IronBox BMW E36 / E46 / Z4 PRO Adjustable Rear Arm Kit — Coilover Only
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420.00
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This IronBox PRO rear suspension kit combines adjustable upper and lower control arms for precise rear-geometry setup on BMW E36, E46 and compatible Z4 applications
The four steel arms use spherical bearings to provide a rigid and precise suspension connection for drift, track and competition use
A ±15 mm adjustment range allows negative, zero and positive geometry settings with approximately ±3.5 degrees of available angular adjustment
The upper arms are compatible with the standard rear anti-roll bar and provide multiple mounting positions for adjusting its effective stiffness
This kit must be used with integrated true rear coilovers and is not compatible with the original separate rear spring configuration ⠀ Main features ⠀
Complete four-arm PRO set — includes adjustable upper and lower arms for both sides of the rear suspension
±15 mm adjustment range — allows the arm length to be shortened or extended according to the required geometry
Approximately ±3.5-degree adjustment — supports negative, zero and positive suspension-angle configurations
Spherical-bearing construction — reduces unwanted compliance under high rear suspension loads
Adjustable anti-roll-bar mounting — multiple positions on the upper arms allow changes to the effective stabilizer stiffness
Standard anti-roll-bar compatibility — designed to retain the corresponding factory rear stabilizer arrangement
True coilover configuration — intended for integrated rear coilovers with the spring positioned on the damper
Steel construction — developed for demanding drift, track and motorsport applications
Powder-coated arm bodies — provide a durable protective finish
Blacknitride-treated components — adjusters, lock nuts and spacer sleeves receive an anticorrosion surface treatment
⠀ Compatibility ⠀
BMW 3 Series E36 with standard multi-link rear suspension
BMW E36 M3 after confirming the rear suspension and anti-roll-bar configuration
BMW 3 Series E46
BMW E46 Compact after confirming the rear suspension configuration
BMW E46 M3 after confirming the rear suspension and anti-roll-bar configuration
BMW Z4 E85 and E86 after confirming the exact model and mounting configuration
BMW E36 or E46 vehicles with mixed M and non-M rear suspension components
BMW Z4 and Z4M variants
Aftermarket anti-roll bars and non-standard stabilizer links
Rear suspension conversions using modified subframes, hubs or mounting points ⠀ Not compatible with ⠀
BMW E36 Compact
OEM-style rear suspension with a separate spring and damper
Coilover kits that retain the original separate rear spring position
Applications requiring the upper control arm to retain the factory spring seat
Other BMW chassis unless compatibility is separately confirmed ⠀ Kit includes ⠀
Adjustable rear upper control arm — 2 pcs
Adjustable rear lower control arm — 2 pcs
Integrated spherical bearings
Blacknitride-treated adjusters, lock nuts and spacer sleeves
Exact mounting hardware is not separately listed by IronBox and should not be assumed to be included
⠀ Street-use consideration ⠀ Spherical bearings provide a more direct suspension connection and may transmit more noise, vibration and road harshness than original rubber-bushed arms
This PRO kit is intended primarily for drift, track and competition-oriented vehicles where geometry range, rigidity and suspension precision are prioritised over factory comfort ⠀ Important coilover information ⠀ This kit removes the original upper-arm spring-support function and therefore requires true rear coilovers with the spring integrated around the rear damper
A conventional rear coilover kit that still uses a separate spring in the original location is not compatible
The rear damper towers and mounting points must be suitable for carrying the additional spring load created by a true coilover conversion
Inspect and reinforce the rear shock-tower areas where required before transferring the complete vehicle weight and suspension load through the coilovers ⠀ Important installation information ⠀ Confirm the exact rear suspension, coilover and anti-roll-bar configuration before ordering
Compare the initial length and mounting orientation of every new arm with the corresponding original component
Maintain sufficient thread engagement throughout the complete adjustment range
Do not operate the vehicle with insufficiently engaged adjustment threads or loose lock nuts
Select matching anti-roll-bar mounting positions on the left and right upper arms
Check wheel, tyre, driveshaft, brake-line, stabilizer and body clearance through the complete suspension travel
All spherical bearings and mounting components must move freely without binding
All fasteners and adjustment-locking components must be correctly tightened before use
A complete professional rear-wheel alignment is required after installation
Installation must be performed by a qualified suspension or motorsport specialist