Suspension Secrets Adjustable Rear Billet Traction Arms - BMW E90/E92 M3

Suspension Secrets Adjustable Rear Billet Traction Arms – BMW E90 / E92 M3

Improve acceleration, rear axle stability and corner-exit traction with Suspension Secrets Adjustable Rear Billet Traction Arms for the BMW E90 and E92 M3.

The factory rear traction arms use a folded-plate, non-adjustable construction which can flex under load. During hard acceleration, this movement can affect rear suspension geometry and introduce unwanted toe change, reducing how precisely the rear axle responds to throttle inputs.

Suspension Secrets replaces the standard arms with a solidly mounted billet design engineered to reduce unwanted flex and provide a more direct connection between the rear suspension and chassis.

The arms also feature two mounting configurations, allowing either an OEM-equivalent position or an increased-length track position that alters the rear suspension kinematics to generate additional mechanical traction.

Why Upgrade the Rear Traction Arms?

The rear traction arms influence how the wheel and hub move as the suspension compresses under acceleration.

Reducing unwanted compliance and controlling this movement more precisely can provide:

• Improved acceleration
• Increased straight-line stability
• Greater corner-exit traction
• More responsive rear axle behaviour
• Reduced unwanted toe change
• Higher potential corner-exit speeds
• Improved chassis feedback
• Greater control over rear suspension kinematics

Key Features

• Designed for BMW E90 / E92 M3
• Billet adjustable rear traction arm construction
• Replaces the factory folded-plate arms
• Solid-mounted design
• Reduces unwanted arm flex
• Helps reduce dynamic toe change
• Improves rear axle response to throttle
• Two shim configurations supplied
• OEM-equivalent mounting position
• Increased-length track mounting position
• Track position alters rear axle kinematics
• Designed to increase mechanical traction
• Billet aircraft-grade 6082 T6 aluminium
• Corrosion-resistant stainless steel components
• Motorsport-spec Fluro bearings
• Designed and manufactured in the UK

The Limitation of the Factory Traction Arms

The standard BMW rear traction arms are non-adjustable folded-plate components.

Under high loads, particularly during aggressive acceleration, these arms can flex.

This movement can allow the wheel geometry to change dynamically and make the rear axle feel less immediate when power is applied.

Solid-Mounted Billet Construction

Suspension Secrets designed these arms around increased strength and reduced compliance.

The solidly mounted construction helps prevent the arm from flexing under acceleration.

This can make the rear suspension behave more consistently and improve the connection between throttle inputs and rear axle response.

Reduced Dynamic Toe Change

Unwanted movement in the factory arms can contribute to changes in rear toe as the suspension is loaded.

Toe has a significant influence on:

• Straight-line stability
• Acceleration
• Rear axle behaviour
• Corner-exit confidence

Reducing this movement helps keep the rear geometry closer to the settings chosen during alignment.

Improved Acceleration

The more rigid arm construction helps the rear suspension react more consistently as torque is transferred through the rear tyres.

Potential benefits include:

• More effective traction
• Improved rear axle response
• Greater confidence under full throttle
• More predictable acceleration behaviour

Increased Corner-Exit Traction

Corner exit places significant combined lateral and acceleration loads through the rear suspension.

Keeping the geometry more stable can help the rear tyres maintain a more consistent relationship with the road surface as throttle is applied.

This can allow the driver to use the available grip more effectively on corner exit.

More Responsive Rear Axle

Reducing compliance means the rear axle can react more immediately to changes in throttle.

The car can therefore feel more directly connected when transitioning from:

• Maintenance throttle
• Partial throttle
• Full acceleration

For performance driving, this can improve confidence and make the chassis easier to control close to the limit.

Increased Straight-Line Stability

More consistent rear geometry can also improve stability during hard acceleration in a straight line.

This is particularly useful on higher-grip setups where greater loads are being transferred through the rear suspension.

