A little over forty years ago, the Porsche 928 revolutionized suspension technology—with the legendary Weissach axle.
The year is 1973. The first generation of the iconic 911 has been on the market for nine years. However, voices within the industry have been questioning the longevity of this rear-engine sports car due to new suspension designs that were gaining fast, just around the corner.
A succession plan was in place – the first Porsche with a front-engine, the Porsche 928, was being developed with its transmission located on the rear axle and connected to the engine via a longitudinal shaft in a rigid central tube for better weight distribution. Engineering history was rewritten in 1977 with the futuristically designed 928, especially with regard to its suspension.
Developed to mitigate the lift-off oversteer that was then common in most cars, the Weissach axle is a revolutionary suspension technology that is still the basis of every Porsche sports car on the road today and contributes to the driving dynamics that Porsche has become renowned for.
The birth of the Weissach axle
The early 928 prototypes suffered from unstable self-steering tendencies. Aggressive use of the accelerator would create shifts in the car’s centre of gravity, and the extra load on the wheels would cause them to point outward, inducing oversteer.
And so, Porsche’s Hans-Hermann Braess and Gebhard Ruf looked for ways to counteract this tendency by focusing on elasto-kinematic elements through rubber bushings between the axle components and the suspension. The goal was to keep the wheel pointing in when the accelerator is released.
Going deeper into the development, Porsche engineers Manfred Bantle and Walter Näher ran a peculiar experiment with future suspension components and a second steering wheel in the back seat of an Opel Admiral. Näher, who made slight changes from the back seat while Bantle drove, was able to stabilize the handling, but he had to be extremely quick to achieve the desired effect – 0.2 seconds to be exact.
This unconventional experiment eliminated oversteering and spearheaded modern axle kinematics.
Porsche test driver, Frank Lovis said “It didn’t make the car faster in curves, but it did make it much easier to handle.” After years of refinement, the fully developed Weissach Axle finally made its way into the Porsche 911 (993), handling both longitudinal and lateral forces.
Manfred Harrer, who was director of suspension development at Porsche at the time, found it hard to state the importance of the Weissach Axle, which marked a first for toe-compensating rear suspension in a product car during the time of its inception. The culmination of its angle-adjusting, self-stabilising and equalisation characteristics has made it one of the key contributing factors to how easy it is to handle a Porsche, for both urban driving and on the racetrack.
Development work continues, in part because the benefits of the Weissach axle are constantly being adapted to nearly every modern sportscar and more compact installation spaces, including our 4 door vehicles like the fully electric sports car of the future as well as the current generations of the Panamera, Cayenne and Macan. Complemented by new technological milestones already in sight, our modern day Porsche cars like the Macan is more agile, stable and drivable.
A compact SUV that inextricably combines sportiness, design and everyday practicality, the Porsche Macan remains a true sports car at heart. Experience and discover the world of Porsche today.