CAR BRAKES.

Press, Volume LXIII, Issue 18923, 11 February 1927, Page 4

CAR BRAKES.

four-wheel system. WHY SOME EXPERTS CONDEMN IT. <Bv Major F. A. C Forbes-Leith, FR G S., author of By Car to ' India.") If thero is an aspect of motoring which, moro than any other, provokes interesting discussion, it is the question of brakes. One of the prime essentials that must be considered in buying a car is tho efficiency of the braking system, and the ideal has yet to be determined. In the old days of rough, macadam roads the braking system was not nearly so important a matter as it is at tho present time. One's wheels could bo made to grip with greater ease, even if tho brakes of a car did not act with perfect precision. , Tho growth of motoring led to the necessity of an entirely different typo of road to stand tho strain and stress of heavy mechanical traction. Many improvements hnive been mad© since tho demand for this typo of hard roa'l originated, but, as yet, tho most efficient and wear-resisting highway* are by far tho most dangerous to drive upon when tho weather is anything but good. Towards Perfection. There is little doubt that tho fourwheel braking system has been tho most considerable move towards tho perfoct system for work in our own country, or anywhere under similar conditions. There aro, however, still parts of tho United Kingdom whero tho maker of motor roads has not yet penetrated, and which call for a different ty|>o of apulianco altogether. In tho Dominion Colonies and Dependencies, which aro great markets for our produce, thero is another condition to contend with, nnd that is the entire absonco of mado roads. There are great disadvantages as well as great advantages in the fourwheel braking system. Such a system enables one to pull up almost immediately, and if evenly balanced, is less likely to lead ono into a skid than any other type. Perhaps tho disadvantage of these brakes, when motoring on perfect roads, is that they cause you to pull up n little too quickly, and tho man behind you, in spite of the fact that you havo a warning lamp or that you put out a hand, docs not have time to act his eye and foot working in unison. Now, under had conditions of running thero is a distinct disadvantage in the system. In many makes of car tho drums on tho front wheels are oP very nearly as great a circumference as the wheels themselves, and this applies particularly to those cars which are fitted ivitli full-sizo balloon tyres and a small wheel. In Mud and litre. If you aro obliged to pull through heavy mud, or ruts, in the course of your driving, tho front wheels mako a track in which your rear wheels follow. Therefore, you aro bound to havo trouble if you aro obliged to dig so deeply that tho drums of your front wheels aro embedded in tho mire and wet. Such conditions lead to troubles that necessitate dismembering tho mechanism. Thore is nothing moro dangerous or inefficient than four wheol brakes that aro not evenly adjusted with equal pressure both latitudinally and longitudinally, and once tho amateur interferes with tho original adjustment, he is likely to have trouble. Somo drivers prefer tho type of brakes that employ internal and external pressure on tho rear wheel drums alone. They function well in ordinary circumstances, but if tho conditions of driving are such that the application •of both brakes is necessary for long periods, on lengthy down-hill gradients, tho usual result is tho overheating of the drums with the double friction, and troubles follow. Back to Older System. To thoso motorists whoso nocds demand a car that has to function under any of tho conditions I have mentioned, I recommend tho type of car that is fitted with what is considered to be a somewhat old-fashioned system. I refer to the few cars that are still fitted with the main brakes on a drum that is keyed to tho main axle shaft, and the emergency brakes of which apply either internally or externally to the rear axle drums. In the first place, when they are once adjusted, even pressure and retardment of speed evenly on the wheels are ensured. In the second place, cars so fitted aro not likely to give any axle trouble, because the shafts and pinions must be made so strongly that they will withstand the strain of pressuro that is transmitted to the wheels over a distance. And, thirdly, tho front wheels aro left free of encumbrances, and you need not fear for any mechanism when "mud larking." On long down-hill gradients, the foot and hand brakes can bo used alternately, and the danger of overheating is thereby reduced to a minimum. In view of these facts. I am not surprised to find that a certain largo firm of manufacturers have definitely abandoned the four-wheel system in favour of the equipment I have last described.