jfl ROADTEST: STRATO 26.305N16x4 TIPPER
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The 6x4 tipper has a relatively low profile, but there's a consistent demand for this class of vehicle, with a strong British presence. One of the leading UK builders is Seddon Atkinson, whose Strata 6x4 we last tested with Cummins' 110 engine. Now it's equipped with the Euro-2 M1 1—so how does it shape up?
Think of the construction industry and muckaway tippers and you probably focus on eight-wheelers, Many operators reckon that a 32-tonne 8x4 provides the best compromise between payload and on-site manoeuvrability-.
But while the eight-legger may hog the limelight there is a second force in tipping: the 6x4. The 26-tonne market is less volatile than the eight-wheeler, though sales remain tied to the fortunes of the Lics sometimes shaky construction business. Last year saw more than 2,000 six-wheelers registered, of which the majority were tippers and mixers.
It is also a sector in which the British manufacturers excel, grabbing more than 57% of the 6x4 market during 1996.
Tipper buyers can choose between a wide range of integrated manufacturers, like Iveco Ford, Volvo and Scania, and those truck builders that offer a choice of major components, such as Foden and ERE Seddon Atkinson has earned its slice of the cake by combining these two choices. As a member of the Iveco Group Seddon can call on its parent company for a well-built cab, while offering its own lightweight chassis with a choice of engines and gearboxes. Is this the way to sales success? CM put a Strato 6x4 around our tipper route to find out.
• PRODUCT PROFILE
Seddon Atkinson offers its Euro-2 Strato 6x4 with three engine ratings using Cummins' excellent M11 engine. The line-up starts at 305hp; there's a mid-range 340hp, with a topgun 380hp option. Out test tipper came with the lowest powered 305hp engine, but it still offers a healthy 1,1431bft of torque at a lowly 1,200rpm, which is more than enough for most six-wheeler operators.
The standard gearbox is Eaton's RT11609A nine-speed constant-mesh unit, though there is the option of a TS12612 Twin Splitter. However, Seddon is evaluating the 16speed synchromesh Eaton 516 gearbox from its tractor range, and our vehicle was equipped with this experimental box. Of course 16 gears are far too many for a six-wheel tipper (in fact we would question the need for the 12 of a Twin Splitter) so Seddon has blanked off the upper split on the 516 box, leaving it with eight ratios. Top is a 1:1 straight drive.
There's no crawler gear in this gearbox, but as the truck was happy to pull away in third the two lowest ratios were reserved for hard hill-climbing and site work. Our Strato would block change on occasion but was happiest running up through the gears and keeping the revs low down with bags of torque on tap.
The S16 box uses a double-H pattern rangechange shift which, though stiff, was a smooth operator. It is positive and there was never any doubt about which gear we were
in it even managed a rapid block downchange through the range-change to keep the revs up on the long climb up Edge Hill.
Roundabouts could be taken in fifth or even sixth with ease, relying on the strong lowdown torque from the Cummins Mll to haul us back up to speed in short order.
At motorway cruising speeds the truck was running almost at the top of the green band, but at 56mph the engine was spinning at 1,600 rpm, and at single-carriageway speeds it sat right in the centre of the green at 1,300rpm. Our truck had a 4.32:1 final drive ratio; if you had a lot of motorway work you could alter the gearing to suit, although if most of your work is on motorways a sixwheeler might not be your first choice of truck in the first place.
Our test tipper was fitted with an optional Jacobs engine brake and without a doubt it was the best installation we've encountered. The two-stage engine brake is controlled by two switches on the dash: when switched on it's activated by simply lifting off the throttle pedal. It was necessary to turn it off at times, particularly in urban stop-start driving, but most of the time it could be left on. Unlike some engine brakes we've tried it worked well even at low revs, so it did much better with the Mll's low-revs/high-torque characteristics than some others.
With Cummins' Celect engine management on board, cruise control is also available, The Strato uses a single toggle lever on the dash to set and resume, with speed changes possible by holding the lever up or down. All these components are held together with great style by Seddon Atkinson's lightweight tipper chassis riding on two-leaf parabolic springs at the front and Hendrickson rubber suspension for the rear bogie.
• PRODUCTIVITY With a 7.1-tonne front axle and a 20-tonne rear bogie there' plenty of loading leeway. Complete with body and tipping gear our Strato tipped the scales at 9,017kg unladen, offering a more than competitive payload potential of 16,983kg. Aggregates hauliers being paid by the tonne are going to love this one.
Out on the road the Strato performed very well. Though it is the least powerful 6x4 in the range 305hp is not bad for a 26-tanner; it's not so long ago that 305hp would have been thought more than adequate for an eightwheeler or tractor. The Cummins Mll has so much torque on offer that you can really let the revs lug down and still come back: the Strato held on to third all the way up Edge Hill to record a time of 2min 24sec.
