Rear brake caliper adapters for G20 G21 G28

The TRONIK Rear Big Brake Upgrade for BMW 3 Series G-Chassis is a precision-engineered braking solution designed to support the installation of OEM BMW M3 G80 and M4 G82 rear brake calipers together with 370×24 mm rear brake discs. This rear brake conversion is ideal for drivers looking to upgrade their factory BMW braking system with genuine M-performance components. This rear big brake upgrade kit significantly improves thermal capacity, braking efficiency, and rear axle stability under high-load conditions. The increased disc size and M-caliper configuration provide consistent braking performance for spirited street driving, performance builds, and track-focused applications. The system uses CNC-machined steel adapter brackets, engineered to maintain correct OEM brake geometry, caliper alignment, and disc centering. Adapters feature a galvanic anti-corrosion coating for long-term durability and are supplied with high-grade mounting bolts and spacers, ensuring a secure and precise installation.