MMX Front Control Arm Upgrade Bushings | F2X
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MMX Front Control Arm Upgrade Bushings – BMW F2X & F3X
Sharpen the front-end response of your BMW F2X or F3X with the MMX Front Control Arm Upgrade Bushings.
Designed for performance-focused BMW M135i, M140i, M235i, M240i, 335i, 340i, 435i and 440i models, these spherical bushings replace the softer factory rubber control arm bushes with a much more precise joint designed to reduce deflection under heavy braking and cornering.
By helping maintain more consistent front wheel alignment under load, the MMX bushings can improve steering response, turn-in precision, stability and tyre behaviour on both fast-road and track-focused builds.
Why Upgrade the Front Control Arm Bushings?
The factory BMW rubber control arm bushes are designed to provide a balance between handling, refinement and noise isolation.
Under hard braking and cornering, however, rubber can compress and deflect.
That movement allows the control arm to shift slightly relative to the chassis, which can alter wheel alignment as the car is loaded.
The MMX spherical bushings reduce this movement by replacing the compliant rubber joint with a more rigid motorsport-style spherical bearing.
Potential benefits include:
- Sharper steering response
- More precise turn-in
- Improved stability
- Reduced suspension deflection
- More consistent front toe under load
- Improved steering feedback
- Better tyre behaviour
- More direct chassis response
Key Features
- MMX Front Control Arm Upgrade Bushings
- Spherical bearing design
- Designed for BMW F2X and F3X
- Replaces the factory rubber bushings
- Helps maintain front wheel alignment under load
- Reduces unwanted suspension deflection
- Improves steering feedback
- Sharpens turn-in
- Improves braking stability
- Helps maintain front toe under hard cornering
- Can reduce uneven tyre wear caused by geometry movement
- Anodised 7075 aluminium construction
- Stainless-steel spacers
- High-strength spherical bearing
- 3D-printed press tool included
- Sold as a pair
- Professional installation recommended
- MMX part number MMR45-0501
Reduces OEM Rubber Bush Deflection
Rubber suspension bushes inevitably deform when subjected to load.
During aggressive driving, forces from braking, steering and cornering can compress the factory bush and allow the wheel position to move away from its static alignment setting.
The MMX spherical design substantially reduces this compliance.
This allows the control arm to remain more accurately positioned relative to the chassis.
Helps Maintain Front Toe Under Load
Toe is particularly sensitive to movement within the front suspension.
If the control arm shifts under braking or cornering, the wheel can dynamically move into a different toe position.
That can affect:
- Steering precision
- Straight-line stability
- Turn-in behaviour
- Tyre temperature
- Tyre wear
The MMX bushings are designed to keep front toe more stable under these conditions.
Sharper Steering Response
Removing compliance from the control arm mounting point creates a more direct relationship between steering input and front-wheel movement.
This can make the car feel:
- More responsive
- More connected
- More precise
- More immediate on turn-in
For fast-road driving, the difference can be particularly noticeable on cars already fitted with upgraded suspension and performance tyres.
Improved Braking Stability
Heavy braking places substantial longitudinal load through the front suspension.
With softer rubber bushings, the control arm can move relative to the chassis.
Reducing that movement helps maintain more consistent wheel alignment during braking.
This can improve:
- Straight-line stability
- Brake confidence
- Steering consistency
- Predictability under threshold braking
Improved Tyre Performance
MMX specifically highlights tyre performance as one of the benefits of reducing front toe change.
If the front wheels remain more consistently aligned under load, the tyre can operate more predictably.
Potential benefits include:
- More consistent tyre temperatures
- Reduced irregular wear
- Better use of the contact patch
- Greater grip consistency
This is particularly valuable for cars running high-performance road tyres or semi-slicks.
7075 Aluminium Construction
The MMX bushing housings are manufactured from anodised 7075 aluminium.
7075 is a high-strength aluminium alloy well suited to highly loaded suspension components.
It provides a strong balance of:
- Low weight
- High mechanical strength
- Precision
- Durability
The anodised finish also provides additional surface protection.
Stainless-Steel Spacers
The kit uses stainless-steel spacers around the spherical bearing assembly.
These provide:
- High strength
- Corrosion resistance
- Accurate locating surfaces
- Long-term durability
The combination of 7075 aluminium and stainless steel gives the assembly a high-quality motorsport-style construction.
High-Strength Spherical Bearing
At the centre of the MMX assembly is a high-strength spherical bearing.
Unlike rubber, the bearing allows the suspension to articulate without introducing the same degree of unwanted elastic movement.
This creates a much more precise connection between the control arm and chassis.
Spherical Bushings vs OEM Rubber
Factory Rubber Bushings
Prioritise:
- Comfort
- Noise isolation
- Vibration reduction
- Everyday refinement
MMX Spherical Bushings
Prioritise:
- Steering precision
- Geometry control
- Reduced deflection
- Improved response
- Performance feedback
For a standard road car, the factory bushes provide greater refinement.
