BUNNING MK4 105 - B3105, Instruction & Spares Manual

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LOWLANDER MK4 MANURE SPREADER – INSTRUCTION & SPARES MANUAL
Page
98
8 TYRES AND WHEELS
8.1 Tyre and wheel maintenance.
Maintenance of correct inflation pressure is the basic essential factor in obtaining the
best performance and life from a pneumatic tyre. The air inside the tyre enables it to
carry a load. It is only when the inflation pressure is correctly matched that the tyre
adopts its optimum cross-sectional shape and the tread rests correctly on the road
surface with the correct pressure distribution across its whole width, thus allowing the
sidewalls to provide the required degree of flexibility. Both performance and life of the
tyres will suffer if pressures are unsuitable so both over or under inflation ( or overload
which has the same effect ) are similary undesirable.
Underinflation results in excessive deflection which increases the heat generated by the
tyre, this in turn leads to its eventual disintigration. In addition the distortion of the
casing will result in the lifting of the centre of the tread, thus overloading the outer
edges of the tread, producing rapid wear at those points.
Overinflation distorts the tyre’s casing, but in this case it tends to lift the outer edges of
the tread off the road surface and imposes extra load and more rapid wear on the
centre of the tread. Owing to reduced flexibilty the tyre will be more vulnerable to
impact damage, ride quality will be impaired and the wheels will be more liable to
bounce which can result in skidding due to brakes locking.
Unlike cars on which tyre loads do not vary greatly it is not practicable to provide
standard recommendations. This is because tyre loading and operating conditions vary
widely.
Remember that spreaders travel laden one way and unladen in the opposite direction, it
is therefore desirable to estabish a suitable mean pressure that mimimises both under
inflation when loaded and excessive over inflation when running light.