THE TRACTIVE PERFORMANCE OF RUBBER TRACKS AND A TRACTOR DRIVING WHEELTYRE AS INFLUENCED BY DESIGN PARAMETERS

The tractive performance of an experimental rubber track unit was comp ared with that of a 16.9 R34 tractor driving wheel tyre, in 14 differe nt field conditions, using a single wheel tester. In 1989, the track u nit was fitted with a thinner, flexible, friction-driven rubber track having less aggressive lugs than that of the tyre. Tests were carried out with vertical loads of 16.68 kN and 19.62 kN for both the track an d the tyre in eight different field conditions. The rolling resistance of the track was found to be higher than that of the tyre because of the internal power losses within the track and losses between the driv ing sprocket and the track. The coefficient of traction produced by th e track was higher than that of the tyre, but the tractive efficiency was lower, due to its higher rolling resistance. The coefficient of tr action at which maximum tractive efficiency was achieved with the trac k was always much higher and the corresponding slip was always much lo wer than those achieved with the tyre. The significance of this is tha t a rubber-tracked vehicle could be much lighter than a wheeled tracto r of the same power and still achieve the same tractive performance. I n 1990, the same tests were repeated with two thicker, positively driv en rubber tracks having different tread patterns, and with the same ty re in six different field conditions. The results of the comparison co nfirmed those of the previous investigation. The tread patterns had no statistically significant effects on their tractive performance.