LOWER SPEED

Auckland Star, Volume LXXIII, Issue 123, 27 May 1942, Page 5

LOWER SPEED

TO SAVE TYRE WEAR

GENERAL LIMIT SUGGESTED

(0.C.) NEW PLYMOUTH, this day

Because traffic density has been reduced as a result of the rationing of petrol, the tendency of many drivers is to increase speed outside town areas where the limit of 30 miles an hour applies. Speed is one of the main causes of tyre wear, and where motorists, by speeding, disregard the appeal to conserve tyres, the imposition of a general speed limit may become a necessary discipline.

The inevitable result of speeding js increased wear on tyres, not only through ordinary friction, but also because speed leads to hard and sharp breaking. On any concrete road can be seen the black marks caused by tyre rubber scraped off when a vehicle has been suddenly slowed. Quick acceleration and deceleration shorten the life of tyres, and this, in combination with speed, has a very deleterious effect.

Another cause of rapid tyre deterioration is neglect to maintain! proper air pressure. Taranakl garages and automotive engineers generally recommend tyre pressures of at least 301b for light cars. Although this is oTten in excess of the maker's recommenation and makes the ride less comfortable than on soft tyres, it lengthens their life considerably. An example has been quoted of a light car which has run 28,000 miles on one set of tyres which are still in good condition —the spare is almost unworn—as a direct result of the constant maintenance of a pressure of 301b.

Cornering at speed is another serious cause of tyre destruction, as also is the parking of cars against a kerb on a slope with the edge of the kerb biting into a tyre. This fault is not so common as it was, but it is still observed. What happens is that the pressure of the edge of the kerb bursts the cords of the lining and thus causes the casing to collapse at the point of damage.

Another fault is that of over-load-ing small cars, particularly when tyres are not sufficiently inflated. Speeding, however, is the most common cause of tyre destruction, to say nothing of its high demand upon petrol.