For a modified fast-road or track car, the additional precision of the MMX spherical design can be much more desirable.
NVH Considerations
Spherical bearings remove much of the compliance provided by rubber.
As a result, some additional:
- Noise
- Vibration
- Road texture
- Suspension feedback
may be transmitted into the cabin.
This is an inherent trade-off of replacing a compliant rubber mounting with a motorsport-style bearing.
For customers prioritising maximum refinement, the factory rubber bushes may remain more suitable.
Ideal for Lowered Cars
The MMX bushings work particularly well on cars already fitted with suspension modifications such as:
- Lowering springs
- Height-adjustable springs
- Coilovers
- Performance dampers
- Uprated anti-roll bars
- Adjustable droplinks
Once the suspension has been made more performance-focused, reducing control arm deflection helps preserve the intended geometry more effectively.
Ideal for Performance Alignment
A carefully chosen wheel alignment is only useful if the suspension can maintain those settings under load.
The MMX bushings help support geometry setups using:
- Increased negative camber
- Fast-road toe settings
- Track alignment
- Lower ride heights
- Wider tyres
This makes them particularly useful on professionally aligned performance builds.
Track-Day Benefits
On track, the front suspension is exposed to repeated high loads.
Hard braking, high lateral grip and kerb use all increase the forces acting through the control arm bushes.
The MMX spherical bushings can help provide:
- More repeatable steering response
- More consistent geometry
- Improved braking confidence
- Better tyre management
- Greater chassis precision
This makes them particularly well suited to track-day and clubsport-style F2X/F3X builds.
Installation Requires a Press
The factory rubber bushings must be removed and the MMX spherical assemblies pressed into position.
A hydraulic or fly press is required for installation.
Professional fitting is strongly recommended.
3D-Printed Press Tool Included
MMX includes a dedicated 3D-printed press tool with the kit.
This helps protect the spherical bearing during installation and reduces the risk of damaging the assembly while it is being pressed into the control arm.
Correct installation technique remains essential.
Four-Wheel Alignment Recommended
A full alignment should be carried out after replacing the control arm bushings.
Important settings to check include:
- Front toe
- Front camber where adjustable
- Steering wheel alignment
- Rear geometry
For track-focused cars, this is also an ideal opportunity to set the complete chassis around the intended use.
BMW F20 / F21 M135i
The MMX Front Control Arm Upgrade Bushings are compatible with the N55-powered BMW F20 and F21 M135i.
For tuned or fast-road M135i builds, they help reduce front-end compliance and sharpen steering response.
BMW F20 / F21 M140i
The B58-powered BMW F20 and F21 M140i are also supported.
These bushings are particularly useful on M140i models running upgraded suspension, tyres or aggressive geometry settings.
BMW F22 / F23 M235i
The MMX bushings are compatible with the BMW F22 M235i Coupe and F23 M235i Convertible.
They provide a more precise front suspension connection than the factory rubber components.
BMW F22 / F23 M240i
The BMW F22 M240i Coupe and F23 M240i Convertible are also supported.
For fast-road and track-focused M240i builds, the spherical bushings help improve front-end consistency under load.
BMW F30 / F31 335i
The MMX bushings are compatible with BMW F30 and F31 335i models.
They provide the same reduction in deflection and improved steering precision as on the F2X applications.
BMW F30 / F31 340i
The B58-powered BMW 340i is also supported.
For tuned or suspension-modified 340i builds, the upgrade helps provide a more direct and predictable front axle.
BMW F32 / F33 / F36 435i
The MMX Front Control Arm Upgrade Bushings are suitable for compatible BMW 435i models across the F32, F33 and F36 chassis.
BMW F32 / F33 / F36 440i
The B58-powered BMW 440i is also compatible.
The bushings are especially useful on cars running performance alignment, lowered suspension or higher-grip tyres.
Compatibility
Designed for applicable BMW F2X and F3X models including:
- BMW F20 M135i
- BMW F21 M135i
- BMW F20 M140i
- BMW F21 M140i
- BMW F22 M235i
- BMW F23 M235i Convertible
- BMW F22 M240i
- BMW F23 M240i Convertible
- BMW F30 / F31 335i
- BMW F30 / F31 340i
- BMW F32 / F33 / F36 435i
- BMW F32 / F33 / F36 440i
Engines include:
- BMW N55
- BMW B58
MMX officially lists the primary F2X fitment as F20, F21, F22 and F23 M135i, M140i, M235i and M240i, while the same product is also listed across its F3X range.
Please confirm exact vehicle specification before ordering.
What's Included?
The MMX Front Control Arm Upgrade Bushing Kit includes:
- 2x MMX spherical control arm bushing assemblies
- Anodised 7075 aluminium housings
- Stainless-steel spacers
- High-strength spherical bearings
- 3D-printed installation press tool
Supplied as a pair.
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