Deflection and Contact Characteristics of a Power Tiller Tyre

Prasanna Kumar, K. N Dewangan


The power tillers or hand tractors are extensively used by small (1-2 ha holdings) and medium
(2-4 ha holdings) farmers in predominantly rice-growing states in India for roto-tilling,
plowing, puddling, intercultivation, harvesting, transportation etc. The vertical deflection and
contact area of a pneumatic tyre (6.00 x 12 - 4 ply rating) of a popular 6.7 kW power tiller
were determined at 2.38-2.87 kN normal loads and 80-200 kPa inflation pressure on a rigid
flat surface. Both deflection and contact area varied linearly with inflation pressure in the
range of normal loads selected for the study. The empirical equations were developed to
predict the deflection and contact area of the tyre. Further, the power tiller tyre considered for
the study followed the modified universal characteristics of a tyre. However, both empirical
equations and universal characteristics equation of tyres could be used to predict tyre
behaviour under various operational parameters.

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