Disc Brakes Gaining Wide Acceptance

Press, Volume CI, Issue 29909, 24 August 1962, Page 9

Disc Brakes Gaining Wide Acceptance

[By

NORMAN HARNETT

TN readiness for showtime, beginning with the Paris exhibition and followed on October 17 by the International Motor Exhibition at Earls Court, manufacturers are busy with finishing touches to 1963 models. The more advanced designs will be continued with only detail changes, but some important innovations in the small car field can be expected. One trend that can be forecast is that disc brakes will be pr vided on more and more production cars, including some in the medium-price range. They have proved to be one of the most important advences in safety design of the last decade. It is only 10 years since the prototype for the Dunlop system, fitted to all four wheels of a Jaguar, helped Stirling Moss to win the 226-mile sports car race at

T in the “Yorkshire Post’* Reprinted by arrangement.]

Rheims. Of 34 European models capable of more than 100 mjph., 23 are now fitted with discs. U.S. Lagging The United States has lagged behind in this development. The first series production car to be fitted with discs was the Studebaker Avanti, announced this year at the New York Motor Show. Basically, the disc braking system consists of a disc attached to and rotating with the hub, and a fixed caliper. Housed in the caliper are two opposed hydraulic cylinders, containing the operating pistons and friction pads. Application of the brake moves the pistons forward, bringing the pads into contact with the surface of the rotating disc. Retraction mechanism clears the pads automatically when the brake is off, preventing unnecessary heat from being generated and reducing pad wear. No Fade The outstanding advantage of the disc brake is its resistance to “fade.” It can dissipate heat more effec-

tively than is possible with drum brakes of comparable size and weight, its swept area always being exposed to the cooling air stream. Throughout the life of sthe friction pads, there is automatic adjustment for wear. Constant pedal travel and straight line braking are assured as a result, and there is also a saving in maintenance time and cost.

Another important point is that water and mud do not affect the brake’s performance. Excess water is thrown off by the centrifugal action of the rotating disc, and the braking surface is wiped by the leading edge of the friction pads. This advantage over conventional brakes has been demonstrated on amphibious vehicles to which disc brakes have been fitted, including a new amphibious caravan made in Australia. Worn pads can be withdrawn and replaced by the release of a single bolt. Disc brakes already are available on the front Wheels of many medium powered cars, aS well as on the highperformance models. The next move will be an extension of the four-wheel disc system beyond the luxury range.