New Britain herald., 1922-12-16
WHAT TO DO WHEN
 YOUR CAR SKIDS
Timely Advice to Motorists Using
 Slippery Roads

..EH the car is skidding are equally ~ ..ortant topics.
 The main cause of skidding of rear wheels of motor cars is due to the action of the brakes operating through the rear wheels. skidding, of course. normally occurs only when the roads are slippery.
 An automobile wheel rotates and progresses over the highway in but one direction or plane. This direc- ton tor the rear wheels is determined by the front wheels under control of the driver. While the rear wheels grip the ground and rotate they con- trol the direction of the car. How ever, as soon as the rear wheels are locked by the brakes they begin to slide and as they slide sidewise prac- tically as easily as forward, they lose the power to direct the car.
 It takes comparatively little brake friction to lock and slide rear wheels on slippery roads because there is
 
 the road surface. When once the driving wheels begin to slip the car is kept in motion by the force of in- ertia acting at the cars center of gravity or mass. This forward mo- ton is opposed by the resistance of all four wheels on the ground, a re- sistance that is greater in the rotat- ing front wheels than in the sliding rear wheels. Unless the combined ground resistance of all wheels, tend ing to stop the car, acts on the same point as the force of inertia tending to carry the car forward, there re- suits what is called a force couple" which causes the car to skid or spin around.
 After the wheels once start to slip very small force couple" will pro- duce skidding, and the skid distance is dependent upon the magnitude of the force couple" which in turn de- bends on car speed and weight, Turning the front wheels in the direc- tion of the rear wheels skid, helps to reduce skidding because it reduces the magnitude of the force couple". Also periodically releasing and re- applying the brakes so the rear wheels can get grip offsets forward slip and consequent side skid.
 Two means are employed to pre- vent skidding in motor vehicles. The use of non-skid or rough tread tires and of anti-skid chains. Non-skid !, 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 wheels are blocked:
 Non-skid tires furnish reliability and safety in driving reliability, in permitting the vehicle to operate successfully over almost any kind of road and during all seasons of the year. and safety by permitting the vehicle to hold the road at all speeds, and allowing the brakes to be most | effective.
 Non-skid treads on tires were first | used on rear wheels and are now con- sdered absolutely essential for such uses. Later non-skid tires were | placed on front wheels because the treads prevented front wheel skidding | as well as permitted the rotation or exchange of the front and rear tires |
 A well designed non-skid tread | should give on rear wheels sufficient | forward traction to permit the car to operate without chains under most | road conditions and at the same time | insure against side slip. It must per- init quick and smooth response to | clutch accelerator and brakes. It must not greatly impair ease of steer ing when used on front wheels. It | must not set up vibration in the car noises. It should present an attrac- tive appearance.
 Non-slid chains accomplish the | same purpose as the non-skid tire | tread, that is, give additional traction | and reduce side slip. Non-skid chains should supplement non-skid tires only when road conditions absolutely require them. & @
 Because they make available in road friction the total weight of the car instead of only half the car weight, four wheel brakes are coming | into use. especially in Continental Europe. Not only can cars be stop- ped more quickly but they can be driven safely on wet days and in ice | and snow without chains In stop ping a car equipped with four wheel | brakes all four wheels may slide and | the car as whole slip forward. How ever. there appears to be little or no side skidding. This is especially true If the brakes are connected diagonal y in pairs that is left hand front | wheel and right hand rear wheel. | With this arrangement opposite wheels arc able to roll freely retain ng their directing qualities.