WHEEL ALIGNMENTS
While it's often referred to simply as an "alignment" or "wheel alignment," it's really complex suspension angles that are being measured and a variety of suspension components that are being adjusted. This makes an alignment an important suspension-tuning tool that greatly influences the operation of the vehicle's tyres.
Out-of-alignment conditions occur when the suspension and steering systems are not operating at their desired angles. Out-of-alignment conditions are most often caused by spring sag or suspension wear (ball joints, bushings, etc.) on an older vehicle. They can also be the result of an impact with a pothole or curb, or a change in vehicle ride height (lowered or raised) on any vehicle regardless of age.
Incorrect alignment settings will usually result in more rapid tyre wear. Therefore, alignment should be checked whenever new tyres or suspension components are installed, and any time unusual tyre wear patterns appear. The trick with alignments is that even if your car has just had one, hitting a posthole, bump or gutter can immediately throw it out. Alignment should also be checked after the vehicle has encountered a major road hazard or curb.
Front-End, Thrust Angle and Four-Wheel Alignment
The different types of alignments offered today are front-end, thrust angle, and four-wheel. During a front-end alignment, only the front axle's angles are measured and adjusted. Front-end alignments are fine for some vehicles featuring a solid rear axle, but confirming that the front tyres are positioned directly in front of the rear tires is also important.
On a solid rear axle vehicle, this requires a thrust angle alignment that allows the technician to confirm that all four wheels are "square" with each other. Thrust angle alignments also identify vehicles that would "dog track" going down the road with the rear end offset from the front. If the thrust angle isn't zero on many solid rear axle vehicles, a trip to a frame straightening shop is required to return the rear axle to its original location.
On all vehicles with four-wheel independent suspensions, or front-wheel drive vehicles with adjustable rear suspensions, the appropriate alignment is a four-wheel alignment. This procedure "squares" the vehicle like a thrust angle alignment, and also includes measuring and adjusting the rear axle angles as well as the front.
Not all vehicles are easily adjustable or fully adjustable. Some vehicles require aftermarket kits to allow sufficient adjustment to compensate for accident damage or the change in alignment due to the installation of lowering springs.
The primary static suspension angles that need to be measured and adjusted are caster, camber, toe and thrust angle. Modern cars commonly have toe adjustments, so not all measurements are able to be done. However there are kits that can be bought for these adjustments to be made. Here's a quick definition of each angle and its influence on a vehicle and its tyres.
Caster
Caster is the angle of the steering axis (the part of the suspension that supports the wheel and tyre assembly). Viewed from the side of the vehicle, an imaginary line drawn between the centers of the upper and lower ball joints forms an angle with true vertical; this is defined as caster. The illustration below shows whether this angle is referred to as positive or negative. Caster is important to steering feel and high-speed stability.
Camber
Viewed from the front of the vehicle, camber describes the inward or outward tilt of the tyre. The illustration below shows whether this tilt is referred to as positive or negative. The camber adjustment maximizes the tyre-to-road contact and takes into account the changes of force when a vehicle is turning. Camber is the one adjustment that can be set according to driving habits. Generally, if you drive more aggressively when cornering, more negative camber can be set. If you drive on highways and do very little hard cornering, more positive camber can be set.
Too much positive camber will result in premature wear on the outside of the tire and cause excessive wear on the suspension parts.
Too much negative camber will result in premature wear on the inside of the tire and cause excessive wear on the suspension parts.
Toe
Viewed from above the vehicle, toe describes whether the fronts of the tyres are closer (toe-in) or farther apart (toe-out) than the rears of the tyres. The illustration below shows this relationship. Toe settings vary between front and rear wheel drive vehicles. In a front wheel drive vehicle, the front wheels try to pull toward each other when the vehicle is in motion, which requires a compensating toe-out setting. A rear wheel drive vehicle works just the opposite, necessitating a toe-in setting. Stated differently, toe is set to let the tyres roll in parallel (at zero toe) when the vehicle is in motion. This is the most common wheel alignment adjustment made, as most modern vehicles dont have the adjustments for camber or caster.
Thrust Angle
Thrust angle is the direction that the rear wheels are pointing in relation to the center line of the vehicle. If the thrust angle is not zero, then the vehicle will "dog track" and the steering wheel will not be centered. The best solution is to first adjust the rear toe to the center line and then adjust the front toe. This is normally done during a 4-wheel alignment as long as the rear toe is adjustable. If the rear is not adjustable, then the front toe must be set to compensate for the thrust angle, allowing the steering to be centered.
So When Do I Need A Wheel Alignment ?
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If your steering wheel isn't straight or your car pulls to either side or wanders on straight roads
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After an encounter with a particular nasty pothole or kerb
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When you are replacing your tyres
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We recommend a wheel alignment twice a year to ensure your vehicle's safety, to improve handling and to help maximise the life of your tyres.
So if you’re not sure whether your wheels are out of alignment, it’s worth bringing your car to Taleb Tyres to have them fixed; it can be a lot cheaper than prematurely replacing a set of tyres.
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