Rear Wheel Drive Makes City Parking a Pickup Possibility

Pickups and light trucks are great. They’re fun, they make a statement and you can throw your whole life in the back of them. You can run them over dirt tracks and even through river beds (probably not in the light truck). The one thing they’re not that known for is their maneuverability in the city. But they soon will be.

German parts supplier ZF has recently fitted their pioneering new system to a Ford F-150, America’s most popular new car. Their new innovation – a rear-wheel steering system. With the system off, the truck performs much as you would expect, requiring multiple turns to fit into a European standard parking spot.

With the system turned on, the wheels turned more than 12 degrees in the opposite direction, radically improving the pickup’s maneuverability. Despite the benefits of the rear wheel drive, it did nothing bad to the F-150’s electric steering system. In fact, now that steering systems are mainly electric rather than hydraulic, the system is much cheaper and reliable to produce. It’s also a lot easier to fine tune to the idiosyncrasies of steering systems in different models.

If there are elements of the automobile that are still hydraulic, then ZFs system seems to be adaptable. In the test they used steering knuckles from Quadrasteer trucks to make their Active Kinematics Control work with the Ford F-150’s simple live rear axle. Don’t worry, they didn’t use anything else from the overpriced system.  For a vehicle with a solid rear axle, the system requires an additional steering axle and electronic controller (as well as the ball joints). However, it only uses energy when the steering wheel is turned.

ZF has been supplying Porsche and other manufacturers with the system since 2013 – but this is the first time they have adapted it for a pickup. The Active Kinematics Control uses a pair of electrically driven actuators to articulate the rear wheels. For the Audi Q7, Ferrari GTC4Lusso, Cadillac CT6, BMW 7 Series, Mercedes AMG and the Lamborghinis that already use the system, the wheels turn up to 5 degrees.

The 12 degree turn on the F-150 shows how ZF has upped the system for the pickup, and just how much extra maneuverability it will give the car. ZF say that they plan to articulate the wheels up to 15 degrees in the future. The prototype also managed to steer the rear wheels out of phase at speeds of up to 28mph, and in phase when going faster. In cars that already use AKG, the switch out of phase happens at 37 mph, which will probably be nearer the mark when rear drive is available commercially for pickups and light trucks in 2021.

There are more benefits to ZF’s AKG than just being able to get in a parking space. The system can be paired with brake-based electronic stability control. If one of the back wheels has no traction, then the AKG can compensate when the ESC tries to brake with the wheel that has no grip. In tests, this reduced the stopping distance by 20 to 23ft. The same principle can also help with vertical stability, which can keep a trailer under control on windy days.

If the technology seems a little similar to the TRW rear-steer prototypes developed with American Axle, then you probably won’t be surprised to find out that ZF acquired TRW in 2015 – a big part of them adapting their car technology for use in pickups and light trucks.

As mentioned before, the technology won’t be coming to pickups until 2021. Up to date, ZF has made 100,000 AKG systems, but they plan to upscale to 250,000 units a year – which means that by 2021, there will be enough systems out there so that anyone who doesn’t want to get a second smaller car so they can park in town will be able to benefit from this exciting new technology.

From guest blogger Eric White, who writes for 51st State Autos, the UK’s largest importer of American Pickup Trucks in the UK.

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