Wheel Alignment: What's Involved?

A wheel alignment is a crucial aspect of vehicle maintenance, often misunderstood by many car owners. It's not simply about adjusting the wheels; it's a precise geometric adjustment of your car's suspension and steering components to bring them back to the manufacturer's original specifications. Performing this service regularly can significantly impact your car's handling, tyre wear, and overall safety. But what exactly does a wheel alignment service include? Let's delve into the details.

Understanding Wheel Alignment Terminology

Before we explore the service itself, it's important to grasp some fundamental terms related to wheel alignment:

• Camber: This refers to the inward or outward tilt of the top of the tyre when viewed from the front of the vehicle. Too much negative camber (top tilted inward) or positive camber (top tilted outward) can lead to uneven tyre wear and affect handling.
• Caster: Caster describes the angle of the steering axis when viewed from the side of the vehicle. It influences steering stability and the tendency for the steering wheel to return to centre after a turn. Positive caster generally improves straight-line stability.
• Toe: Toe is the angle of the tyres when viewed from above. If the front of the tyres point inwards, it's called 'toe-in'; if they point outwards, it's 'toe-out'. Incorrect toe settings can cause rapid tyre wear and make the car wander.
• Thrust Angle: This is the direction in which the rear axle is pointing relative to the vehicle's centre line. If the thrust angle is incorrect, the car will not track straight, even with the front wheels aligned.

The Wheel Alignment Process: Step-by-Step

A professional wheel alignment service typically involves several key steps performed by a trained technician using specialised equipment:

1. Initial Inspection and Assessment

The process begins with a thorough visual inspection of your vehicle's suspension and steering components. The technician will check for any signs of damage, wear, or looseness in parts such as:

• Tie rod ends
• Ball joints
• Control arms
• Bushings
• Shock absorbers and struts
• Steering rack
• Tyres (for wear patterns and proper inflation)

Any worn or damaged parts must be replaced or repaired before an alignment can be performed, as these issues can prevent a proper alignment or cause it to quickly go out of specification again.

2. Vehicle Placement on the Alignment Rack

Your car will be carefully driven onto a specialised alignment rack. This rack has lifting capabilities and is equipped with sensors or targets that attach to each wheel. These sensors communicate with a computerised alignment machine that measures the current angles of your wheels.

3. Pre-Alignment Checks

Before the actual adjustments are made, a few crucial checks are performed:

• Tyre Pressure: Ensuring all tyres are inflated to the correct pressure is vital. Incorrect tyre pressure can affect the readings and the alignment itself.
• Wheel Bearing Play: The technician will check for any excessive play in the wheel bearings, which could skew the alignment readings.
• Ride Height: For some vehicles, especially those with adjustable suspension, the ride height is checked to ensure it's within specification.

4. Computerised Measurement

Once the vehicle is secured on the rack and the sensors are attached, the alignment machine takes precise measurements of the current camber, caster, toe, and thrust angle for each wheel. This data is then compared against the vehicle manufacturer's specifications, which are stored in the machine's database.

5. Adjustments

Based on the measurements and the manufacturer's specifications, the technician will make the necessary adjustments to the suspension and steering components. This typically involves:

• Adjusting Camber: Often adjusted by loosening and rotating the strut assembly or by using shims in the suspension.
• Adjusting Caster: Usually adjusted by repositioning the control arm or by using shims.
• Adjusting Toe: This is typically done by turning the tie rod ends. Adjusting the toe on one side will require a corresponding adjustment on the other to maintain the steering wheel centred.
• Adjusting Thrust Angle: This may involve adjusting the rear axle or components in the rear suspension, depending on the vehicle's design.

The technician will adjust each parameter until it falls within the manufacturer's acceptable range. The goal is to achieve a perfectly balanced setup across all wheels.

6. Final Measurement and Verification

After the adjustments are made, the alignment machine takes a new set of measurements to confirm that all angles are now within the specified tolerances. The technician will verify that the steering wheel is straight and centred when the vehicle is travelling in a straight line.

7. Test Drive

In many cases, a brief test drive will be conducted to ensure the vehicle tracks straight, handles correctly, and that the steering wheel is centred. This is a crucial final check to guarantee the quality of the work performed.

Why is a Wheel Alignment Important?

Regular wheel alignments are essential for several reasons:

• Tyre Longevity: Properly aligned wheels ensure that your tyres wear evenly, significantly extending their lifespan and saving you money on premature replacements. This is perhaps the most direct benefit for most drivers.
• Improved Fuel Efficiency: Misaligned wheels create more rolling resistance, meaning your engine has to work harder, consuming more fuel. Correcting alignment can lead to better MPG.
• Enhanced Safety: A car with proper alignment will handle predictably, steer more easily, and maintain stability, especially at higher speeds or during emergency manoeuvres. This contributes to a safer driving experience.
• Better Handling and Ride Comfort: Correct alignment ensures your car steers and handles as the manufacturer intended, providing a smoother, more comfortable ride and reducing driver fatigue.
• Preventing Component Wear: Poor alignment can put undue stress on suspension and steering components, leading to premature wear and potentially costly repairs.

When Should You Get a Wheel Alignment?

It's advisable to have your wheel alignment checked and adjusted:

• When purchasing new tyres.
• After any suspension or steering repairs or replacements.
• If you hit a significant pothole or curb.
• If you notice uneven tyre wear.
• If the vehicle pulls to one side or the steering wheel is off-centre when driving straight.
• As part of your regular vehicle maintenance schedule, typically every 12-18 months.

Frequently Asked Questions (FAQs)

Q1: How long does a wheel alignment service take?
Typically, a standard wheel alignment service takes between 45 minutes to 1.5 hours, depending on the complexity of the vehicle's suspension and the extent of any necessary adjustments.

Q2: Can I do a wheel alignment myself?
While basic toe adjustments might be possible for some DIY enthusiasts, a full and accurate wheel alignment requires specialised equipment and expertise. It is strongly recommended to have this service performed by a qualified professional.

Q3: What is the difference between a two-wheel and a four-wheel alignment?
A two-wheel alignment adjusts only the front wheels, suitable for front-wheel-drive vehicles where the rear wheels are fixed. A four-wheel alignment adjusts all four wheels and is necessary for rear-wheel-drive, all-wheel-drive, and four-wheel-drive vehicles, as it also addresses the thrust angle.

Q4: How much does a wheel alignment cost?
The cost can vary depending on your location, the type of vehicle, and the garage. However, you can generally expect to pay anywhere from £50 to £150 for a standard four-wheel alignment. It's always best to get a quote from your local garage.

Q5: Will a wheel alignment fix my car pulling to one side?
In many cases, yes. A pulling issue is often caused by incorrect alignment settings, particularly toe or camber. However, if the pulling persists after an alignment, it could indicate other underlying issues like worn suspension components or uneven tyre wear.

Conclusion

A wheel alignment service is a comprehensive procedure that goes far beyond a simple adjustment. It involves meticulous measurement and adjustment of key suspension and steering angles to ensure your vehicle performs optimally. By understanding what's involved and its importance, you can make informed decisions about your car's maintenance, leading to safer driving, reduced costs, and a more enjoyable driving experience.