The IronBox rear suspension conversion kit is a purpose-built drift suspension system developed for BMW E30 and BMW E36 Compact chassis ⠀ The complete suspension geometry has been redesigned to provide more consistent tire contact with the road surface throughout suspension movement ⠀ Unlike the original semi-trailing-arm suspension, the IronBox system provides independent adjustment of rear camber, toe, and upright angle, allowing the rear axle geometry to be configured for the required drift setup ⠀ The system uses spherical bearings at all moving suspension joints and a rigid connection between the rear subframe and chassis for precise and predictable suspension response ⠀ Main features ⠀
Purpose-built drift suspension geometry — redesigned suspension kinematics help maintain a more consistent tire contact patch
Adjustable rear camber — allows the wheel angle to be configured for the required grip and tire-wear characteristics
Adjustable rear toe — provides control over rear axle stability, rotation, and response
Adjustable upright angle — provides an additional geometry setting unavailable with the original suspension
Six adjustable suspension links — allow precise configuration of the complete rear suspension geometry
Spherical-bearing joints — eliminate the compliance associated with conventional rubber suspension bushings
Rigid subframe mounting — creates a direct connection between the rear subframe and chassis
5×120 wheel bolt pattern — used with the required compatible BMW E60 wheel hubs
Dual-caliper provisions — allows two rear brake calipers to be installed on each side for separate main-brake and hydraulic handbrake circuits
Designed for up to 400 hp — when used with the specified compatible BMW E60 2.5- or 3.0-liter diesel differential, axles, and wheel hubs
Aluminum-alloy and steel construction — combines strength, rigidity, and controlled component weight
Powder-coated and anodized components — provide corrosion protection and a durable finish
BlackNitride-treated adjusters, locknuts, and spacer sleeves — provide additional surface protection for the steel adjustment components
⠀ Compatibility ⠀
BMW 3 Series E30
BMW 3 Series E36 Compact
Dedicated drift and motorsport project vehicles ⠀ Not compatible with conventional BMW E36 Sedan, Coupe, Touring, or Cabriolet rear suspension ⠀ Compatibility with BMW E30 M3, BMW Z3, modified chassis, roll cages, fuel systems, exhaust systems, and other custom vehicle configurations must be confirmed before ordering ⠀ This is not a direct bolt-on suspension kit ⠀ Installation requires welding the supplied rear subframe mounting insert into the vehicle ⠀ The kit must be used exclusively with integrated rear coilovers where the spring is installed around the damper ⠀ The original separate rear spring and shock absorber arrangement cannot be retained ⠀ Required parts — not included ⠀
Compatible BMW E60 2.5- or 3.0-liter diesel differential
Matching BMW E60 drive axles
Matching BMW E60 wheel hubs
Compatible integrated rear coilovers
Brake discs and brake calipers
Hydraulic handbrake components and brake lines if a dual-caliper setup is used
⠀ The exact BMW E60 donor components, part numbers, differential type, final-drive ratio, axle configuration, wheel bearings, brake components, and ABS configuration must be confirmed before purchasing the required parts ⠀ Kit includes ⠀
Rear subframe — 1 pc
Main suspension arms — 2 pcs
Rear uprights — 2 pcs
Adjustable suspension links — 6 pcs
Weld-in rear subframe mounting insert — 1 pc
Spherical-bearing joints integrated into the moving suspension connections
⠀ Important brake information ⠀ The suspension provides mounting provisions for two rear brake calipers on each side ⠀ Brake discs, primary calipers, secondary hydraulic handbrake calipers, brake lines, fittings, hydraulic handbrake, and brake fluid are not included ⠀ The required caliper and brake-disc configuration must be confirmed according to the selected BMW E60 wheel hubs and rear uprights ⠀ Do not assume compatibility with any brake or ABS components unless the complete configuration has been confirmed ⠀ Important installation information ⠀ Professional fabrication and welding are required ⠀ The chassis must be measured and inspected before installation to confirm that the original mounting points and body geometry are undamaged ⠀ The weld-in subframe mounting insert must be positioned accurately before final welding ⠀ The complete suspension must be checked through its full range of compression, droop, and wheel movement ⠀ All spherical bearings, adjustable links, locknuts, mounting points, brake hoses, drive axles, wheels, and tires must have sufficient clearance throughout the complete suspension range ⠀ A complete wheel alignment and suspension setup are required after installation ⠀ Corner weighting is strongly recommended for competition vehicles ⠀ All spherical bearings, fasteners, adjusters, and welded mounting points must be inspected regularly during motorsport use ⠀ Installation, welding, suspension setup, brake configuration, and final inspection must be carried out by qualified motorsport specialists