Two Shim Configurations

A major feature of the Suspension Secrets Rear Traction Arms is the supplied shim system.

Two configurations are available:

• OEM hole position
• Fixed increased-length track position

This allows the arms to be configured around the intended use of the vehicle.

OEM Position

The OEM-position shim configuration maintains the original mounting geometry while still providing the benefits of the stronger, solidly mounted traction arm design.

This makes it well suited to road and fast-road applications where reduced compliance is the main objective.

Increased-Length Track Position

The second shim configuration creates a fixed increased-length position intended for track use.

This changes the rear axle kinematics by altering the arc through which the control arm moves as the suspension compresses.

Altered Rear Axle Kinematics

With the additional traction shims installed, the path of the rear control arm is altered.

As the suspension compresses under acceleration, such as when applying throttle on corner exit, the revised geometry is designed to generate additional mechanical grip at the leading edge of the tyre.

This makes the track configuration particularly useful when trying to maximise rear traction from a more developed suspension setup.

Increased Mechanical Grip

Rather than simply relying on tyre compound or damper settings, the track shim position changes how the suspension itself behaves under compression.

The aim is to help the rear tyre produce more usable traction as power is applied.

This can contribute to:

• Improved corner-exit acceleration
• Increased mechanical grip
• Greater rear axle stability
• Higher potential exit speeds

Road & Track Configuration

The dual-position shim arrangement makes these arms useful across a range of builds.

The OEM-equivalent position is suited to:

• Road cars
• Fast-road builds
• Weekend performance cars
• Clubsport setups

The increased-length position is aimed more towards:

• Trackday cars
• Semi-slick tyre setups
• Dedicated circuit builds
• Performance-focused geometry setups

Motorsport-Spec Fluro Bearings

Suspension Secrets uses motorsport-spec Fluro bearings to provide precise articulation while reducing unwanted compliance.

This helps maintain more consistent geometry under high suspension loads.

6082 T6 Aluminium Construction

The arms are manufactured using billet aircraft-grade 6082 T6 aluminium.

This provides a strong and lightweight structure suited to demanding suspension applications.

Corrosion-Resistant Stainless Steel

Corrosion-resistant stainless steel is used throughout the relevant hardware and adjustment components to improve durability in an exposed underbody environment.

Designed & Manufactured in the UK

Suspension Secrets designs and manufactures its suspension components in the UK.

The traction arms have been developed specifically around the behaviour and kinematics of the E9x M3 rear suspension.

Works Well With Other Rear Geometry Upgrades

These traction arms work particularly well alongside:

• Adjustable rear toe arms
• Adjustable rear camber arms
• Adjustable rear upper third links
• Solid rear control arm bushes
• Solid rear subframe bushes
• Coilovers
• Performance geometry setups

Together, these components allow much greater control over the behaviour of the rear axle.

NVH Considerations

Because these arms use solid mounting and motorsport-spec bearings rather than compliant factory rubber, some increase in noise, vibration and harshness may be possible.

This is a performance-focused component designed primarily to improve rear axle precision and traction.

Professional Installation Recommended

Professional installation is strongly recommended.

The chosen shim position should be selected based on the intended use and overall suspension setup of the car.

Geometry Setup Essential

A full four-wheel geometry setup should be carried out after installation.

The final settings should consider:

• Rear toe
• Rear camber
• Ride height
• Shim position
• Tyre specification
• Road or track use
• Overall chassis balance

For track-focused cars using the increased-length position, setup by a specialist familiar with performance suspension kinematics is recommended.

Vehicle Fitment

BMW M3 E90 / E92

Compatible models:

• BMW E90 M3 Saloon
• BMW E92 M3 Coupe

What's Included?

Each kit includes:

• 1 pair Suspension Secrets Adjustable Rear Billet Traction Arms / Trailing Links
• Shim kit for OEM-equivalent mounting position
• Shim kit for fixed increased-length track position

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