as it requires some technical knowledge and specific equipment. While the method below is effective, only attempt to do it yourself if you have some knowledge about cars.
  • To start with, arrange for two PU plastic bags and one laser pointer.
  • Park the car on a flat surface, and place a plastic bag behind each front wheel.
  • The plastic bag helps to keep the wheel at a minimum frictional position.
  • Reverse the car a little bit to get both front wheels on the plastic bags. Adjust the car steering to its original straight position.
  • Using a laser pointer, adjust the beam from the tire's front edge to the rear edge in a slight downward position, so that the beam falls on the ground and forms an angle.
  • Repeat the process for the other wheel to get its total toe angle.
  • There will be an adjustment screw under the car wheel which needs to be loosened. Adjust the rod as per requirements to either increase or decrease the toe angle.
  • The ideal angle is 0 for cars with a back wheel drive. The angle for front wheel drive cars need to be calculated and adjusted accordingly.

Cost

Wheel alignment costs mainly involve labor expenses, and hence costs differ from place to place. There are several tire centers and car shops which provide this service, details of which can be found online or in any business directory.
The cost ranges from US $100 to US $500, depending upon the area. To align all four wheels, the cost could be anywhere between US $100 to US $200.
Wheel alignment should be done once a year or after every 10,000 miles the car runs, whichever is earlier. Modern cars have an advantage as they require only a toe adjustment and no caster or camber adjustments.