The Big J Series was available in a range of different forms, with a choice of engines, gearboxes and axles to suit the individual requirements of heavy haulage operators.
They were suitable for both long distance, high mileage work, or for short-run deliveries and could handle the toughest off-road conditions.
All models in the ‘Big J’ range incorporated an all-bolted frame assembly, to a standard width of 34 inches and parallel throughout its entire length.
Rigid assembly was ensured by the use of pressed channel section silicon manganese steel members, which were strongly braced throughout by pressed steel, built-up cross-members.
Towing facilities consisted of reinforced holes in both frame members at the rear and tapped holes in the bumper brackets at the front to take screwed towing eyes.
Dual-circuit brakes of the full air-operated, drum type were fitted to ensure safe and powerful braking under all conditions. Fail-safe spring-actuated secondary and parking brakes were also provided to ensure that in the event of a loss of air pressure, brakes were automatically applied.
Five or six-speed constant mesh gearboxes were fitted as standard. Both were identical except that an additional gear-train, and an extra selector fork were fitted to the six-speed box. The five-speed box had a direct drive top gear, while the six-speed box had an overdrive top gear giving higher road speed under light load conditions. Alternatively a ten-speed up-split constant mesh gearbox could be fitted.
Provision was made on the right-hand side for the fitting of a full torque power take-off unit. Alternative power take-off units were available for left-hand mountings.
The standard cab for all Big J models was an all-steel welded assembly with entrance steps ahead of the front wheels. The assembly consisted of a sub-frame and panels, which together provided maximum rigidity and durability. Bolt-on wings and front corner panels were provided for ease of repair, or replacement.
Emphasis was placed on the roomy interior, and driver-comfort using high quality trim, and comfortable seating to enhance the spacious cab design. The wide doors were carried on robust external hinges, and two large grab-handles were fitted to ease entry and exit. The entrance steps were fully enclosed by the door panels, and a large glazing area was provided for exceptional all-round visibility.
The instruments were neatly positioned in the fascia panel, with all control switches in easy reach of the driver. A fully upholstered, shock-absorbing seat was offered as an optional extra, which allowed adjustment over a wide range of positions to suit any driver or passenger.