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Lower tyre pressure will allow greater traction and a bigger contact
area to the soil, but can also lead to greater rolling resistance.
Tyre width
The use of wider or double wheels will enlarge the tyre contact area
on the soil and therefore better traction (
Figure 3
on page 56). Wider
tyres will also reduce soil compacting.
Wheel slip
A certain percentage of wheel slip is required for good traction.
During wheel slip, the ground particles are compressed to create
traction.
However, there is an optimum wheel slip percentage for different
soil types. A too high wheel slip can reduce traction and also in-
crease fuel consumption.
Graph 2
shows that maximum traction
power takes place at optimal wheel slip.
Implement hitching system:
Three-point linkage
The resulting pulling force is perpendicular to the ripper tine shears.
The pulling force is at an angle downwards at the back of the trac-
tor and the moment is around the rear axle of the tractor wheels.
This causes more traction on the rear wheels, but tends to lift the
tractor’s nose and front wheels (
Figure 4
on page 56).
Graph 1: Effect of wheel load on traction.
Graph 2: Effect of wheel slip on traction.
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