PASSENGER TRAVEL NEWS.
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The Latest Doings and Developments in the Bus and Coach World.
EIGHT-WHEELER PROGRESS IN AMERICA.
Brief Details of a Design which Has Proved Satisfactory on a Vehicle which Has Covered about 17,000 Miles,
SEVERAL MONTHS ago we had an opportunity of publishing first parOculars and an illustration ot an eightwheeled motorbus which was being built for service in the United State; and we feel that we are justified in again referring to this vehicle, since it has now travelled nearly 17,000 miles, and is said to have put up a remarkable performance over all classes of roads, it is said that the tyre cost has proved to be only 10 per cent, more than would be the case for adequate tyres on a four-wheeled vehicle carrying the same load and, moreover, that the tyres have given 50 to 60.per cent, longer service,
A company which is devoting considerable attention to the eight-wheeled vehicle is the National Axle Corporation of San Jose, Cal., who are engaged on the exclusive manufacture of buses and other vehicles of this type for California, Oregon and Washington under contract with the Eight-Wheel Motor Vehicle Co., of San Francisco.
Three types of vehicles are being built, a bus which is designed to carry 24 passengers in inter-urban stage service, a street car for 31. passengers and a 4-ton motor lorry. We illustrate an example of the eight-wheeled bus on this page, and this particular vehicle is the one which has covered about 17,000 miles.
So far as the principles of construction are concerned, in these eight-wheelers, the chassis are built with four front steering wheels and four rear driving wheels, designed so as to give extreme flexibility in both front and rear sets. The load is thus, distributed over eight
wheels, and each wheel carries, it is claimed, half as much load as would be the case if there were only the usual four wheels. As a matter of fact, the difference is even greater, for the simplesreason that the eight-wheeled chassis is built with the centre of gravity farther forward than in four-wheel chassis. In the eight-wheeled chassis the four rear wheels carry only about 55 per cent, of the total load, whereas in the ordinary type of vehicle, as much as 85 per cent. of the total load is carried by the back wheels.
The two front axles are connected by springs on each side so arranged that the axles oscillate about a central trun nion bar. Any damage to any one of the wheels does not materially affect the steering.
It has hitherto been the practice in the . design of some four-wheeled vehicles to cant the front wheels in order to offset drag due to the plane of revolution of the wheel being outside the pivotal point of the steering knuckle. This feature has been eliminated in the eight-wheeler by making the tyres revolve about the point directly under the steering pivot. The chassis is fitted with a separate brake upon each of the eight wheels, so that the safety factor is considerably increased.
Another innovation in the eightwheeled vehicle is a transmission providing eight speeds forward and two reverse. The manufacturers consider that the use of four or five-speed transmissions is not sufficient to meet the requirements of passenger-carrying service where frequent stops are made, and it is necessary to secure quick acceleration.