Survey finds over inflation
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• A major inspection td 1,76z4 truck tyres has concluded that 704 of vehicles run with overinflated tyres. Furthermore, examination of debris from 157 tyres collected from the M4 showed that three-quarters of the failed tyres had run while deflated.
During the survey tyres on 2117 1 R;Vs were examined at Micibury service station on the M4 and actual and plated axle weights were noted. This showed that the average tyre was inflated to within 3% of the pressure recommended for the plated axle weight. However, on weighing the axles they were, on average, found to be running at 71% of their plated load. The tyres were therefore over-inflated by an average of 36% .
According to the Tyre Industry Council this degree of overinflation results in a 15(4 reduction in tyre life. This will cost the operator of a 17-tonner 1120 per truck, per year. says Central Tyres' Mike Swain.
This contrasted with threequarters of the 157 tyres that were collected as debris which
showed signs of running flat. Casuses for deflation could be concluded for over half the sample. Punctures caused 38 failures. Tyre damage accounted for 'bi% of failures and faulty repairs. 1 1 (.4 .
Of the debris collected 54% was front retreads and 46% from new tyres while all hut 12 of the 157 tyres were tubeless. However. the report points out ihat new
tyres are normally used on front axles and the driver would be immediately aware of a puncture and stop before the tyre breaks up.
In addition a disproportional number of wide single trailer tyres were collected. The conclusion is that much of the weight front a punctured twin wheel is taken by the good tyre so preventing the deflated casing breaking up.