Neglect of Tyres

Sun (Auckland), Volume I, Issue 154, 20 September 1927, Page 6

Neglect of Tyres

Motorists are Very Wasteful Information You Should Know • THE loss in £ s d entailed by motorists each year through neglect of their tyres, undoubtedly runs into a large sum. Tyre men are prompt to declare that motorists are wasteful with their tyr.e mileage. This waste is chiefly the result of under-inflation. Car owners have never given serious consideration to the amount of air they put into their tyres.

It is more important to properly inflate balloon tyres to the recommended pressure than it is to follow the schedules set down for high-pressure casings. Having fewer plies of fabric, the balloon tyre gives more to the shocks resulting from road irregularities. Therefore, the sidewalls flex rapidly. They bend like a piece of wire in the hands. To give some idea of how much flexing ithey do, it is estimated that they flex 10,000,000 times in 15,000 m iles of travel. The marvel of it is that they can stand such flexing. It doesn’t take a piece of wire long to heat up and the metal to become fatigued to the breaking point. But tyre fabric will perform prodigies of flexing if it always is supported by sufficient air so the angle of flexing will not be too acute. If pressure is low, the little cotton cords will break and the tyre will fail sooner than necessary. Separation of plies also will be caused as a result of the heat generated by rapid flexing. Premature tread wear will result from a wiping action on the road. With high-pressure tyres, the pressures recommended by manufacturers at one time were placed high enough so that a drop of 201 b did not seriously enda.nger the life of the casing. Manufacturers had anticipated public neglect of proper inflation, and so -when 50 or 601 b of the recommended 701 b remain in the tyre, it was sufficient to protect the fabric from breaks due to flexing. It can be seen that a loss of 31b pressure from 701 b in the high pressure casings represents but slightly more than a 4 per cent, drop, while three pounds loss from a balloon tyre containing 301 b of air is a drop of 10 per cent. That is why proper pressure must be maintained by users of balloon tyres. Through research work in tyre design, tyre manufacturers have made balloon tyres so that, under air pres- > sures recommended, the deflection or flattening of the casing under the weight of the car and a normal load 1 of passengers is about 22 per cent. If this pressure does not remain constant the distortion becomes excessive an 9 , the wear on the tread, through abra-

sive action of the road, is increased many times. The tread then wears out quickly. There is a definite relation between the load to be carried by balloon tyres and the pressures to which they should be inflated. The greater the number of passengers carried in a balloon equipped car, the greater the air pressure necessary to carry the load without harming the tyres. If too low pressure is carried, the tyre will not completely absorb normal road irregularities, but will be crushed to the rim by the weight of the load, resulting in rim cutting and bruises to the fabric, both of which tend to shorten tyre life. If the pressure is too high and the tyre is used under abnormal load and speed the tyre will be ruptured when it runs over stones, ruts or other obstacles in the road. There is only one accurate and positive means of knowing how much air there is in your low pressure tyres. That is by using a tyre gauge. This useful device is so small and compact that it will easily go into the coat pocket or can be carried in the side pocket of the car. It is simple in operation, being calibrated to show pressures in single pounds. The wise thing to do after buying a gauge is to check pressures at least once a week. The most important part of a tyre valve ia the valve inside, which allows air to be admitted to the tyre, but prevents it from escaping once it is in. While the valve inside gives wonderful service, it will wear out, like everything else. It is best to buy a box of five of these valve insides to replace any that may be worn or damaged. Be sure that the valve cap is screwed down tightly on every tyre valve. In case the valve inside is worn out or damaged a tight valve cap will prevent the escape of air. Thousands of motorists operate *their cars without valve caps on the valve stems because they do not realise their importance. Another wise precaution is to have dust caps over all valve stems. This is another matter greatly neglected by the motoring public. Dust caps not only protect the valve stems from injury, but also add greatly to the finished appearance of the car.