These tests set the tipper norm
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Bill Brock ono Tim Blakemore take five vehicles over our rough road/on-highway route, use their results to compare with tests in future CV issues. Photos by CM photographers
TO GIVE a better comparison between vehicles, we introduced a combined rough road/ on-highway tipper test route last year.
This week we conducted an eight-wheeler group test to provide onand off-site performance by which future test vehicles can be compared. Body size and engine power varied between vehicles, but all were loaded to the full 30 tons gvw.
Fodens borrowed a 7.0m (23ft) wheelbased RR 27/30 Haulmaster, from haulage contractor Alfred Hymas Ltd of Harrogate, with almost 36,000km on the clock. Three engine options are available with this model. Ours, fitted with the Rolls-Royce Eagle 265L equipped with a viscous fan to provide 6.4 kW/tonne (8.83bhp/ton), was nicely run in.
The 65 tilt cab, of composite construction using grp over a steel space frame, retains the 'distinctive split front screen but includes such modern safety features as antiburst door locks, a steel bulkhead, and tinted laminated glass.
Two steps placed forward of the wheel arch aid entry to the high mounted cab, and grab handles each side of the door opening provide added purchase.
The layout inside the cab is. comfortable but a little untidy and the driver's suspension seat is fully adjustable. Adjustment to the steering wheel rake can be adjusted for the stouter driver, but wasn't needed by us — yet!
A moulded centre console, containing document holder, vacuum flask recesses and radio, make a feature of the high engine cowl which divides the cab into two parts Directly in front of the steering wheel, a large instrument binnacle displays an array of meters and gauges in a random order. Over the 200km (124 miles) of our test route, the Haulmaster returned an overall fuel consumption of 57.6Iit/ 100km (4.9mpg), but good off-road ride and handling performance contributed to the high average speed of 39.9km/h (24.8mph).
Semi-elliptical tapered leaf springs with trailing shackles and shock absorbers on the front bogie were well matched by the non-reactive rear tandem bogie's rubber suspension, giving a smooth ride and good resistance to roll.
Already specified on the sixlegger. Fodens intend to stan-clardise rubber suspension (made under licence to Rydwell) for the 8x4's too.
Integral steering power assistance had suficient -feel" and was without any violent kick-back through the system.
Forward visibility is good despite the old-fashioned split screen, but the rear-view mirrors became dirty quickly. When clean they compensated a little for the poor rearward vision on the off-side.
Initially, gearchanging tended to be notchy, The Fodens eight-speed rangechange box includes several unmarked overdrive ratios, but these are not fully stressed gears and should not normally be used.
Once we had become used to the unusual gate positions there was no problem in making clean changes of two or three gears at one go while following the prescribed method of clutch operation.
We never experienced any problems with the brakes, even after negotiating some of the wetter parts of the cross-country section. For normal use the exhaust brake, operated by the first inch of movement of the foot brake, was an asset which gave a check to the vehicle speed on running downhill, while leaving the main service brakes cool and ready for heavier braking.
Front-end tipping gear fitted to the Wilcox grain body is made by Hydro-Hoist of Croydon, which is a company 75 per cent owned by Edbro. Since the merger under the IVECO banner, it now seems easier to get a Magirus Deutz model for test than a Fiat. Power for the 232D30FK rigid eight-wheeler is provided
by an 11.3,1itre (690cuin) air'cooled V8 engine of modular design, with an output of
170.5kW (228.5bhp) at 2650rpm, while the relatively low torque of 722Nm (530 lbft) occurs at about 1400rpm.
The ZF six-speed constantmesh gearbox was fitted with a GV80 front-mounted splitter giving a total of 12 forward gears while the rear hub reduc
tion axle with a relic, of 7.091 is the lowest of the three on offer.
' Rubber mounts are provided at the front of the all-steel cab, with rubber shearing buffers and shock absorbers at the rear. Just 25 of tilt is said to give adequate access to the engine below, but we weren't able to verify this as the hydraulic pump handle had been removed from the stowage clip inside the cab.
Again five steps in front of the wheel arch are provided for cab access, the first of which looks somewhat insubstantial for such a vulnerable position.
On our test vehicle it had already suffered through a knock. Internal fitments are mainly purely functional.
The rubber floor mats, with ribs running towards the door, finish flush at the opening without a lip — ideal for hosing or sweeping out. Cloth seats are inducted but don't have individual suspension. Instrumentation is well laid out with most of the gauges visible through the steering wheel.
The riveted and bolted construction of the ladder-type chassis included too many superfluous holes for good engineering practice. A Wilcox aluminium body and Edbro front end tipping gear fitted neatly into position, allowing a reasonable clearance for the fuel tank filler.
To begin with we were unaware of the splitter — operated by moving an unobtrusive collar on the gearstick. Its use did allow a much finer control over the engine's working rev band. Although the steering has integral power assistance, like the Foden, more effort was needed. Clutch and throttle pedals were also heavy.
