BMW M140i/M240i Quaife ATB Helical LSD - Rear Differential Insert (Diff Only) - B58 RWD F20 F21 F22 F23 - 1 Series/2 Series Limited Slip Diff Upgrade - Torque Biasing Gear Type - Open Diff Replacement - M Performance Diff Alternative

Quaife ATB Helical Gear Diff Upgrade for BMW M140i and BMW M240i - Diff Only - Rear Axle Insert

Unlock the real potential of your B58-powered BMW with the Quaife automatic torque biasing helical gear centre. This rear axle upgrade replaces the stock open unit inside your existing casing, delivering game-changing traction, sharper cornering and faster drive off bends. Perfect for enthusiastic road use, track days and drag launches, this is the proven drivetrain enhancement for F20 F21 M140i and F22 F23 M240i owners who want grip without compromise.

What you will feel

• Big increase in grip at the rear wheels for confident acceleration
• Reduces inside wheelspin on corner exit for cleaner, quicker launches
• Predictable handling in wet and dry conditions with improved stability under power
• Refined road manners, quiet operation and OEM-level drivability
• No clutch packs to wear out, no routine servicing, no special attention required
• Works in harmony with factory ABS, DSC and traction systems
• Designed and manufactured in the UK with a lifetime warranty

Why a Quaife ATB makes such a difference

The ATB uses precision helical gears to automatically send torque to the tyre with more available grip. Unlike plate-style units, there are no friction discs to service and no noise or chatter. The result is stronger drive off apexes, better turn-in balance and more consistent performance on B-roads, circuits and drag strips. It is a fit-and-forget solution that feels factory fresh yet delivers serious traction gains.

Real results from real cars

We run these units on our own builds and customer vehicles, and the feedback is consistently positive. Expect more confidence in poor weather, better composure when powering out of tight bends and noticeably quicker progress on fast road drives. It is the rear axle upgrade we recommend for M140i and M240i owners who want dependable grip without adding harshness.

Fitment and compatibility

Suits BMW M140i and BMW M240i with the B58 engine on the F-series platform:

• F20 F21 M140i rear-wheel drive
• F22 F23 M240i rear-wheel drive

Unsure about your build or differential type? Contact us and we will confirm fitment for your VIN.

What is included

• Diff only - Quaife ATB helical gear centre to install in your existing housing

Professional installation is recommended.

Installation service

MJ Modifications offers supply and fitting in Warwickshire with careful setup and road testing. Request a fitting quote at info@mjmodifications.co.uk.

Search-friendly terms our customers use

• M140i diff upgrade F20 F21
• M240i rear axle LSD F22 F23
• B58 torque biasing differential
• BMW 1 Series performance differential
• BMW 2 Series helical diff insert
• Open diff replacement for M140i
• Gear type LSD for BMW B58
• Final drive upgrade for track day and fast road
• Quaife ATB centre for M240i
• M Performance diff alternative for F-series

Fit a Quaife ATB to your M140i or M240i and turn power into forward motion with grip you can trust. Drive harder, earlier and more confidently, every day.