MMR Rear Underbody Chassis Brace (Tunnel Brace) for MINI F56/F55/F54 (2013+) Billet T-6061 Aluminium, Gloss Black Anodised Bolt-On Handling Upgrade, Improves Exhaust Clearance Cooper, Cooper S, Cooper SD, JCW

Rear lower floor brace for MINI F56, F55, F54

Transform the way your Gen 3 MINI steers and corners with this MMR rear lower floor reinforcement bar. CNC machined from billet T-6061 aluminium and finished in a deep black anodised coating, it replaces the bulky factory steel piece with a lighter, stronger stiffening bar that boosts torsional rigidity and creates vital space around the exhaust path for larger diameter systems.

Designed as a true bolt-on upgrade using the original mounting points, installation is straightforward with no cutting or drilling. Weight is reduced without sacrificing strength, and in day-to-day driving there is no noticeable increase in cabin noise, vibration or harshness. It is a beautifully engineered under-car brace that looks as good as it performs.

Key benefits

• Sharper steering feel and faster turn-in for B-road and track use
• Increased chassis stiffness for a more planted rear end and improved stability
• Extra clearance for performance exhausts and big bore pipework
• Lightweight aluminium construction compared with the heavy OE steel part
• Durable black anodised finish that resists corrosion and road grime
• Direct fit on factory bolt holes with new hardware supplied
• Reversible installation that keeps the car easily returnable to stock

Why we rate it

We have fitted this brace on our own builds and for customers, and the feedback is consistently positive. The rear of the car feels tighter and more predictable, cornering is flatter, and the steering response is more immediate. The quality of the machining and finish is superb, and it integrates perfectly with fast road or track-day setups.

Vehicle compatibility

• MINI F56 3-door hatch 2013 onwards
• MINI F55 5-door 2013 onwards
• MINI F54 Clubman 2015 onwards
• Models: One, Cooper, Cooper S, Cooper SD, John Cooper Works
• Petrol and diesel engines

What is included

• MMR rear lower floor brace in billet T-6061 aluminium
• Black anodised finish
• New installation hardware

Installation and support

Professional fitting available at MJ Modifications in Warwickshire. Email info@mjmodifications.co.uk for a quotation and booking.

Complete your chassis package

For the best overall balance, pair this rear lower brace with the matching centre and front underfloor bracing options. Each piece is available separately to build out a comprehensive rigidity kit for your F-series MINI.

Search-friendly terms

MINI F56 rear lower brace, MINI F55 floor brace, MINI F54 Clubman rear brace bar, chassis stiffener, rear subframe brace, underfloor reinforcement, rear rigidity bar, performance handling upgrade, fast road brace, track day chassis brace, aluminium brace black anodised, bolt-on rear brace, MINI Gen 3 body bracing, steering response upgrade, exhaust clearance brace.