Torsion bar stabilisers restricted the roll, and directional stability was quite impressive. But the ride became very bouncy at times over the rough road, particularly wearing in the absence of a suspension seat.
A corner window on the rear cab panel gave good rear vision — a definite advantage at acute road junctions.
Over the roughest crosscountry section the benefits of the rear two-spring bogie articulation, keeping the wheels in contact with the ground, was evident under quite extreme conditions. Inter-axle and crossaxle diff locks added to the traction performance when the going became particularly, sticky.
The biggest problem we had was controlling the temperature inside the cab. The level of heat emitted from the engine oil heating system seemed to change more or less in sympathy with the load being applied.
Overall the Magirus seemed quiet, worked well, and is a nononsense vehicle. In 1979 Leyland Vehicles took the lion's share — 25 per cent — of the eight-wheeled rigid market, with the Routeman chassis proving particularly popular with tipper operators, many of whom are owner-drivers. To a casual observer this may be surprising for the Scammell cab is old-fashioned and has a definitely spartan interior, while both engine options, TL114 and Rolls-Royce 220, are relatively low-powered.
But a closer look at the vehicle's specification will reveal what attracts tipper operators to it. Unladen weight is a critical factor, and the Routeman is the third lightest 8x4 after its stablemate the Octopus 2 and Volvo's F7.
It is among the least expensive, but perhaps its most important asset is its reputation for reliability.
Our test vehicle came from Greenham Sand and Ballast of Feltham and belonged to Alen Kovak, an owner-driver with two Routemans.
His first vehicle had the Rolls engine, but on the latest one he had decided to try Leyland's turbocharged 680 — the TL11A. The gearbox was David Brown 64/28 six-speed constant mesh (no longer available) with an overdrive top gear ratio which coupled with the 6.933:1 rear axle ratio gave the Scammell a maximum geared speed of only 84km /h (53mph).
. Alen told us that all his work was local so the low maximum speed didn't worry him — even so the gradeability was no better than 1 in 5.1. Part of the reason for the chassis's light weight is the distinctive grp Scammell cab which, of course, is lighter than a steel cab but also saves weight by not having a tilting mechanism.
Access to the engine is gained via the engine cowl dividing the dab in two, but access to the cab isn't easy. We found that we could only just reach the grab handles on the door and door pillar, and the one and only step was too far off the ground for comfort and safety.
Once in the driver's seat the impression was of a spartan interior with the minimum number of instruments and controls — very different from most modern vehicles.
There were just three gauges on the dashboard — air pressure, engine oil pressure and coolant temperature — alongside the speedometer, no rev counter and not even a low oil pressure warning light.
Without a rev counter it was impossible to tell at what speed the engine was working, but we were surprised at its ability to pull from low revs. Its flexibility over most of our route compensated for any lack of ratio choice but the Routeman did struggle a bit on the offroad steep gradients. This was probably the main reason for the low average speed of 35.6km/h (22.1mph). On one of our circuits we were delayed for a long while on the road section just outside Bagshot by a fully laden Army tank transporter moving at a painful 10mph. We discounted this circuit when calculating average speed but, since the Scammell didn't have a fuel flowmeter, there was no way of telling how much extra fuel was used in this hold-up.
Many tipper operators prefer a fiveor six-speed gearbox to 'a multispeed version, and this is another point in the Routeman's favour. The selection pattern on the David Brown box, which won't be offered in the future because the company has ceased production, was a little confusing though with fifth being where you would expect to find sixth and vice versa.
In many respects the Leyland is a complete contrast to the DAF we had driven the day before, particularly with regard to steering and suspension. While perfectly acceptable, the Routeman's power steering was fairly heavy and the firmness of the chassis .suspension was accentuated by the lack of suspension seat. But the firm suspension provided little noticeable body roll when cornering.
. There's an interesting contrast, too, in the designs of the rear bogie suspension, with DAF using the springs to locate the axles while Leyland has slipper ended springs and radius rods to keep the axles in the right relative positions. Both suspensions are "two spring" — that is one spring each side of the chassis. DAF's eight-wheeler is manufactured specifically for the British market. Some may be seen on the Continent, but always in right-hand-drive form.
Over our tipper test route, which combines 16km (10 miles) of road section with 4km (2.4 miles) of off-road work, the FAD2305`s specification proved to be well-suited to British operating conditions, achieving a respectable average speed and fuel consumption..
We aim to complete ten circuits of the route, a total of 200km (124.3 miles), to mak the results as accurate as possible and usually, by the fifth circuit, the trip times have become consistent. But unless a flowmeter is fitted, it's impossible to tell how much fuel consumption is fluctuating from one trip to the next.
