Alignment Arms with Fitting Position Rear Axle

Alignment arms are suspension arms designed to provide additional control over wheel alignment where the standard suspension does not provide enough adjustment. Depending on their position and design, they can be used to change caster, camber or toe.

Some function as adjustable control arms, allowing their effective length or position to be altered, while others use a predetermined offset to provide a specific geometry correction. They can become useful after lowering, lifting or other suspension changes that move alignment away from the desired settings. The correct solution depends on the vehicle, suspension design and alignment angle that needs correction.

What Are Alignment Arms?

Alignment arms are adjustable or offset suspension links used to change wheel geometry beyond the adjustment available from the standard suspension. Their purpose is to provide control over caster, camber or toe where those angles cannot otherwise be brought to the required setting.

The term can describe several different types of suspension arm rather than one universal component.

An alignment arm may replace a control arm or another suspension link and use adjustable length, offset geometry or a different mounting position to change wheel alignment.

The important factor is which alignment angle the arm controls and how that adjustment interacts with the rest of the suspension.

What's the Difference Between Caster, Camber and Toe Arms?

Caster, camber and toe arms are designed to influence different aspects of wheel alignment. Although they can look similar, their position in the suspension determines which part of the wheel geometry they change.

Understanding the difference helps identify the correction required rather than simply fitting an adjustable arm.

Caster Arms

Caster arms influence the fore-aft position or geometry of the suspension in a way that changes the steering axis angle when viewed from the side of the vehicle.

Positive caster can contribute to steering self-centring and straight-line stability. However, more caster is not automatically better. The appropriate setting depends on the suspension design, ride height, tyre setup and intended alignment specification.

A caster correction arm provides additional geometry correction where the original arrangement cannot achieve the required caster setting.

Camber Arms

Camber arms provide adjustment of the wheel's inward or outward tilt when viewed from the front or rear.

Changing ride height can alter camber on many suspension designs. If the original adjustment range is insufficient, an adjustable or offset arm can provide additional correction.

Camber also affects tyre contact and wear, so it should be set as part of a complete wheel alignment rather than adjusted in isolation.

Toe Arms

Toe arms control whether the wheels point slightly inward or outward when viewed from above.

Adjustable toe arms can provide additional correction where the original suspension cannot achieve the desired toe setting, particularly after ride-height or geometry changes.

Toe settings can have a significant effect on tyre wear and vehicle behaviour, so adjustment should be measured accurately using appropriate wheel-alignment equipment.

What Are Adjustable Control Arms?

Adjustable control arms allow the position of a wheel or suspension mounting point to be changed by altering the arm's effective length or geometry. This provides an additional way to correct or fine-tune wheel alignment when the standard control arm does not provide sufficient adjustment.

Not every adjustable control arm controls the same alignment angle.

Depending on its position and suspension design, an adjustable arm may influence:

• Caster
• Camber
• Toe
• Wheel position
• More than one alignment measurement

For this reason, an adjustable control arm should be chosen according to the geometry it is designed to correct rather than adjustment alone.

On-Car vs Off-Car Adjustment

An on-car adjustable arm can be altered while installed, subject to the design and correct adjustment procedure. This can make it easier for an alignment technician to fine-tune geometry while measuring the vehicle.

An off-car adjustable arm may need to be disconnected or removed before its length or position can be changed.

Neither design is automatically better. The correct choice depends on the suspension layout, available access and intended adjustment method.

When Do You Need Alignment Arms?

Alignment arms may be needed when the required caster, camber or toe setting cannot be achieved using the vehicle's existing adjustment range. This can happen after a change in ride height or other suspension modifications that alter the resting geometry.

They can also be useful where additional alignment adjustment is required for a particular suspension setup.

The need should be established from actual alignment measurements rather than assumed simply because the vehicle has been modified.

If the standard adjustment can already achieve the required geometry, an additional adjustable arm may not be necessary.

Rule Out Worn Parts First

Poor alignment is not always caused by insufficient adjustment.

