Imagine this: cruising along the interstate with the soft breeze of the fresh country air in harmony with the soft purr of your well tuned engine and noiseless vibrations of the smooth traction of rubber along the evenly paved road. Take out anything from the previous statement and you would be having a bad time, yet you do not notice your car slowly and gradually degrade. With a few loosened joints somewhere, a leak starting to occur in the oil filter, the engine accumulating carbon deposits, mufflers becoming clogged with soot and impurities, air conditioning system losing its Freon, tires getting flatter, or perhaps your wheels getting misaligned.

While you may notice these after they a set amount of its degradation has taken effect, these are manageable, easily corrected, and do not  pose much of a threat to the driver, well except for the few such as wheel alignment. Driving with a bad case of this may be dangerous not only to the car’s driver, but to the others in the road. Handling becomes a little more difficult as you would notice your vehicle steering over to one direction with occasional difficulty in maneuvering, or rather notice that your gas consumption is quite more than the usual average, or perhaps literally feel the miniscule wobbling of your car as it runs especially in much lower speeds.

Overall performance of your car is therefore lessened, and constant neglect of this issue even when it is already obvious hastens the degradation of your wheels, car joints, engine, and the like. Your engine would have to exert more just to overcome the resistance of the wheels not being aligned as it rolls on the road, the car joints may bear the extra burden of the added generated weight as well, and the tires may wear out unevenly and lose traction that may be the cause of loss of control and eventually accidents.

Wheel balancing is required to avoid all these hassles of driving. Basically, wheel alignment and balancing is one of the most fundamental and crucial automotive maintenance procedures. This is done periodically to prevent “pulling” during driving, reduce tire and joint wear, and provide a comfortable and typically risk-free driving. Maximizing the alignment of all the tires to face only one direction which is straight front and parallel, and having all the angle of the tires the same so that tires are flat on the ground to avoid one sided wearing are the two main objectives of wheel alignment and balancing.

Knowing The Terms

These terms are the factors which may contribute to wheel misalignment over time and should be periodically serviced for maintenance:

Camber is simply the angle when the vehicle rests on the wheels. Having the wheel on the ground tilt towards inside, it is referred to as a positive camber while having the same contact wheel area tilted away from the car makes it a negative camber. This is the main reason why “pulling” occurs as the part of the wheel in constant contact with the road gets worn out faster than the other areas, causing the vehicle to eventually start veering towards the side with positive camber. This also affects the structure and integrity of the joints holding that affected wheel, specifically the strut and the spindle assembly. And when the camber is significantly affected, it almost always follow that the Toe also is affected.

Toe. It is referred toe the area of the wheel at the front most part as it is driven around. Another way of saying is that as camber is the vertical alignment of the wheel, the toe is the horizontal alignment. This aspect is also very critical, especially to the front wheels of front engine vehicles as wearing of tires is significant even with just having your alignment off by at least 1/32 of an inch.

Caster refers to the joint or the steering pivot that holds the wheels. When viewed from the side, it may technically be considered as the angle of the steering axis. Different vehicles have different casting angles, the heavier duty variants getting a closer to a 90 degree from the ground to lessen handling problems. While it may not have a direct effect on the wearing out of the tires, it may contribute to a fixed effect on it especially when the vehicle underwent accidents which may have compromised the structure of the immediate area.

Steering Axis Inclination is the counterpart of the caster in terms of perspective angle of the joint. This refers to the view when facing the front of the vehicle. In simpler terms it is like facing a person leaning against the corridor wall, the angle of the arms and back when viewed from the side as the caster, and the angle of the supporting arms when viewed from the front as the steering axis inclination or SAI. Supposedly, this should be fixed and non-adjustable, but bent parts from bumps or previous mishandling may cause this angle to be different from each wheel. When this happens, it causes pulling when taking small curves and maneuvering tight spots.

Scrub Radius is simply the width or distance of the centerline of the SAI and the center of the wheel (supposing that the wheel base is pressed flat on the road). Having a slight difference per wheel would cause pulling to happen greatly to the wheel with a higher scrub radius due to a wider contact that produces more traction.

Set Back is referred to as the condition wherein the wheels are not equally “squared out” at the base of the car. Imagine the wheels as corners of a square. To deviate the square so that one side will be ahead of the opposite parallel side will form a parallelogram, which when applied to the physics of wheels being balanced for a car to maneuver, would cause steering to be uncentered. It is like having your feet in roller skates, with one set back a few inches than the other, and trying to turn with both feet planted on the ground would cause you to notice the set back foot turning faster and creating that “pull”. This should not normally be the case and the presence of it may indicate a bent part from manufacturing defect or from a previous accident or heavy wear from underside bumps.

Thrust Angle is the reference of alignment of the rear wheels to the centerline of the automobile. When misalignment by a deviation of the angle to the centerline is evident, driving the automobile will give that distinct wobble referred to as the “dog track”. This is evident when viewed by someone driving behind your automobile and sees that the rear part of the vehicle is swayed to one side, creating a view that the car is traveling a little sideways. Funny and cute as it looks when viewed on dogs strutting, it looks ridiculous for automobiles and it is a road safety risk too.

Steering Center is the most common and easiest to notice for worn out tires and misaligned settings. Normally your steering wheel should just stay at a balanced state when cruising in a straight path line. However, when wheel misalignment occurs, you may notice that your steering wheel may bob erratically from left to right may indicate that there is possible caster or toe misalignment. Another scenario would be to see the steering wheel turn itself to one side which would already indicate “pulling” towards that side. Either which, one should seek the help of professional services to properly align them.

Wheel Rotation is the process of periodically rotating the tires so that each tire would be able to be placed in each of the four wheel placements. Wheel rotation is done because each wheel is subjected to different set of forces at different wheel placement areas. For example, the front passenger side wheel gets the most load at all times because of the presence of the front side engine area plus the driver’s weight. The front passenger does not get exposed as much, even more so with the rear tires. Wheel rotation is also done to ensure that there is eventual balanced load and wear experienced by each tire, supposing that the other factors for wheel alignment stays relatively constant.

Wheel alignment and balancing technically should not always happen each time wheel rotation is done. For the very purpose considering that the balancing and aligning should be still good and also as to provide consistent and constant settings to the other tire to be put in each wheel placement, only when changing new rims or tires would be plausible for a necessary checkup.

The importance of routine wheel alignment

Normally, wheel alignment should only be done whenever you feel that slightest wobble, “pull”, or an obvious view of a misaligned wheel. Otherwise, wheel rotation would be the most important method to consider for the meantime, making sure that it is done every 7,500 to 10,000 miles. Spending around on average $20 – $40 for a computerized service, it would not be much of a concern with the budget.