STEERING TROUBLES

Ellesmere Guardian, Volume XLVI, Issue 3271, 13 November 1928, Page 2

STEERING TROUBLES

Recent changes in the fundamental principles of wheel and axle geometry and steering assembly of practically all automobiles, have left many automobile dealers and service shops groping in the dark to find the cause of steering trouble and tyre wear. These changes did not come gradually—they came with a rush, as a necessary development due to the sudden wide-* spread preference for balloon tyres and the urgent need for additional braking power, given by four-wheel brakes. The sudden demand for balloon tyres a few years ago exposed weaknesses of the then current steering construction in a I glaring light, because balloon tyres brought four times the tread surface in contact with the road at every turn o£ the wheel. And how costly this would prove in case of misalignment is amply illustrated by the fact that scientific demonstrations show that when pitch and toe-in are one inch out of true, a tyre is dragged sideways a mile for every 16 miles of travel. , ' The first step to correct this situation was to "dish" the front wheels, or give them the angle of pitch; so that the wheels were closer together at the bottom than at the top. Second, it was necessary to '' pigeon-toe them, or give them the angle of toe-in; so that the front part of the wheels was closer together than the rear. Ant] then in order to get away from the hard steering, and keep the weight of the car on the centue rib of the tread as the wheels were turned from side to side, it became necessary to tilt the front axle backward, giving the angle known as caster. The correct angles of the pitch, toe-in, and caster had to be determined by experiment; and v was found to vary according to . the length of the wheelbase, the weight and balance of the car, the positions of the springs, and many other factors. With the result that specifications vary for every make of car and truck, and virtually every model.

And whenever the delicate balance of the steering geometry became upset by such a shock as striking a bump or hole, or by sagging of the springs, unequal tension of the brakes; or by any one of many other incidents of ordinary driving, the car developed a tendcnev to weave back and forth on the

road, to wander, to be hard to turn, to scuff tyres, or to shimmy. Any one of these might prove too costly in its damage to tyres, or so dangerous for driving, that correct wheel and axle alignment becomes imperative.