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SMOOTH SOPHISTICATION

24th March 1988, Page 40
24th March 1988
Page 40
Page 40, 24th March 1988 — SMOOTH SOPHISTICATION
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Pulling away from rest in town does nothing to detract from this air of smooth sophistication. The servo-assisted clutch (with an asbestos-free lining) is light and bites smoothly from low engine speeds. With so much torque available, the vehicle has no trouble in pulling away in the third of the gearbox's eight main ratios. In town traffic, however, it is a lot easier with a vehicle as high-geared as this to pull off in 2 low, skip to 4 low, split across the range change to 5 high, and then take whole gears.

MAN mounts the shift mechanism for the big ZF gearbox rigidly on top of the engine, and the gearlever stays in place there when the cab is tilted. Such a mounting obviously increases noiseinsulation problems, but ensures that the often-troublesome double-H shift mechanism is unusually positive here.

With so much power and, crucially, so much torque available, traction could well be a problem on a 4x2 tractor pulling an all-up weight of 40 tonnes. As it was, on a filthy day of blizzards, with the temperature hovering around freezing and ice and snow on the roads, we lost traction only twice in some 200km. Once was on a snow-covered parking place where the vehicle was left over lunch and the warm tyres melted themselves into depressions. That was solved with a bit of fore-aft rocking and the cliff locked. The other was when we were trying acceleration runs on a streaming wet road, and the Continental EDT tyres could not find enough grip for full power in a 3 high start. Even with wheelspin to begin with, the 19.462 recorded an acceleration time of just 90 seconds to an indicated 1001m/h.

With such treacherous surfaces, the vehicle remained under perfect control on downgrades as well. The exhaust brake, triggered via a well-placed button, is impressively effective even at low revs. At higher engine speeds, the brake is as good as the one on the new Volvo F16: the only disappointment came as revs dropped off and all braking effort disappeared suddenly at just below 1,500rpm.

As would be expected from the power and torque figures, the performance of the 19.462 is really impressive. With the 3.36:1 drive-aide ratio, the big MAN is geared for the German 801trniti motorway limit, where it is spinning at 1,200rpm in 8 high — right at the peak of the engine's torque curve. That gearing would give an engine speed of 1,440rpm at the British motorway 60mph speed limit, just tending towards the top of the solid green sector of the rev counter.

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