I enjoy using the Porsche configurator to create my “fairly reasonable Porsche dream car” for fun. While purchasing a GT3 is out of the question for me financially, I can still achieve some of the performance without the high cost. Only performance-related options, such rear-axle steering, PASM, PDCC, and Sport Chrono, would be available on my ideal car.
In 2013, the 918 Spyder became the first car to feature active rear-axle steering. Before it was made available on the 991.1 GT3, we had to wait a few years. Since this technology has been in use for ten years, you no longer need to buy a supercar or GT3 to benefit from it. That option is available for a 911 Carrera S. Yes, the incredibly powerful option only raises the price of a new 911 Carrera S by $2,090. This may be old news to some, but I believe it is important to reiterate for those who have recently joined the Porsche community or who want to do so.
It’s no secret that the 911 has grown broader and longer as it has become a vehicle with ever-improving performance. Porsche used a lot of what it learnt from its racing program to its street cars. Cars that are longer and wider are more stable at high speeds. The 911 did, however, lose some of its lower-speed agility as the wheelbase extended. On a race car, this is altered by an aggressive alignment and the driver’s capacity to turn the vehicle simply by adjusting the throttle. Rear-axle steering is a convenient option for those of us who are not experts.
In order to boost stability, the rear wheels of this depiction of a G2 Panamera turn in the same direction as the front wheels (to the left) at greater speeds. To promote agility, the rear wheels rotate at slower rates in the opposite direction from the front wheels (right).
It has a clever but relatively basic mechanism. The rear wheels will steer in the opposite direction from the front wheels at speeds of 31 mph or less. The wheelbase is shortened as a result. Your 992 will feel more nimble at low speeds, similar to an older 911.
Over 50 mph causes the back tires to steer in the same direction as the fronts, extending the wheelbase rather than decreasing it. This results in even greater stability when cornering at high speeds.
Rear-axle steering is an option for the 992 Carrera range (seen in the top photo). The rear-steer system of the 992 is seen above.
Imagine getting the best of both worlds in this situation. The high speed steadiness of more recent models combined with all the low-speed agility of, example, an early 911. Now, compared to the front tires, the rear tires will only turn marginally. However, this is sufficient to shorten turning distances and even facilitate parallel parking.
Therefore, a vehicle with rear axle steering will undoubtedly improve your driving experience, whether you are constructing your own Porsche dream car or simply looking for a pre-owned model.
In This Article...
Dee
Undoubtedly, despite being a large vehicle, it is excellent at turning.
However, because it’s a Porsche, I had higher hopes because I believe the vehicle has excessive bump steer.
I’m used to driving (RWD) sports cars, so this is what really struck out to me.
It drives quite well aside from that, but I wouldn’t choose it the next time (also due to the extra weight).
dgrounds
Rear Wheel Steering would have been requested even if the Performance Package in my 4S build configuration didn’t have it. The turning radius differs significantly as a result. I’m overjoyed that it’s in my automobile. Highly advised.
Absolutely agree! On our 4S, we ordered the rear axle steering, and I adore it. The car turns with a small turning circle and feels great in small settings. I’ve never experienced something like that. Amazing.
better stability when changing lanes, more agility around bends: a rear axle for steering
Active rear-axle steering is a function that can be added to any 911 or Panamera model, or depending on the specific model, is already included as standard equipment. The two- and four-door sports cars with rear-axle steering are far more agile when navigating through tight turns, more stable while changing lanes at high speeds, and simpler to control in city traffic. The front and rear wheels will turn in the opposite direction if the driver enters a corner at less than about 50 km/h. This effectively reduces the wheelbase, making it possible to maneuver the sports vehicle more easily and with smaller steering movements around the turn. When it comes to maneuverability, a 911 with rear-axle steering also drives like a tiny car because the turning circle is cut in half to 10.7 meters. However, it’s a different situation when changing lanes abruptly when traveling at high speeds. In such cases, the wheelbase essentially extends and the front and rear wheels steer in the same direction. As a result, the vehicle is more stable, and the quicker development of lateral force at the rear axle enables more spontaneous and seamless direction changes. But it’s not just that: Utilizing rear-axle steering results in a front-axle steering ratio that is significantly more direct and a competitively unmatched steering experience.
Rear-axle steering explained through technology
Porsche originally tested passive steering of the rear wheels on the 928, which is also the vehicle that saw the development of the innovative toe-compensation “Weissach steering” suspension system.
However, a complete active rear-wheel steering system didn’t appear on a Zuffenhausen sports car until the 918 Spyder’s debut last year. The 991 GT3 and Turbo have now received the system as well.
The 911 has a tendency to understeer as a result of its rear-engined configuration because there is less weight on the front wheels. The 991 generation attempts to address this by lengthening the wheelbase (more than the body), which effectively transfers more weight to the front wheels than the 997 generation did.
But this has brought about its own issue. The car’s handling responsiveness decreases as the wheelbase lengthens.
The rear-axle steering system enters the picture here. The rear wheels can be guided up to 2.8 degrees in the opposite direction of the front wheels at speeds under 50kph (31mph).
By effectively shortening the car’s wheelbase, this improves its maneuverability at slow speeds. In contrast, 45 degrees of steering lock would be equivalent to 2.8 degrees of wheel turn on the front wheels.
The rear-axle steering turns the back wheels up to 1.5 degrees in the same direction as the front wheels when the vehicle is moving at speeds greater than 80kph (50mph). By effectively lengthening the wheelbase, this improves cornering stability for fast cars.
But it also speeds up the loading of the rear wheels, which enhances the steering response of the 991 GT3 and Turbo.
Two electromechanical actuators, located immediately in front of the upper wishbone on either side of the chassis, are used throughout the entire system. The tops of the back uprights are where the steering arms attach.
Before transmitting a signal that causes electrical motors to either “push” or “pull” the steering arms in order to achieve the necessary angle and direction of rear-wheel steering, the actuators are connected to the car’s ECU, which measures road speed and steering angle.
The best approach to brush up on Porsche’s increasingly sophisticated engineering is to use our online “technology explained” features. View them all here.
In which Porsches is rear-wheel steering available?
911 GT3 Porsche Porsche first installed an active rear steering system in the 918 Spyder, but the first reasonably priced variant was the 911 GT3 from the 991 period.
Are there rear wheels on the Porsche GT3?
Active rear steering on the 991 GT3 is demonstrated. The car’s effective wheelbase is reduced by the rear wheels counter steering up to 50 kph, making it more agile. The wheels steer in the same direction at speeds more than 80 kph to increase stability.
What benefit does rear-wheel steering offer?
As was already established, compared to front wheel steering systems, rear wheel steering can offer a smaller, sharper angle of rotation. Forklift trucks might benefit from rear wheel drive alternatives because they do not need to travel at high speeds. Similar to that, rear wheel drive is frequently used in motorsports.
Better steering with four wheels?
Over the past few decades, all-wheel steering has been an option in a wide range of vehicles of all types and sizes, from the GMC Sierra to the Honda Prelude. Although the idea of four-wheel steering in automobiles is not new, it has gained popularity recently.
The usage of four-wheel steering technology is advantageous since it speeds up steering response time and aids in maintaining vehicle stability at higher speeds. With this technology, steering is done by all four wheels rather than just the front two, providing previously unheard-of control and mobility. Despite this, it takes some getting acclimated to 4 wheel steering.
A Master Mechanic was contacted to discuss the primary benefits and drawbacks of a four-wheel steering system.