Ultra Racing BMW F-Series Underbody/Underfloor Brace – Mid Lower Chassis Stiffener, Centre/Center Tunnel Bar, Lower Crossmember/Subframe Connector – 1/2/3 Series F20 F21 F22 F23 F87 F30 F31 F34 F80 – Fits M135i M140i M235i M240i 335i 340i M3

Ultra Racing Underfloor Stiffening Bar for BMW F-Series

Unlock sharper handling and rock-solid stability on your BMW with this Ultra Racing underfloor reinforcement. This centre tunnel tie bar links key underbody points to increase torsional rigidity, enhance steering precision and deliver a calmer, more planted feel at speed. If you are searching for a lower crossmember brace, centre tunnel bar, subframe connector or chassis stiffener for BMW F-series, this is the upgrade that delivers.

We run this on our own builds and customer cars and the feedback is consistent: crisper turn-in, better composure over rough tarmac and more confidence through quick direction changes. By bracing the middle of the shell, it helps the suspension do its job, improving front to rear balance and consistency in fast road and track use.

Key benefits

• Boosts chassis rigidity for a more connected, confidence-inspiring drive
• Improves steering accuracy and cornering stability
• Helps maintain geometry under load for predictable responses
• Ideal for spirited driving, B-road blasts and track days
• Direct bolt-on using factory locations, 2-point layout
• Typically reuses original fixings unless hardware is supplied

Technical notes

• Mounting points: 2
• Fits to OE holes for a clean, reversible install
• Reinforces the centre section of the underbody to limit flex

Vehicle compatibility

BMW F-Series platforms and models:

• BMW 1 Series F20 F21 including M135i and M140i
• BMW 2 Series F22 F23 F87 including M235i and M240i
• BMW 3 Series F30 F31 F34 F80 including 335i and 340i and M3

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How it improves stability

Before: On bumpy surfaces the central shell can twist as load shifts between axles, reducing grip and feedback.	After: The Ultra Racing stiffening bar helps stabilise weight transfer and limits deformation for cleaner, more consistent responses.

Why enthusiasts choose this upgrade

• Noticeable improvement in body control without affecting comfort
• Pairs perfectly with performance springs, dampers and tyres
• A smart first step before big suspension changes
• Trusted by our team and highly rated by customers

Fitting and support

Professional installation available at MJ Modifications in Warwickshire. For a fitting quote or any questions, email info@mjmodifications.co.uk.