Before using an alignment arm to correct a measurement, inspect the suspension for problems such as:

• Worn control arm bushes
• Worn ball joints
• Damaged suspension arms
• Loose mounting hardware
• Worn wheel bearings
• Damaged springs or dampers
• Incorrect ride height
• Previous accident or impact damage

An adjustable arm should correct a genuine geometry limitation rather than compensate for a worn or damaged component that needs repair.

What Does a Caster Correction Arm Do?

A caster correction arm changes suspension geometry to provide additional caster where the original setup cannot achieve the required setting. Depending on the suspension design, this can be achieved by changing the arm's effective position, length or built-in geometry.

Whiteline caster correction arms can provide predetermined changes in caster on applicable suspension systems, with the amount of correction varying by application.

Caster influences steering geometry, including self-centring behaviour and straight-line stability. However, the correct setting should be determined from the complete suspension setup rather than simply aiming for the largest possible increase.

Caster changes can also interact with camber and wheel position on some suspension designs.

A professional wheel alignment is therefore essential after installation.

What Is a Rear Toe Arm?

A rear toe arm is a suspension link used to control the toe setting of a rear wheel. An adjustable rear toe arm allows its effective length or mounting relationship to be changed so an alignment technician can alter rear toe.

This can be useful when lowering or other suspension changes move rear toe beyond the available factory adjustment range.

Rear toe should be measured rather than estimated visually. Even relatively small changes can influence tyre wear and how the rear of the vehicle responds.

Adjustment should therefore form part of a complete wheel alignment rather than being treated as a stand-alone setting.

Can Alignment Arms Fix Uneven Tyre Wear?

Alignment arms can help when uneven tyre wear is caused by caster, camber or toe settings that cannot be corrected with the existing adjustment range. They will not fix every cause of abnormal tyre wear.

Before changing suspension geometry, check other possible causes such as:

• Incorrect tyre pressures
• Worn suspension bushes or joints
• Damaged components
• Incorrect toe settings
• Excessive or inappropriate camber
• Wheel or tyre problems

The tyre wear pattern and current alignment measurements should be assessed together.

If insufficient adjustment is the problem, the appropriate camber, caster or toe arm can provide the additional correction needed to achieve the intended alignment.

How Are Alignment Arms Fitted?

Fitting an alignment arm generally involves safely supporting the vehicle and suspension, removing the existing arm and installing the replacement at the correct mounting points. Adjustable components then need to be set appropriately before the final wheel alignment.

The exact procedure depends on the suspension design and arm position.

What the Job Involves

A typical installation may involve:

• Safely raising and supporting the vehicle
• Supporting the relevant suspension components
• Removing the existing suspension arm
• Inspecting the mounting points and hardware
• Setting an adjustable arm to an appropriate initial length
• Installing the replacement in the correct orientation
• Tightening fasteners according to the specified procedure
• Settling the suspension at normal ride height
• Checking clearances and suspension movement
• Completing a professional wheel alignment

Where compliant bushes are used, follow the applicable installation procedure for final tightening. Some bush designs need to be tightened with the suspension at normal ride height to avoid unintended preload.

Safety and Wheel Alignment

Never work underneath a vehicle supported only by a jack. Use appropriate stands or workshop lifting equipment and safely support any suspension components that may move when an arm is disconnected.

Fasteners should be tightened to the manufacturer's specified torque and procedure.

A wheel alignment is required after fitting an alignment arm. The arm's purpose is to change suspension geometry, so the final caster, camber and toe measurements need to be checked and adjusted with suitable alignment equipment.

Use a qualified technician if you do not have the equipment or experience required for safe installation and alignment.

Choosing Alignment Arms for Your Vehicle

Choose alignment arms according to the suspension design, arm position and alignment angle requiring correction.

Start with actual alignment measurements and determine whether caster, camber, toe or a combination of settings requires additional adjustment.

Whiteline can assist with fitment if you're unsure which alignment solution suits your suspension setup.

Shop Alignment Arms with Whiteline

Whiteline alignment arms and adjustable control arms provide application-specific geometry correction where additional caster, camber or toe adjustment is required.

Choose camber arms or caster arms for the angle you need to fix.

Choose the correct fitment with the added confidence of Whiteline's Fitment Guarantee, warranty and 30 Day Returns, with fitment assistance available when you need help identifying the appropriate alignment arm for your vehicle.