Quaife ATB limited slip differential for BMW and Mercedes
The famous Quaife ATB limited slip differential is one of the world's most popular performance upgrades for BMW and Mercedes cars.
This unique device absolutely transforms the way your car applies power to the road, offering a stunning increase in traction, acceleration, cornering speeds and overall handling. Unmatched in its popularity, the Quaife design will work flawlessly with all OE components, will not void your manufacturer's warranty, and comes with its own unique worldwide lifetime guarantee.
We have created the world's largest list of BMW and Mercedes aftermarket LSD applications based around the Quaife, to view it click here and use the filter to narrow your search. If you do not see a Quaife listed for your model, it's still very likely that we will have one available, so please don't hesitate to enquire.
Bring your car to life.
Watch Chris Harris of Autocar demonstrate the advantages of a Quaife in our BMW 335i demo
As a replacement for the standard factory open diff, the Quaife ATB limited slip differential is a clever device that vastly improves the performance of any BMW or Mercedes by how it applies power to the road.
The problem with the standard open diff is that it can only ever apply the same amount of torque to both driving wheels, so when a wheel slips, it will only put through the amount of torque it requires to power that spinning wheel (i.e. very little!). This results in almost a complete loss of drive to both wheels. This frequently occurs in high-powered cars, especially in low traction conditions such as rain and snow.
The unique Quaife uses sets of floating helical cut gear pinions that run in pockets and mesh during normal driving, so to act as a standard diff. Should one of the driven wheels start to spin however, the helical gears start to generate a torque bias thanks to the axial and radial thrust of the helical gear pinions in their pockets. The result is a progressive transfer of torque away from the spinning wheel to the one with more traction, offering an enormous performance boost as well as increased handling. The car becomes easier to control, more fun to drive, and much more predictable for the driver. The Quaife is capable of varying the torque split from 0-80%, and does this quietly and smoothly in operation.
Learn more about Quaife themselves by watching the video below, or visit their website RT Quaife Engineering
Quaife vs the competition
ATB vs Locking 'clutch-plate' LSD
Quaife’s new patented ATB limited slip differentials were designed to overcome the flaws of the common locking ‘clutch-plate’ limited slip diff - offering an exciting and innovative way to transform your vehicle’s performance (while also saving you money!). This clever device has taken the BMW tuning world by storm, and we are beginning to see similar signs for Mercedes cars as we develop more and more applications. Here is why Quaife is the only option for your BMW or Mercedes:
Performance
The differences in performance gains between the locking LSD and ATB are generally minor, but the difference is in HOW they deliver the performance. The clutch-plate LSD operates using an internal spring pack and set of clutches that lock in order to drive the car in low traction conditions. This often causes abrupt locking of the rear axle, and if high locking percentages are used, can destabilise the vehicle making it unpredictable and difficult to control.
It’s true that sometimes these negative characteristics can be used beneficially in the hands of experienced drivers. Drifting, drag racing, and even circuit racing cars can achieve improved timed performance, if an unstable rear end can be utilised. But for us they are certainly not desirable characteristics for road cars. With that said, many race teams (including some participating in the BTCC) converted over to Quaife from clutch-plate LSDs because of “significant snap-oversteer out of slippery turns”. Again, this is attributed to the locking mechanism.
The Quaife ATB is said by our customers to be "intuitive". i.e. more predictable for the driver and easy to control. (Demonstrated well by Chris Harris in the above video!) These characteristics are attributed to the Quaife's unique and very clever internal gear design. It automatically biases the torque across the axle to a constantly varying degree depending on which wheel is enjoying the most grip. This results in optimum grip levels in an given instance, never locking or snapping, and ultimately giving the driver a more accurate control of the rear end.
EVO magazine agrees - "it allows you to bring the tail into play with the most minutely adjustable precision. It even makes the E46 M3, complete with locking M differential don't forget - feel like it lacks control."
One of our customers who was lucky enough to test both types of differential gave a good review on both types: here.
Read many more editorials and customer testimonials in the library section of our website.
Design
Employing a clutch-plate locking LSD can be a costly investment. The wearing of the clutches means the unit will eventually need replacing, and it is not uncommon for them to reach their useful life as low as 30,000 miles. Special lubricants and lubricant changes are also required. Due to their finite life, they cannot be guaranteed for more than 12 months!
This is Quaife’s biggest advantage. Its non-wearing internal gears are designed for the life of the car, with no maintenance or special lubrications required. The Quaife is essentially a plug and play device, and is backed by a unique worldwide lifetime warranty!
Quaife vs other "geared" differentials?
Do not be fooled by imitations.
Other geared differentials on the market are either replicas, or modified versions of the original Quaife ATB differential. We have even seen one former Quaife dealer introduce their own brand based on the Quaife design, but with added “special features”. In reality, these features offer no performance improvements for you, and we believe they were primarily implemented to avoid conflict with Quaife’s patent. It is not surprising to see that many of these units were direct copies, with internal measurements even down to the nearest 0.01mm. Despite unfounded claims of better quality (and yet cheaper price), these differentials fail to provide the true performance and engineering excellence of the patented Quaife ATB differential.
Do not settle with second best for your BMW or Mercedes.