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Suspended cabs, seats and front axles are becoming increasingly popular as tractor makers look to find new ways to improve driver comfort and increase productivity. The next stage could be suspended rear tractor wheels. Currently only available on the JCB Fastrac, John Deere is evaluating its own prototype. Steven Vale tracks down the only model in the UK and takes it for a spin.
Fitted to a 295hp 8520, which arrived in the UK just in time for a fleeting glimpse at last autumn's Tillage event, a small number of customers have already had the opportunity to put the QWS (Quad Wheel Suspension) tractor through its paces.
Equipped with ILS, John Deere's front axle suspension system, and RWS, the rear wheel suspension system, and Active Seat, the company intends to use the rest of this year looking for more feedback.
From the outside it looks just like any other 8020 series tractor. However, a quick look at the rear axle reveals a couple of unusual hydraulic cylinders and housings. It looks complicated, but is in fact relatively simple as the basic principle is similar to that used on the ILS suspended front axle. Although the design utilises the transmission, rear differential and inboard planetary final drive assembly, the axle housing is replaced by an inner suspension housing fitted to the differential case. The suspension is provided to each side by a pair of suspension control arms, a tie rod, and two hydraulic cylinders.
The main difference to ILS and RWS is...