New Seddon Seddon 6x4 chassis
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• Six-wheelers for gross weights of 20 and 22 tons have been introduced by Seddon Motors Ltd. There arc two basic models, each with a double-drive rear bogie and four-spring suspension of the same design. A 20-ton-gross chassis is based on the Seddon 13:four four-wheeler with the Perkins 6.354, 120 bhp gross engine, while the second is plated for 22 ton gross and is based on the 16:four with the Perkins 180 bhp gross V8.
There are four wheelbases for the 20-ton model-10ft 9in., 15ft 3in., 16ft and 17ft 4in.--the two shorter chassis being designed for tipper use. But the 22-ton-gross model comes in two wheelbase dimensions only 16ft and 17ft 4in. Prices for the lighter model vary between £3,325 to £3,385 and estimated chassis /cab weight is 5 ton 8 cwt. The two V8 chassis are priced at £.3.975 and £3,985 respectively and chassis /cab weight will be about 5 ton 18 cwt.
The rear bogie is based on Seddon 9-ton axles with Eaton driving heads incorporating a lockable third differential. The 22ton-gross chassis has single-speed heads with a ratio of 6.5 to 1 but a two-speed bogie is standard on the 20-ton-gross 6 x 4 and the ratios are 8.53. and 6.14 to 1; the two-speed bogie is an option on the heavy chassis.
The four-spring bogie suspension is a conventional layout and there is a rubber buffer above the balance-beam end of each spring. Front telescopic dampers and power steering are standard. Both chassis have five-speed, direct-top, constant mesh gearboxes. There are different intermediate ratios in each case and a six-speed overdrive unit is an option on the 22-ton-gross model.
Braking on both models is by an air-pressure system with wedge brakes all round —7in. wide at the front and 6in. wide at the rear with drum diameters of 15.5in. The mainand secondary-brake requirements are met by the use of a split system. The front-brake actuators are of the piston /diaphragm type and each section is on an independent circuit with one of the rear axles and piped to separate air reservoirs through a dual foot-valve. There is a mechanical parking brake, linked to the rearmost axle only, on both models and with a single-pull lever on the 20-ton-gross chassis but a multi-pull mechanism on the heavier models.
Main chassis side-members are 10.5in. deep pressed-steel channel but there are 12in. deep channel members on the outside of these which run from the extreme rear end to the rear brackets of the front springs.