The Guy Rigid Frame, Six-Wheeled Chassis

An article from 'The World's Carriers', 15th September 1926. Courtesy of Brendan Kinsella.

The New Guy Six-Wheeler

Quite recently by the courtesy of Guy Motors, Limited, Fallings Park, Wolverhampton, we were privileged to inspect two examples of their rigid-frame, six-wheeled chassis; one fitted with a 56-seater top deck bus body, by Christopher Dodson, Limited, built to the order of the Wolverhampton Corporation, and the other fitted with a 53-seater double-deck body by Messrs. Short Bros. (Rochester and Bedford), Limited, being one of six built to the order of the Morecambe Tramways.

The 56-seater model was fitted with a 45 hp. Knight steel sleeve valve engine, whilst the 53-seater was fitted with a standard Guy 38 hp. four-cylinder engine. The 56-seater has the distinction of being the first enclosed top double-decker on six wheels, whilst both models are said to be the first rigid six-wheeled buses to be mounted on pneumatic tyres.

Plan view showing rear axle.

Both models may, if required, have forward controls as an alternative to the orthodox design. The design and construction of both models were adopted after eighteen months severe tests and experiments to ensure the production of an efficient vehicle which would not only transport passengers over the roughest roads with increased comfort and safety, but which would also cause minimum road wear, and at the same time be economical in both running and maintenance costs.

The forward part of the Morecambe model follows the standard Guy practice, which has proved so satisfactory for their four-wheeled type, i.e., it has the Guy four-cylinder engine with the Guy patent valve design, detachable cylinder heads, and the Guy three-point suspended sub-frame, which carries the engine and gear box, insulating thereby the engine clutch and transmission from all stress due to frame distortion, i.e., when the main frame is badly distorted as a result of an accident, or when one rear wheel is raised a considerable height, the sub-frame remains in true alignment, so that the torsional strain is not transmitted to the crank case and gear box arms, and there is no tendency for the clutch and change speed mechanism to bind.

Another advantage of this construction is that, in the event of an accident and the main frame getting damaged, by unfastening three points of suspension, the sub-frame carrying the engine, clutch, gear box, universal joints complete with propeller shafts can be supported by jacks and the main frame lifted over six units.

53 seater, six-wheel Guy omnibus, one of six for the Morecambe Corporation Tramways.

The main frame, the side members of which are of channel section, tapers to the front and rear, is specially designed to give low loading. The frame is raised over the two rear axles, this raised portion coinciding with the longitudinal seats along the rear of the inside of the body. Although this model has such a low load line there is a ground clearance of nine inches beneath the axle casings, which renders the model eminently suitable for use over rough colonial roads and bush tracks. Further more, the design lends itself admirably to the fitting of a pantechnicon body, with the usual rear well, a point which will be appreciated by furniture removers and others, where the low load line often times makes the difference of one or two men in the loading and unloading of pianos, heavy pieces of furniture and other goods.

In the mounting of the two rear axles the semi-bogey method has been adopted. A strong tubular cross member, connected with brackets, bolted to the side-frame members, central between the two rear axles, takes the weight of the load. At both ends of the cross tube, independent spring swivel brackets are mounted on plain metal bearings, the latter being lubricated by an oil gun adapter in the cap. Two pairs of half-elliptical springs, 3 ft 9 ins. long, are at their centre anchored above and below each spring swivel, the spring extremities are bushed and connected with the axle brackets.

Illustrating the ease with which the bogey can be slid from under the chassis.

Two sets of brakes are provided, both brakes operating on drums, on each of the four rear-wheels. The brake drums are fitted with renewable liners, with flanges which register with similar flanges on the brake drums proper, and provision is made to lead away any surplus oil from the drums; covers are also provided to keep out, dirt and water. The brakes have been carefully designed to give equal braking under all conditions of loading and axle movement.

Illustrating the flexibility of the semi-bogey rear axle over rough ground.

The Guy six-wheeler, showing tyres that have completed 18,000 miles.

The two Guy undertype worm-driven axles are both complete with differential, and are inter-connected with a universally jointed-driven shaft.

The axles are fully floating, so that the weight of the vehicle and load is not carried by the axle shafts. By withdrawing the shafts which are attached to the hubs, and disconnecting the rear universal joints, the whole of the gears and internal parts of the axles can be removed without jacking-up the vehicle or without using a pit. The wheels cannot become detached if an axle shaft breaks.

By unfastening the eight cross tube, bracket bolts and after disconnecting one universal joint, brake rods, and jacking up the frame, the whole rear axle bogey can be wheeled away from the chassis, if this part of the vehicle requires overhauling. This semi-bogey method of mounting the rear axle has many advantages, amongst which are the following:-

(l) Half rear axle weight, consequently tractive resistance is materially reduced.

(2) By having two axles driving, there can be no wheel spin except when the wheels are off the road at the same time, the chance of which' is very remote, furthermore, the elimination of wheel spin reduces the wear and tear of tyres.

(3) Where there are two driving axles, the tendency to skid is very materially reduced. (4) The advantages of four-wheel brakes without complicated front wheel attachment.

(5) Having reduced the load on the back axle by half and, further, owing to the particular type of springing employed, the vertical movement of the vehicle over an obstacle is half, and the vehicle and passengers are only subjected to a quarter the shock.

(6) Owing to the elimination of wheel spin and reduced tractive resistance, much greater efficiency of the vehicle is attained for the same load compared with a four-wheeled vehicle; one obtains reduced petrol consumption. We understand that petrol consumption with the model in question averages from 9 to 9½ miles per gallon.

(7) With the method of springing employed, if pneumatic tyres are fitted and one wheel should deflate, the bus only leans over one-half the amount which the wheel drops by deflation, in fact, it is a negligible amount. During our visit we took advantage of the opportunity to take a short run in the 53-seater model, through the run along the Cannock Road. Both inside and on the upper deck, the riding was remarkably comfortable; furthermore, the shock from the many road irregularities encountered was practically imperceptible. The combined comfort and safety of the Guy rigid six-wheeler should prove highly popular with the general public.

The main dimensions are: four-cylinder model, overall length, 24 ft. 7 ins.; wheelbase, 15 ft.; track front, 6 ft. 3 ins.; rear, 6 ft. 2 ins. Six-cylinder model, overall length, 25 ft. 2 ins.; wheelbase, 15 ft. 9½ ins.; track front, 6 ft. 3 ins.; rear, 6 ft. 2 ins.

With the exception of the engine and clutch of the six-cylinder model, both models are almost identical in other details.

An advert from 1930.

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