Road and workshop by Handyman
Page 34
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Manpower, maintenance and the MoT( 1 7)
• With today's larger range of tyres there is nOw more than ever a need to extract considerably more in the way of tyre-life mileages. Because it is fairly certain that since April 1 1968 tyre condition and inflation pressures receive more of the attention they have long deserved. I shall now turn my sights upon the rate at which rubber is removed in service.
Quite a number of people operating the heavier range of haulage vehicles are looking with considerable gloom at the mileages being obtained from tyres on the modern artic, particular emphasis being placed on the driving axle tyres, where power and braking together are removing rubber at quite a fantastic rate with a naturally poor mileage. It appears that the once attainable 1d per mile tyre cost is now as dead as the dodo, and the target now looks very much nearer 1.5d as the best figure. with rather disturbing excursions to around 2d, which have already been a good enough reason for some road and workshop investigations.
This brings me back to the subject of the driver and his further education, as it is now accepted that he has at his fingertips the means of extracting the best, or the worst, tyre-life figures by his style of driving. This does not in any way make him a poor or unsafe driver. In fact there are drivers with accident-free records over many years, but who consistently return quite low tyre mileages due mainly to cornering with a heavy vehicle under full load, The point of criticism is the habit or arriving into the corner still under heayy braking power, and causing two thitigs to take effect: (A) a tendency for the vehicle to resist a change of direction while under full braking; (B) the transfer of weight across the chassis onto the wheels on one side. Thus a fourteenwheel artic may take its full gross tonnage on seven tyres only for many, many yards, and rubber is literally ground away.
At any busy corner or traffic island on a dry day watch out for those dark stains on the road they're rubber! The tyre-conscious driver, on the other hand, travels hardly less slowly over his journey but does all his heavy braking on the straight with all tyres equally load-bearing, once in the corner moderate throttle takes him around on almost a level keel with no serious weight transfer.
The difference between the tyreconscious driver and the one who just belts round corners regardless, can be as much as 45 per cent in tyre mileages.