The Winter Slush Look to the Tyres
Page 39
Page 40
If you've noticed an error in this article please click here to report it so we can fix it.
BY ERNEST ALLEN THE coming winter with its attendant road hazards will be in the minds of many transport operators at the present time, and it is as well, before bad road conditions are upon us, that we look to the safety aspects of the vehicle, in particular •the tyres, and to ensure that the drivers are fully conversant with what to do and what to look for in an emergency.
Perusing the Road Research Laboratory's report of accidents involving personal injury in 1961, it is significant to note that on wet and icy roads the total number of accidents fell considerably' in comparison with dry road conditions. This can be explained perhaps by either fewer vehicles on the road or greater care being taken. But in the report the percentage of accidents involving skid ding is as follows: dry roads, 14.5 per cent: wet roads, 35 per cent; and icy roads, 82 per cent.
Improving the condition of tyres can play an important part in improving the position, and the accompanying table should help both drivers and operators in assessing tyre grin under varying conditions.
To the driver, the following points spring to mind in how to interpret the table's figures:— (1) Know your vehicle—especially the tyre and brake condition: (2) avoid at all times locking the wheels—remember that even on dry roads the rubber melted under severe braking tends to lubricate the tyre itself, and reduces grip: (3) a locked wheel leaves little adhesion for steerage: (41 a wet, slushy or icy road demands respect at all times. Treat the brakes, accelerator and steering gently The tyre can't do it all.
For the fleet operator tyres are perhaps the second highest vehicle running cost, and while safety should be the prime consideration, cost has also to be considered if freight charges are to he kept within limits. There is little case in this country for fitting special snow tyres for commercial vehicles, and there
fore it is most important for the normal road tyres to be in first-class condition.
The rate of tyre tread wear is greater in the summer months than the winter months, and also the rate of tread wear is greater with a new tyre than a well worn tyre. It follows that economically it is a better proposition to fit new or good patterned tyres at the start of the winter period, and to run them out during the summer period. While this improves the economy position of the transport operator, it also considerably improves the safety aspect of his fleet. The greater pattern depth enables the slushy, wet conditions of the road to be more easily drained within the tyre pattern, which, of course, is one of the basic functions of a tyre tread pattern.
Proper Reg,rooving
I he. subject of regrooving of tyres is cry much in the public eye at the moment, and indeed some operators are regarding it with a certain amount of trepidation. The fact remains, however, that technically there is nothing against it. providing the regrooving is done in accordance with the tyre manufacturer's recommendations, and that the casing is in no way damaged. It is preferable, therefore, to have a well regrooved tyre running on a vehicle under adverse conditions than a tyre which has very little of the original tread pattern left. Another safety feature which can he
profitably employed by operators is that when the tyres reach half the original pattern depth, the "tie bars" are exposed. and this gives insufficient drainage properties in the tyre for adverse conditions. Therefore, it is advisable to pick out these tie bars with a regrooving tool, and thus provide greater channelling and drainage.
Inflation pressures, .tyre twinning, and the degree of tread weal' should be more rigidly controlled during the winter period than the summer period, and generally speaking there is more labour available to do this job in the winter.
During severe snow and slushy conditions local councils put down as a dressing material a mixture of gravel and salt, and in this mixture there is usually a high percentage of very sharp, flinty stones which do enormous damage to commercial tyres during winter months. Providing the cuts are only into the rubber then very little lasting damage is experienced, but if the tyres are well worn, the cutting extends into the casing and precludes the worn-out cover from being remoulded. This is an additional reason for having well patterned tyres on the fleet during the winter months.