the move? Its easy

13 March 1998

Inflation on

the move? Its easy

Few operators take the time and trouble to adjust tyre

pressures to suit road and field applications. Perhaps they

would if on-the-move tyre pressure adjustment systems

were more readily available. Geoff Ashcroft reports

AS tractors and machinery get increasingly higher road speeds, tyres are asked to perform ever greater miracles, often without as much as a kick from the operator to evaluate their working pressure.

Yet to get optimum traction, reduced tyre wear and a reduction in compaction, we all know inflation pressures need to be constantly varied.

But how many operators do it?

It is generally recognised that adjusting tyre pressures is a time consuming task, which in most cases can only be done back at the workshop – and when it is done, it is usually to reinflate a tyre after a puncture repair.

So what if tyre pressures could be adjusted from the cab while on the move, simply at the flick of a switch?

Enter the Kunst tyre inflation system used by Ag-Chem on its Terra Gator three-, four- and five-wheeled machines.

Running from the vehicles main air braking system, the Kunst unit allows the operator to pre-programme it with any maximum and minimum tyre pressure settings in the range of 1-4bar (14-56psi).

Once set, the operator can switch between the high pressures required for road work, and the soft inflation pressures needed for field work, all from the driving seat.

"The system is plumbed in to operate on the rear drive wheels, where most of the load weight is carried," says Ag-Chems Richard Palmer. "By adjusting tyre pressures on the move, tyre life is prolonged on the road, and ground pressure is reduced in the fields."

"Because the axles are driven, the plumbing to the wheels has to be down the outside of the machine, but when not required, the system can be unclipped from the hubs and stored safely on the machine."

A neater installation is achieved on the firms Tri-Axer trailed tanker range, yet to be introduced to the UK. Hollow axles allow all the pipework to be concealed within the axles, to feed through the hub and out to the tyre.

Mercedes offers an equally refined installation as an option on its Unimog range. By using air brakes as standard and portal axles, the Unimog has a head start, and air pipes can be plumbed into the axle on the inboard side of the hub.

Called Central Tyre Inflation, the Mercedes system is adjustable over a range of pressures, with built-in safety valves to prevent tyre damage through over- or under-inflation.

Mercedes CTI operates in much the same way as the Kunst system, in that the operator has full control over tyre pressures from the seat. It has the added benefit of being installed on all four wheels of the Unimog and the tyre pressures between front and rear axles can be corrected simultaneously or independently, all on the move.

Still to make the transition to on-the-move status is an air pressure adjustment system offered by Zetor.

Fitting the tractor range with air brakes provides a plentiful supply of air wherever the tractor may be, and by carrying a length of hose and an air gauge, the same effect can be achieved albeit after making a brief stop. &#42

Mercedes CTI system can be specified on the Unimog range.

Kunst tyre pressure adjustment system used by Ag-Chem on its Terra Gator range allows on-the-move adjustments from 1-4bar.

A neater installation of the Kunst system can be found on Ag-Chems Tri-Axer trailer models.

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