TWO EFFECTIVE TYPES

NZ Truth, Issue 1189, 13 September 1928, Page 23

TWO EFFECTIVE TYPES

When Selecting Shock -absorbers

TJNTIL springing systems have been perfected, compromises will be necessary to stamp out the violent bouncing cars are subjected to on rough roads.

■THESE compromises take the form of 1 shock absorbers, ■ snubbers /or "levellers," and though they are all designed with the one end m view, they do not act m the same way to achieve that end. They can be of the moat intricate and costly design, and m another form can be extremely simple. "You pays your money and y6u takes your choice," as the coster said to the old lady. : The only consideration is what exactly the shock absorber is intended to do. > With a new car already fitted with a damping 1 device, one has no worry, as the makers are not likely to make a. mistake. In "choosing a set of snubbers for a car .not fitted with them, several considerations enter into the question. Shock absorbers are divided into two main classes, those which act only one way, and those which act both ways. The latter can be divided into two classes — friction and hydraulic types. • /Single acting absorbers only come into play on the rebound of the chassis. They do not tend to prevent the wheel being pushed upwards. They are Intended only to damp out bouncing and so bring the body of the car to rest as quickly as possible.

The double-acting type tends to prevent any motion of the spring, either up or down. This type undoubtedly is most effective m its hydraulic form. In choosing one of these three types the class of the road which is to be mainly traversed and the speed at which the machine is intended to , be driven are the principal considerations. On good and fairly good roads, and at moderate speed, the' single-acting absorber acts satisfactorily. If bad roads are to be covered the double-acting type is to be preferred. If the driver demands speed,, whether the road be good or bad, the hydraulic snubber is unsurpassed. It will almost entirely prevent spring breakages, and will enable' a much higher average speed to be maintained over rough . going. After fitting any damping device, experiments should be carried out to secure the most effective results. Remember that the farther the dampers are fitted from the centre of the axle the more powerful will be their effect. On heavy cars they must therefore be fitted as closely as possible to the wheels.