Where the personal touch counts
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'various shapes. Some, like the Volvo F88, offer suspension seats that can be set to suit the individual's height and weight.
Although the high driving positions for the Ford and the Leyland Marathon provide, in my opinion, benefits in terms of. visibility, any amount of roll experienced is exaggerated.
Hard to beat
The standard of all-round vision provided by Volvo's F86 cab, originally introduced in the sixties but modified to conform to the Swedish crash regulations, is still hard to beat.
Steering wheels vary in size from about 431mm (17in) diameter to the largest I have seen, 610mm (24in),.fitted to the DAF 2800. This one tends to dominate the driving position but provides a very nice feel when connected to its Zr power. steering. The mate's seat here is adjustable in every direction and even fully reclines.
Foot pedals vary in height from the floor, but if they are too high this only means wasted effort. An air-assisted 'clutch as fitted to the Scania LB81 can be a great assistance provided it has a sufficient reservoir to cope with successive changes.
Fatigue
Brake pedals should provide a good progression with a greater sensitivity at the lower pressures. The throttle pedal, too, can be a source of fatigue if the return spring is too heavy. Ford suggests that 4.5 kg (10Ib) is about the right load.
The gear change, whether to a splitter or range change box will serve best if the gate layout is conventional with the highest gears nearest the driver: on long hauls, the gears used most are those with the highest ratios.
The range change, with a basic four-speed gate, is easy to use, while the splitter box has the advantage that-every other half gear can be pre-selected.
Gone are the days of the multi-pull park brake. As weights have increased and heights have become bigger, the .handbrake levers seem to have got smaller and, in most cases, now control air-operated spring brakes.
The same lever moved in a different direction is often used to operate the secondary brake system and on the Foden 8LXI3 has a protective latch 'arrangement to prevent the park position being engaged inadvertently, while the vehict is in motion.
Popular
Positioning can improve thE safety aspect as it needs to be placed close to hand in case of emergency. Scania put its or just below the dash, protected by a sleeve on the near side of the steering column, but a popular position is on top of th dash as in the Berliet 280.
Noise from the engine can be reduced in various ways wii the last line of defence a thick rubber mat covering the complete floor pan which has the advantage of being easily kept clean. Volvo is one of the few which offer a little more luxury with full carpeted floor and engine cowl.
Exhaust brakes can work well if used correctly in conjunction with the gearbox but like many other British drivers I tend to rely to a great extent, on the service brake.
Electric transmission retarders are becoming more common now and might be a better investment with the various sizes and installations now available.
Effortless
The big modern high torqui rise engine provides effortless high speed running combined with a great deal of flexibility a low speed.
Many of the points made in respect of the largest vehicles are also applicable to smaller vehicles and visa versa but witl greater or less emphasis.
In the 16-17 ton range, for example, with smaller less powerful engines coupled to five and six-speed gearboxes
stead of 8 or 10, the spread .twee n the gears becomes more ;ute to cope satisfactorily with II.climbing.
The external ram is used Jite commonly to provide ;sistance to the steering as on e Seddon Atkinson 200 and the Chrysler Dodge Commando. But others like Bedford's TM retain an integral unit.
With the smaller vehicle and the likelihood of shorter hauls, access gains in importance. The TM is well provided for with two steps up to the driver's seat; the DAF has only one with a high second step and the Dodge is just a little better.
Instrumentation tends to be less extensive, ranging from quite a basic layout on the Bedford TM to the fully
instrumented dash on the .Dodge and many include a rev counter which is a must to get the best out of the engine and gear box.
Although warning lamps for coolant oil and battery levels are often included with the instruments, the ability to be able to make a physical check is reasuring at the start of the day, and, in most cases, can be done without having to tilt the cab.
Practical Mirrors are often selected for, aesthetic rather than practical reasons. Rear vision is no less important for the driver of a small vehicle than for a large one and I prefer large mirrors with a slight convex face providing an enlarged picture of the road behind.
Plastic seats are not uncommon in this-weight range. But cloth covered seats as used in the DAF 2000 are well worth the extra cost: think of the saving in drivers' sweat!
At the light end of the range with panel vans, ease of entry Must come near the top of the list of priorities. Here, the bonneted vehicle with a wheel arch, which is less inclined to intrude into the door well area, can provide some advantage. But it will depend on the positioning of the seats and controls inside in relation to the door opening.
Sliding doors tend to be more draughty and are inclined to rattle when they become old. But they provide distinct advantages for the driver who has to make repeated drops in busy shopping areas.
The hydraulic braking system often has vacuum assistance. But the handbrake lever, usually more conveniently positioned one side or the other of the seat, operates mechanically on the rear wheels. The whole driving position is inclined to be more car like with no reason for pedals to be badly placed.
Most models . .
In most models, the cab is integral with the load area without a full height bulk head behind the seats to protect the driver from the load moving forward. The problem here is that not all loads extend to roof height and it can be more convenient for the driver to unload a package from the cargo area just by leaning over the back of the seat. A nylon net of webbing adjustable to designated heights with fixing to the floor, roof and side pine' would seem to be to be a versatile answer. • Bill Broca