Rear wheel steering systems have been used in cars for decades, with Mazda making itself one of the pioneers of the technology by showcasing it in the 1984 MX-02 concept car. Since then it has been used in a number of models, including the Honda Prelude and Nissan Skyline R34 GTR, but in recent years it has become more popular.
Rear wheel steering systems are still not widespread though, and usually only found on high-end cars and costing extra to add. So how does it work, and which cars can you buy with it fitted today?
Sometimes called all wheel steering systems, or four wheel steering systems, it quite simply means the back wheels on the car can also turn to assist the front wheels. The back wheels only need to turn a tiny amount - usually no more than five degrees - to make a big difference to how the car behaves. Rear wheel steering systems perform two functions and do them in different ways.
At slow speeds, the rear wheels turn in the opposite direction to the front wheels just a fraction, which sharpens the speed and angle at which the car turns. This makes parking and slow speed manoeuvres much easier, as it t effectively shortens a car’s wheelbase. Most rear wheel steer systems turn the back wheels in the opposite direction to the front at speeds below 30-40mph.
However, at high speeds the rear wheels turn in the same direction as the front wheels, which makes changing direction much more stable as well as smoother, as it reduces the amount of angle needed on the wheels while rotating (the yaw) to make the turn. Below we look at eight cars you can buy today which feature rear wheel steering systems.
The A6 is a big car, so rear wheel steering is a huge benefit, especially when tackling tight car parks. Audi’s optional dynamic all wheel steering system effectively shortens the car’s wheelbase by around a metre at slow speeds. Also, coupled with Audi’s Quattro all-wheel drive system it increases high speed stability.
BMW’s chauffeur car and five star hotel on wheels has the option of being fitted with BMW’s Integral Active Steering system for £1,195 extra. At speeds under 37mph the back wheels turn against the front to increase manoeuvrability, but the system can also help stabilise the car in critical situations before the driver has had time to take evasive action.
The 812 Superfast was the first Ferrari to feature electric power steering, and it comes with the second version of Ferrari’s Virtual Short Wheelbase system, which was first used on the F12tdf. With a 0-62mph of just 2.9 seconds we’re sure any owners of the 812 Superfast are grateful for any high speed stability assistance they can get.
Lamborghini’s SUV uses an all-wheel steer system which is derived from technology used in the Aventador S supercar, and can turn the back wheels up to three degrees in either the opposite or same direction as the front wheels, depending on what speed the car is travelling and which drive mode it is in. In both cars the system works with the torque vectoring system to negate understeer and oversteer.
Lexus has been using rear wheel steering on a number of its models for a while now but it’s especially beneficial in the LC 500 Sport Plus, which is not only a powered by a thunderous 5-litre V8, but it’s wide too: so fast speed stability and low speed manoeuvrability are both vital. The car’s ECU constantly monitors driver inputs and speed to angle all four wheels the optimum amount.
Mercedes-AMG’s system can rotate the back wheels independently up to 1.5 degrees in either direction, sending them in the opposite direction to the front at speeds below 62mph. The same technology is also found in the GT C and GT 4-Door as standard.
Porsche’s optional rear axle steering system on its flagship SUV reduces the car’s turning circle from 12.1 metres to 11.5 metres by turning the back wheels up to three degrees in the opposite direction to the front wheels at slow speeds, while it turns them 1.5 degrees in line with the front wheels over 50mph for greater high speed stability.
Unlike the Cayenne, in the 911 GT3 RS Porsche’s rear wheel steer technology is focussed primarily on high speed corning accuracy and stability, what with the GT3 RS effectively being a road legal race car. The back wheels do still turn in the opposite direction as the front at slow speeds though, which should help keep owners from scuffing those gorgeous wheels.