The DAF was fitted with a flowmeter and it was interesting to see that the two worst consumption figures came from the first trips in the morning and the afternoon, probably because of the drag from the cold transmission oils on those occasions. There are two steep gradients on the off-road section and a lot of twists and turns which explains why the fuel consumption was down to 3.0mpg here, whereas on the roads around Bagshot 6.5mpg was the norm.
In the eight-wheeled chassis, DAF's ubiquitous 8.25-litre engine is rated at 169kW (230bhp) which seems to be about the right power for a 30 ton-gross tipper, giving a power-to-weight ratio of 5.54kW /tonne (7.57bhp/ton).
Operators who do more road than site work may feel that the maximum speed of 90km /h (56mph) is a little on the low side, but there are unlikely to be any complaints about a gradeability as good as 1 in 3.3. If the optional rear axle ratio of 5.76:1 is specified the eightwheeler can climb a 1 in 3 hill but its maximum speed is then restricted to 80km / h (50mph).
The worst hill on our route steepens suddenly and a fast downward change is needed, skipping at least one gear, if you want to avoid coming to rest. Here the DAF's hill-climbing ability, combined with the easy to use ZF range change gearbox, was a boon. If any criticism is to be made of the box it could only be that gearchanging is marginally slower with it, because of the synchromesh, than with a constant-mesh variety.
It was certainly a pleasure to find a ZF gearbox with a conventional H shift pattern.
DAF has been -criticised in the past on the lack of space between the large diameter. steering wheel and the driver's seat on 2300s and 2100s. These complaints haven't gone unheeded, for since January this year Sable suspension seats, which can be moved further backwards, have been fitted.
For a tipper driver who may spend much of his working day driving over rough ground, ride quality is important. We found that the DAF's chassis suspen
sion and suspension seat between them absorbed most of the bumps, leaving us fresh at the end of the 124-mile test.
But a disturbing characteristic of the comparatively soft chassis suspension was the amount of body roll on corners.
The Wilcox alloy body didn't have high sides so it wasn't caused by a high centre of gravity and indeed one wonders how much worse the roll would be if a high sided body was fitted. Perhaps anti-roll bars would be the answer.
One of DAF's best points is the power steering which is very light (some may argue too light), and positive, and suffered from no kickback at all, even over the roughest ground.
We also liked the capacious stowage space in the cab; the forward set mirrors that stayed fairly clean throughout the test; and the downward facing mirror on the nearside that greatly reduced the size of the "blind spot" next to the nearside front wheel.
THE 30-240 MAN 8x4 fitted -with a Wilcox grain body was loaned for the day by W. Porter of Stamford, Lincolnshire. A rear axle ratio of 5.26 to 1 has just become available with this model and should give better motorway economy if the extra speed is not fully used.
On the CM test route it may have produced better all-round results with one of the slower. ratios, but nevertheless gave a good account, returning 52.7 litre/100km (5.35mpg) at an average speed of 39.4km / h (24.5mph).
The body, full of grain, produced a higher centre of gravity than with the other vehicles loaded with gravel. In consequence, in the absence of a front anti-roll bar, roll from within the cab was more noticeable.
Despite this, the journey times were good. Engine power rated at 5.8km/tonne (7.9bhp /ton) had a part to play in this but was equally matched by the specification of the ZK AK6-90 six-speed constantmesh gearbox, equipped with a GV90 splitter to give 12 forward gear ratios in all, which allowed the vehicle to be driven so that the engine speed remained at around maximum torque for much of the time. For clean downchanges. though, it seemed to give a better result if in the low ratio
The all-steel day/ rest cab is equipped with a wide, folddown bunk and curtains all round. An Isringhausen suspension seat made by the German company at Milton Keynes, is included as standard, but does not adjust automatically to com
pensate for driver weight.
Access to the cab is easy and the driving position comfortable. Such instrumentation that is included is placed symmetrically and easily read. Ample power assistance made light work of the steering both on and off the road, without any noticeable hunting about the centre position. Internal cab trim is pleasing and easy to clean.
The small window behind the door limits rearward visibility on the offside. Two glove pockets, one on the dash, the other in the head.er rail, are provided for stowage of drivers' paperwork, and so forth. In front of the passenger seat, also on the fascia, a grab handle is located as an optional restraint.
Other items include a radio as standard, two-speed heater and courtesy lights. The handbrake control is located on the fascia so leaving the floor area clear.
As with the Magirus Deutz, operation of the exhaust brake pulls back the fuel rack to cut off the feed, but unlike most this one appeared to have some bite and held the vehicle's speed steady on the hot too steep downhill descents.
We tested a 30-ton MAN tipper in 1977 and managed, without any special effort, to rip off the silencer, which stuck out between the front-steered wheels. Alas the fault remains.
Fitted with an air-operated lockable interaxle differential and cross-axle difflocks the MAN is intended to go into and get out of difficult conditions.
Our vehicle did just that, but left the silencer buried in the mud.