IronBox BMW E36 / E46 Spherical Rear Trailing Arm Bushings — RTAB Kit

These IronBox spherical-bearing bushings replace the OEM rubber rear trailing arm bushings used in BMW E36 and E46 rear suspension systems

They install in the original RTAB position shown as item 4 in the BMW rear suspension diagram

Replacing the flexible rubber bushings with spherical bearings removes unwanted elastic movement and provides a more rigid connection between the rear trailing arms and body mounts

This helps maintain more consistent rear suspension geometry under acceleration, braking and cornering loads and provides more precise rear-axle behaviour in drift, track and performance applications
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Main features
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• OEM RTAB replacement — installs instead of the original rubber rear trailing arm bushings
• High-load spherical bearings — designed for increased suspension loads and motorsport use
• Reduced bushing deflection — limits unwanted movement of the rear trailing arms under load
• Consistent suspension geometry — supports more stable rear toe and wheel positioning during acceleration, braking and cornering
• Increased rear suspension rigidity — provides a more direct connection than OEM rubber bushings
• 2024-T4 duralumin housings — lightweight bearing housings with an anodized surface finish
• Blacknitride-coated steel spacers — steel spacer sleeves with corrosion-resistant surface treatment
• Complete rear-axle set — includes two bearing housings and four spacer sleeves

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Compatibility
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• BMW 3 Series E36 Sedan
• BMW 3 Series E36 Coupe
• BMW 3 Series E36 Touring
• BMW 3 Series E36 Convertible
• BMW E36 M3
• BMW 3 Series E46 Sedan
• BMW 3 Series E46 Coupe
• BMW 3 Series E46 Touring
• BMW 3 Series E46 Convertible
• BMW E46 M3
• BMW E46 Compact only after confirming the original RTAB position and dimensions

Designed for vehicles using the standard BMW E36 or E46 rear trailing-arm bushing arrangement
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Not compatible with
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• BMW E36 Compact with E30-type rear suspension
• BMW E30

Other BMW suspension configurations unless compatibility is confirmed before ordering

Applications that use a different trailing-arm bushing diameter, width or mounting arrangement
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Kit includes
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• Anodized 2024-T4 duralumin housing with spherical bearing — 2 pcs
• Blacknitride-coated steel spacer sleeves — 4 pcs

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Street-use consideration
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Spherical bearings create a more direct suspension connection than OEM rubber bushings

This can increase the transmission of noise, vibration and road harshness into the vehicle body

The kit is primarily intended for drift, track, competition and performance-oriented vehicles where suspension precision is prioritised over factory comfort
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Important installation information
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Confirm the original rear trailing-arm bushing dimensions and suspension configuration before ordering

Inspect the trailing arms, RTAB brackets and chassis mounting areas for cracks, deformation and corrosion before installation

Remove the original rubber bushings using the correct press or extraction equipment

Do not transmit installation force through the spherical bearing itself

Install all spacer sleeves in the correct positions and confirm free bearing articulation before final assembly

All fasteners must be tightened according to the applicable BMW workshop procedure

A complete rear-wheel alignment must be performed after installation

Installation must be carried out by a qualified suspension or motorsport specialist