Let them be light
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PRODUCING a vehicle plated for )nly 36 tons before the findings rf the Armitage Inquiry into naximum gross weights are .nown is not the result of any )rivileged foreknowledge on :RF's part.
But the 36R 4x2 tractive unit is I new addition to ERF's model ange, and, although expected o replace the established 38R2 or most UK operations, the ieavier model should also stay ,vailable.
ERF believes that with the I6R2 it has produced a vehicle larticularly suited to present leeds. There's potential for an xtra 1/2 a ton of payload, which gust mean greater productivity. Engine power ratings have leen increased over recent ears to match higher plated weights. For UK operations mited to 32 tons, the extra ,ower has reduced the driver's aily workload.
Here, the 36R2 has kept the owerful Rolls-Royce 265L turocharged diesel engine giving n installed output of 194.5kW 261 bhp). Superficial modificaons and some redesign work educing the sump capacity .om 29.5 litres to 25 litres (6.5 allons to 5.5 gallons) has
amounted to a 13.6kg (30 lb) weight saving.
Rolls-Royce have reasons for reducing the engine's oil capacity other than weight saving. The power unit, frugal in its use of fuel, has developed a thirst for oil, mainly, it seems, because of overfilling. Reduced capacity is said to improve the dipstick reading and is reflected by better consumption keeping more in line with other engines currently in use.
The popular Fuller RIO 9509A nine-speed range-change constant-mesh gearbox is unaltered in the specification, but the Dana Spicer 365mm (14in) diameter twin dry plate clutch is now enclosed by pressed steel cover in place of the former substantial cast iron one, Prop-shaft dimensions will remain unchanged for the time being until the Hardy Spicer Compact and the light range of Dana Spicer become available in production quantities.
At the rear end, the Kirkstall D65 axle, giving the same final drive ratio as the 38 tonnes vehicle, has its origins with ERF's eight-legger, where it forms half of the 18-ton rearbogie. In this application, unrestricted by load limitation imposed by axle spread, it is rated for a full ten tons and geared to give a top speed of about 100km/h (62mph).
Taper leaf springs on the rear axle make a reduction of about 40kg (90 lb) over multileaf semielliptic springs, which, however, are still used on the front axle.
Tighter quality controls by the steel makers has enabled ERF to use a deeper 300mm (11,18in) 90mm (3.5in) wide but thinner 6mm (0.24in) chassis frame while claiming to maintain existing stress levels. Welding of intermediate cross members instead of bolting or riveting also helps to shed a little more.
Use of a round aluminium 273-litre (60-gallon) fuel tank in place of a square steel one reduces the vehicle's unladen weight of 22.6kg (50 lb) and an aluminium bumper trims off the pounds still further. A large chunk of metal disappeared with the introduction of a single conical airfilter, no longer needing the support of the heavy steel gantry. Using a single filter in place of two might suggest that the element would need replacing twice as often. Not so, say ERF. The element has a much greater dust-holding capability and although it will look dirtier sooner, the more efficient conical design will go on for longer before reaching the critical point when the air intake becomes restricted.
Replacement should be determined by the restriction indicator and not by the colour of the filter element.
In striving to find areas in which a few pounds could be trimmed off, ERF engineers were equally determined that the quality and durability of individual components should not be downgraded.
The pressed steel radiator and integral header tank is not only better from the aesthetic viewpoint but provides perfectly adequate cooling and gives a life expectancy equal to that of the traditional design.
In other areas too there has been rationalisation. Introduction of a circuit protection valve into the air system completely eliminated the need for the two tanks mounted on the gantry at the rear of the cab and resulted in a reduction in capacity of a third.
With the ZF steering gear the search for weight reduction has led to small but worthwhile improvements. The removal of the bevel box makes the unit more compact and allows the lower joint to be sited below floor level leaving the area around the bat,tom of the steering column inside the cab much tidier.
The cab — a compoundpanelled corrosion-resistant construction based on a steel safety cage — is, by the nature of its design, lightweight and strong. Recent modificatioi allow tilting without the need remove any of the cab pane The front looks neater too wi the headlamps faired into ti body lines and a full-width to hinged panel gives unhinden access to the front end of ti engine.
Ready for the road, the El 36R2 has an unladen weight 5.48 tonnes and compares w with the few other 4x2 tracti units built to the plated weig about the 36 tonnes mark.
The Seddon Atkinson T weighs in at 6.23 tonnes, ti Dodge 3620P at 6.1 tonnes, al DAF's FT2300DHU at 5.l tonnes. Only the Volvo F7, witt much smaller and low powered engine, can better it 5,47 tonnes.
Further weight-saving — the region of 120kg {265 lb) can be made by including al minium wheels, but the adva tages must be weighed agair the cost, said to be around £9 for a set of six.
If there is room on the sen trailer the extra half ton capac equates to 31 trusses of stra 870 pints of beer, or, for the lor driver with a sweet tooth, 9,6 two-ounce bars of chocolate.
Many of the weightsaving fe tures are applicable to ERF's s and eight-wheeler models.
Below: Cab styling has been i proved by recessing the tin, headlamps into the body line. 7 wash/wipe system is an optic', extra.