Wheel Alignment

Major Topics:

3.13 Wheel Alignment:

3.13.1 Wheel Balancing:

3.13 Wheel Alignment:

Wheel alignment is the state in which all wheels on a vehicle are pointed in the optimum direction relative to the road and each other.

Fig 1: Wheel alignment setup

Wheel alignment is a part of standard automobile steering maintenance that consists of adjusting the angles of wheels to the car manufacturer specifications. The purpose of these adjustments is to reduce tyre wear, and to ensure that vehicle travel is straight and true path (without "pulling" to one side).

The key to proper alignment is adjusting the angles of the wheels (tyre) which affect how they make contact with the road. It also refers to the adjustment of a car’s suspension.

The primary and secondary are two main angles of steering geometry for wheel alignment.

The primary angles are the basic angle alignment of the wheels relative to each other and to the car body. These adjustments are the camber, caster and toe.

The secondary angles include numerous other adjustments, such as: SAI (Steering Axis Inclination or kingpin inclination), Included angle, Toe out on turns, Maximum Turns, Toe curve change, Track width difference, Wheelbase difference, Front ride height, Rear ride height, Frame angle and Setback (front & rear).

Original Equipment Manufacturers (OEM) provide wheel alignment specifications when selling their vehicles. You can maximise your vehicle’s steering response and maintain its driving direction by checking your vehicle’s wheels regularly according to the manufacturer’s guidelines. If they have become misaligned you should re-align the suspension as well as the wheels by correcting the wheel balancing & wheel alignment angles, namely: camber, caster, toe-in and toe-out etc.

A proper wheel alignment of your car has provides a better performance of steering while braking & tracking.

Causes of wheel alignment need:

Driving on misaligned wheels is a safety hazard as it can cause your car to drift out of traffic lanes and cause a collision. It also leads to increased friction between your tyres and the road, resulting in the tyre treads rapidly thinning, causing poor road performance and even rapid loss of inflation pressure.

Wheel alignment problems (misalignment) can occur gradually as a result of poorly maintained roads and vehicle wear, or suddenly from impact. The most common causes of slow wheel misalignment are:

    Suspension component wear

    Massive torque and friction from driving placing pressure on shocks, springs and tyres

    Hitting potholes at speed

    Crashing into large road obstacles

    Parking against pavements forcibly

Symptoms and Identification of need of wheel alignment:

Poorly aligned tyres wear aggressively, which shortens their achievable kilometres and results in flat tyres, rapid loss of inflation pressure, and nasty accidents.

There are a couple ways to tell if your car needs a tire alignment. If you've noticed one or more of these indicators, you should have your alignment checked by a licensed service technician immediately.

As wheel misalignment symptoms usually appear gradually, you may not notice the problem initially. However, by paying careful attention to symptoms you can easily save yourself time and money and keep yourself safe behind the wheel.

Wheel alignment problems can become apparent while driving or when your vehicle is stationary. Here are ways to identify poor wheel alignment:

When Driving:

Steering wheel jerking or vibrating and not returning to its normal position after turning a corner and vehicle pull way on to the left or right or one side automatically.

Your steering wheel is off center when driving straight,

When under steering and over steering may arise,

Uneven tyre treads wear,

Tyres squealing while turning,

Excessive shoulder rib wear on the inner or outer shoulder of a tyre (indicating camber setting problems).

While Stationary:

Park your car with the wheels pointing forward and stand a few metres in front of it. Look at both sides of your car and inspect whether your wheels are standing straight up or are slanting inwards or outwards.

Around every 5,000 to 7000 km you must check all your tyres, including the spare. Poor shock absorbers can also cause faster tyre deterioration from force impacting your wheels, so while you’re there have your struts and shocks checked at the same time.

Importance of wheel alignment:

1. Improve Handling: - This helps in controlling the vehicle. Improper handling can be due to vehicle pulling on one side, vibration of the steering wheel.

2. Improves tyre life and performance: - Proper rolling tyre contact on road and prevention of slipping of the tyres due to improper alignment results in better tyre life.

3. Helps in identifying problems: - Improper alignment could be a symptom of something wrong in the vehicle. A check on this can lead to correction in the fault in the vehicle.

4. Ensures Safety: - By keeping the system in order by removing the defective parts, enhances the vehicle systems, especially the suspension system, leading to better safety.

5. Improves fuel efficiency: - By enhancing the performance of various systems, leads to better fuel efficiency from the vehicle.

Importance of wheel alignment according to tyre wear:

Improper wheel or tyre alignment can cause your tyres to wear unevenly and prematurely. Here are some specific types of undue tread wear attributable to misalignment:

FEATHERING

Tires are “feathered” when the tread is smooth on one side and sharp on another. This is usually a sign of poor toe alignment.

CAMBER WEAR

This strain of tread wear means the inside or outside of the tread is significantly more worn than the center of the tread. As its name implies, positive or negative camber causes this type of wear.

HEEL/TOE WEAR

This happens when one side of your tread blocks wears down more quickly than the other in a circumferential direction. When you run your hand over the tread, it will look and feel like saw teeth when viewed from the side. Heel/toe wear could be a sign of under inflation and/or lack of rotation.

If you’re experiencing any of these unusual wear patterns, you should have a technician check your alignment. While tire wear prevention is a good reason to keep your wheel alignment in check, the consequences of misalignment can also play out in overall vehicle performance. A car that pulls to one side or steers erratically, for example, probably has an alignment problem.

3.13.1 Wheel Balancing:

Fig 2: Wheel balancing

Distinct from wheel alignment, tyre or wheel balancing refers to compensation for any weight imbalances in the tyre or wheel combination and is often performed in conjunction with wheel alignment. There are two basic types of wheel imbalance that need correction – static (single plane) and dynamic (dual plane).

Static balance addresses balance on only one plane – vertical movement which can cause vibration. A dynamic imbalance, on the other hand, addresses balance in two planes – vertical movement and lateral movement. Both types of imbalance require the use of a special balancing machine to help even things out.

Fig 3: Wheel balancing machine

To begin balancing your car wheels, a technician will mount them on the correct rims and adjust the pressure to optimal inflation. Then each tire goes on the center bore of a balancing machine. The machine spins the tire at a high speed to measure the wheel/tire combination imbalance. It signals how much weight the tech should add to balance out the tire and the areas where said weight is needed.

Wheel balancing is essential for proper tyre care for the same reason as wheel alignment: prevention of premature tread wear. Having wheel aligned and balanced every 5,000 to 6,000 km can help maximize their lifespan and overall performance. And wheel balancing is performing before wheel alignment for meeting proper steering geometry.