the paradox do away with friction for motor speed and yet for more friction whether you travel on a bicycle wagon or the fastest plane or car this is a motor car we and to this wheel is fastened a brake drum the pluck to which friction will be applied for stopping since friction produces heat the material used for applying friction must resist the if it doesn't it will smoke charred burned and quickly where  lay with every available brick material to choose from through exhaustive test selected the very best for chevrolet brakes brought regardless of the quality of the material the way this material is used is more important for example the amount of braking material in contact with the brake drum largely determines how long the material will last and how effective and safe  are look at this this motor car wheel a spinning and the brake drum turning with a short break you covered with brake material will be used to stop this wheel now want to see how i still longer breaks you less heating less w and no almost half of the drum is covered with friction producing brake material and the wheel is brought to a stop with very little heat or wear it is a simple matter to see that the this of brick and their durable at the depend to a large extent upon the amount of breaking material in contact with the revolving brake drum and the amount of reading material in contact with the not only depends upon the length and number of the shoes but upon the diameter and the width of the brake drum imagine a chevrolet brake without articulated brakes you  break which all outward appearances upright is plenty of brake material to the brake drum but notice that the ends of the brake shoes are fastened to fixed pivot watch as they move about the six point that the end of the moves farther than the part near the pivot as long as the surface of the break forms a perfect circle and as long as the pivot is located in exactly the right place then  the break material will contact the brake drum but you can't use the brakes without making he changes the shape of the brakes you see the issue doesn't fit the dr any more the rigid pivot won't let it so only part of the brake material contacts the brake drum and the part that does wears down first when the brakes you pools off then here's what you g not only the ends of the brake shoes touch the drum and only parts of the braking material are in contact with the drum this is a chevrolet wheel and it's large brake drum twelve inches in diameter these are several a brake shoes notice how long they are how much of the inside surface of the brake drum they cover but even more important notice how they are supported instead of a single p miles hardest driving through the heaviest traffic through any kind of weather regarding how well a brake is designed it's moving parts must be protected from water much mud and in addition the bearing parts against rust by pleading them with cadmium with the inventive resources of experienced engineers in general motors laboratories and the chevrolet engineering department chevrolet has its choice of every available need for connecting brake pedals with brake after all why should there be a problem connecting for mechanical brakes with foot operated cables through a strong sturdy cross shaft and connected for mechanical brakes mechanically with the foot operated what could be simple what could be saved three