Show AVOID SKIDDING BY TWO TO METHODS rough tread tires or chains will prevent trouble to considerable sid erable extent why nn an automobile skids Is of interest to a motorist but what nhat to do to prevent skidding i and what to do a when nhen the car Is skidding are equally important topics the main cause canse ot of s1 sa of rear wheels of motor cars is due to the action of 0 the brakes operating through the rear wheels wheela skidding of course normally occurs only when the roads are slippery an automobile wheel rotates rind and progresses over the highway in but one direction or plane this direction for the rear wheels Is determined by the front wheels under control of thed the riNer while the rear wheel ls grip the ground and rotate they control the direction of the car Ilowe however vcr as soon as the icar wheels are locked by the brakes they be begin in to slide and as they slide aldeN lse practically ns as easily as forward they lose the power to direct the car little friction locks wheels it takes comparatively little brake friction to lock and slide rear wheels on pery roads because there Is little friction between the tire and the road surface when once the driving wheels begin to slip the car Is kept in motion by the force of inertia acting at the cars center of gravity or mass tills this ani forward aard motion la Is opposed by the resistance of till all four wheels on the ground a resistance that is greater in the rotating front wheels than in tile the sliding rear wheels unless the combined ground resistance of all wheels Mi eels tending to stop the car nets acts on the same point as the force of inertia tending to carry the car forward there results what Is called force orce couple which causes the car to skid or spin around after the wheels once start to slip it very small force couple will produce skidding and the skid distance is dependent upon tile the magnitude of the force couple which in turn depends on car speed and weight turning the front wheels in the direction of the rear wheel skid helps to reduce skidding because it reduces the magnitude of tile lie force couple also periodically od leally re releasing lensing and reapplying applying re the brake so the rear wheels can get a grip offsets forward slip and consequent side skid ways to prevent skidding two means are employed to prevent skidding in motor vehicles the use of nonskid or rough trend tread tires and of antl anti chains nonskid tires are designed to give forward traction and to prevent side slip As long as there Is traction the rear wheels will turn and as long as the rear wheels turn there will be no serious side slip unless the front v heels abeels are blocked nonskid chains accomplish the same saine purpose as the nonskid tiro tire trend tread that la 19 give additional traction and reduce side slip nonskid chains should supplement nonskid tires only when road conditions absolutely require them |