MMX Billet Rear Subframe Inserts for BMW F2x/F3x (1/2/3/4 Series) CNC 6061-T6 Aluminium Handling Upgrade | Rear Subframe Bush Insert Kit | Fast Road & Track | UK Made

Rear Cradle Bush Insert Set for BMW F-Series 1 2 3 4 - Precision Machined Alloy Handling Upgrade

Transform rear-end composure and steering confidence with this UK-engineered rear axle carrier insert set for BMW F-series platforms. Precision CNC machined from 6061-T6 aluminium, these billet pieces occupy the voids in the four factory rubber mounts to control cradle movement under load, stabilise suspension geometry, and sharpen response during hard cornering, braking, and acceleration.

Ideal for drivers seeking a tight, connected feel without resorting to solid bushes, this bolt-on bush support kit delivers a more planted rear axle, reduced wheel hop, improved traction out of bends, and a more predictable chassis on spirited road drives and track days. We run these on our own builds and customer cars and the feedback is consistently glowing - a high-impact upgrade that keeps daily comfort intact.

Why this upgrade works

• OE rubber mounts allow the rear carrier to shift vertically and fore-aft under load, softening responses and blurring feedback
• Inserts act as precise void fillers to limit movement, helping the suspension and differential do their job consistently
• Maintains alignment control during transient inputs for cleaner turn-in, better mid-corner stability, and stronger traction on exit
• Enhances the effectiveness of performance springs, dampers, coilovers, and rear anti-roll bars

Key benefits

• CNC machined 6061-T6 alloy for strength, precision, and durability
• Rear cradle lockout style support without the harshness of solid mounts
• noticeable reduction in subframe shuffle, squat, and differential wind-up
• Helps curb wheel hop on launches and bumpy surfaces
• Retains road manners - minimal additional NVH reported by users
• Quick to install with the axle carrier in situ - fully reversible

Compatibility - BMW F-Series

Fits petrol and diesel, manual and automatic models across:

• F20 F21 - 1 Series
• F22 F23 - 2 Series
• F30 F31 F34 - 3 Series including Gran Turismo
• F32 F33 F36 - 4 Series including Gran Coupe

NVH - noise, vibration, harshness

Designed to control movement without turning the car into a race-only setup. Most owners report little to no extra cabin noise or vibration. NVH perception varies by vehicle and setup - ensure correct seating and torque to factory specifications for best results.

Installation and fitting

Typical install time is around 60 minutes with basic tools. No press required and completely reversible. For a professional fitment service, we recommend booking with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

What is included

A complete set of precision-machined aluminium inserts designed to occupy the voids in the four rear axle carrier rubber mounts on BMW F-series models listed above.

Who is this for

• Drivers who want a sharper, more confidence-inspiring rear end without going to solid bushings
• Fast-road and track-day enthusiasts looking for a high-value, bolt-on handling mod
• Owners chasing better stability under braking and stronger traction under power

Search-friendly terms customers use

BMW F20 F21 F22 F23 F30 F31 F32 F33 F34 F36 rear cradle bush kit, rear axle carrier insert set, aluminium bush supports, rear end stability upgrade, wheel hop fix, differential movement reduction, F-series chassis handling mod, billet alloy bush inserts, UK manufactured performance parts, geometry control under load, BMW 1 Series 2 Series 3 Series 4 Series rear bush upgrade.

Order today for a proven rear-end stability upgrade that tightens the chassis, boosts confidence, and keeps day-to-day refinement intact.