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Pat Kennett takes a look at the past Iwo decades of ERF as part of Commerical Motor's Milestones series.
MTwenty years ago ERF was producing a typically English wagon which carried the hallmark of 1930s truck engineering; the era when the marque was born. Now its vehicles are as up-to-date as any.
But at what point did the transformation begin? Up until the early seventies all those "vintage" features from the thirties were still there, including a coachbuilt cab with a wooden frame. The transition point came with the introduction of the A-series in 1972.
Although the A-Series cab remained much the same as its predecessor, with plastic panels on a mainly timber frame, its chassis was completely new and pioneered numerous areas of technology that were later to be adopted by others. ERF was the first truck manufacturer in Europe to use spring brakes, for example.
Construction and Use regulations at that time forbade "the use of stored energy" for the park brake. The rule was intended to ban air or vacuum cylinders in the park system, on the obvious grounds that the pressure/depression could leak, letting the truck run away — but it also banned energy stored in a spring. Constant badgering at the Ministry of Transport (as it was then) got the wording changed.
In the meantime other manufacturers Like Atkinson had opted for lock actuators and lived to regret the decision. Slightly worn lock actuators often refused to release no matter how hard the driver tried to build up air pressure. Hardrevving engines trying to raise air pressure for the lock actuators won trucks a lot of enemies.
INCIDENTAL It is arguable that the A-Series was the first truck chassis, at least in Britain, where good ride and handling characteristics were actually designed in. Prior to that the chassis were designed primarily to carry the load, and any handling habits that resulted were purely incidental.
Suspension on the A-Series employed very long parabolic springs with, for their time, unusually large telescopic dampers. Long springs were common on Continental chassis, but they suffered from an excessive laden-unladen height difference on tractor chassis which led to coupling difficulties. Remember thfrise 1970s Mercedes, Fiats and Maggies? ERrs A-Series conquered the height problem for the first time; it achieved a soft controlled ride with only about 100mm laden/unladen height shift by pioneering compound-rate parabolic springs.
The front springs were equally long, and were aided by the biggest dampers anyone had ever seen. Another important chassis feature was the crossmember design, coupled with the spring brackets. The crossmembers, in plan view, were of narrow "X" form in the rear half of the frame, and so were extremely stiff. They bolted straight through to the spring brackets using torqued up fitted bolts — a technique used last year on the Renault AE Magnum and claimed as a hi-tech innovation.
The A-Series was one of the first in the UK to use ZF power steering, which helped the overall package of chassis stability and directional precision. A large, stiff crossmember which protruded through the front cab panel — a good recognition feature — further improved frame stability, and thus handling precision.
Trevor Longcroft's CM test report in March 1972 included some interesting comments: "Relocation of longer springs to the outside of the chassis members and inclusion of dampers on both axles provided excellent isolation from the highfrequency irregularities prevalent on some sections of motorway." He went on: ". . . the steering was most impressive, relationship between wheel diameter, turns lock-to-lock and applied rim pressure being the best I have encountered".
ERF's newly emerging skills in transmission matching were illustrated when Longcroft wrote ". . . assessing the road conditions ahead, it was possible to remain in a relatively high gear, allowing the engine revs to drop back towards peak torque . . . flat between 1,550 and 1,300rpm". This was with the new Cummins NHK 220; the 12.2-litre predecessor of the 14-litre Ni' engine.
Hard on the heels of the A-Series, which won ERF a record 2,000-plus sales in 1973, came the B-Series range.
The chassis engineering was fundamentally similar to the A-Series, but the cab was completely new. Not only was it a new design and shape, but it embodied a new construction technique. A steel skeletal frame carried bolted-on moulded SMC panels, with a high standard of furnishing and fittings inside. It was also the first British-made truck cab to meet the ECE.29 European cabstrength regulations. In fact, during strength testing on a rig at MIRA, it went past the 12-tonne roof-load mark, and the engineers decided to see how far it would actually go — the rig failed first.
'Ishe B-Series was launched at the 1974 Motor Show at Earls Court in a dazzling orange and white paint job. Two tractors were shown, one with a Cummins NH 220 engine, the other with a Gardner 8LXB rated at 179kW (240hp). At 32 tonnes GCW both units gave high power to weight ratios by 1974 standards.
TURNOVER
FRI,' Bs grabbed the attention of UK hauliers and the vehicles became the main factor in ERFs record 21.7m profit in 1977, from a 238.4m turnover (also a record figure). By today's standards those figures sound modest, but remember that in 1976-7 a premium tractor cost about 211,000.
CM was enthusiastic too. Graham Montgomerie enjoyed his drive when he took a B-Series for a ride in September 1974. The files record; ". . . the tractive unit on its own, as well as in laden 32-ton form . . . was pleasantly surprising with its lack of bounce". He went on to talk about the ride: "A characteristic which showed up well was its behaviour on roads with long undulations rather than small bumps." Elsewhere in his report Montgomerie recorded that "the performance of the ERF on the hill sections was good" and the brakes were "very reassuring".
A few years later CM's David Wilcox reviewed some operators' impressions. Ken Beresford spoke about his Bs on Continental work: "They are reliable, so problems with breakdowns or spares rarely occur." Other points highlighted by Beresford include the excellent Fuller gearbox, corrosion-proof cab and exceptional braking.
MODIFICATIONS
The fundamental concept of the B-Series has carried through to the 1990s very successfully. The C-Series contained some engineering changes, including the first turbo-Gardner engines. Cab modifications included a bolder, smarter grille, and new trim and interior insulation.
Later C models incorporated the "CF' concept, which was an effort to rationalise production into a number of standard-spec models with Cummins engines, Eaton boxes and Rockwell axles. It was still possible to have your own spec ERF, but operators waited longer and paid more. The CP chassis were sharply priced, and quickly available, so establishing ERF as a tough competitor to the imported makes. There was no D-Series, but in 1986 the E-Series was launched and became the most successful ERF ever, accounting for more than 4,000 sales in the 1988-89 trading year. The E featured a number of innovations. Among them were the Eaton 4106/6109 transmission; the Twin Splitter and SAMT transmission; the C-type "265" Cummins engine; the 10-litre "325" engine; the 14-litre "465" engine; and the Rockwell "Cameri" axle. All appeared on the ERF "E" before any other truck.
Another first was the Cummins 6BTA 134kW (180hp) engine in the 16-17-tonne E6, which later had a kid brother, the ES6, using a steel lightweight cab imported from Steyr in Austria. The ES cab is a great success on both four and six-wheel chassis. For heavier applications, however, the SP4 cab, a direct development of the B-Series cab, remains the favourite in day, rest, or fullsleeper form. While retaining the steel frame with SMC panelling it is more aerodynamic, especially in the area between the cab and the trailer, and its dash design won awards for excellence. Certainly for the driver it was one of the best dash layouts on the market. When all was well, all the needles pointed in exactly the same direction, so you could see in peripheral vision that everything was as it should be, without taking your eyes off the road.
Looking back over the two decades since ERF came up-to-date with its product engineering, there is little evidence of drama. There were no transmission disasters; no engine catastrophies; and no ownership crises.
ANACHRONISM
It could be argued that in an era of giant multi-nationals ERF is an anachronism; too small to survive, too big to be a nichespecialist. That has been said frequently over many years, but chairman Peter Foden has never accepted the notion — and he has been proved right especially by FRF's latest export order, for more than 400 heavy trucks for Zimababwe. Sound engineering, and an honest approach to the job, still has its merits in a tough marketplace.