On the motorway section of CM'S route it managed a reasonable 926mpg, falling to 8.38mpg over the tougher A-road route to give an overall figure of 8.75mpg. This is lower than the only other Euro-2 six-wheeler we've tested, Leyland Des 75300; it's also down on the Seddon Atkinson 26.275L we tried last year. But to be fair, Seddon was still evaluating the EATON S16 gearbox installation in our test truck: no doubt it would have performed better with its standard gearbox (and possibly with a revised rear-axle or top-gear ratio).
• ON THE ROAD The Hendrickson rubber suspension set-up at the rear of the Strato is the most recent lightweight version, which has done away with the 10.
(.1d central pivot point. On the A-road section If the route its did its job very well indeed, with little roll through corners and roundabouts.
However, the front end was pretty bouncy at times. It was okay on the smoother roads and motorways, but on the last stage of the circuit, heading towards Buckingham, where the road is pretty broken up, the cab was lively to say the least.
That said, it offered a secure ride with stable roadholding The steering, courtesy of ZF, was accurate and well weighted, and there was no difficulty piloting the Strato in the desired direction.
• CAB COMFORT
With the Strato six-wheeler Seddon Atkinson actually goes one better than its parent company, lveco. At 26 tonne Iveco Ford offers the Super Cargo with a raised 17-tonne Cargo cab. But Seddon borrows the larger structure from Iveco's Eurdlech/EuroTrakker range for both its six and eight-wheel Stratos. This certainly pays dividends for the driver.
The cab is spacious, without feeling too big when running on smaller roads. It offers high levels of comfort, with an adjustable steering column and full-air driver's seat, and there's plenty of storage space in the dash, on the engine cover and in the doors.
This is not the easiest cab to get into, with a tall first step fitted to maintain reasonable ground clearance. But once there it's a good place to spend the day with excellent visibility to the front and sides, and large mirrors.
)ise levels were low, even when accelerating hard. and with the windows closed the vertical exhaust never really made its presence felt. The controls were easy to find and to use, although Iveco's double stalk on the left of the steering column means that sometimes you catch the wrong one when trying for the indicators. Seddon had fitted the Cummins Road Relay screen in the centre of the dash, but it can also be set up in the headlining, along with the radio.
• SUMMARY
Seddon Atkinson has a long history of satisfying the needs of UK tippermen. The company has the knack of building tough, no-nonsense construction chassis while keeping tare weight to a minimum to help aggregates drivers maximise payloads.
The company has also walked the delicate path between independent truck builder and big corporate group member with sonic suc cess. It's taken the Iveco cab and combined it with a range of well-proven proprietary components to offer job-specific trucks to its domestic market.
The Mll engine, as we have discovered in a number of chassis, is one of Cummins' finest, offering good fuel economy with exceptional low down torque. And let's not forget that our test vehicle was the lowest powered in the Strato range.-the same truck with 340, let alone 380hp on tap, would have been an absolute flyer.
Seddon Atkinson was taking a chance by letting us loose with what is, in effect, an experimental gearbox installation, but it worked very well. It will be even better with a little fine tuning of the gear ratios to achieve optimum fuel economy.
For tipper operators looking to invest in sixwheelers the Strato has an awful lot in its favour: it would certainly be near the top of our shopping list.
by Dan Gilkes
Price: £54,114. Includes basic chassis-cab, £51,353; Jake Brake, £1,397; Road Relay unit, £621; and £743 for Eaton 516 gearbox.
Engine: 10.8 litres, 305hp (224kW). GVAA/: 26 tonnes.
Body/payload: 18.77 tonnes. Average speed: 61.07km/h (37.95mph). Fuel consumption: 32.461it/100km (8.75mpg). DRIVERS' VERDICTS In our usual quest for a second opinion we dropped in at Smith's quarry at Ducklington, near Oxford, to ask some tipper drivers what they thought of the latest Seddon Atkinson Strato 6x4...
Owner-driver Tony Robey, based nearby at Witney, drives an ERF E8.265. On hearing that the Seddon has an electronic engine, he asked whether he would still be able to do his own oil and filter changes. We said that he would, but he would probably have to rely on the dealer if any servicing was needed on the electronics. When we suggested that he could pull away in third he seemed surprised that it would cope with a full load. "This seat is [pouncing me all over the place," he commented as we drove over some rough ground. But after stiffening up the suspension he added: "That's a lot more comfortable now." And later, out on the road: "The ride is very smooth."
As we climbed the feeder road onto the A40 dual-carriageway he said: "It's got some power—I'd be at least a gear down coming up here. The gear change is quite tight but it's still very new. I like the small cab size; it's less likely to get damaged on site. It's quieter than mine. I see its got electric windows but you only need the one on the nearside. The heated mirrors adjust electrically as well," he noted. 'They'll be expensive to replace I bet. It's straightforward to sweep out but that plastic cover will tear easily and dust will get into the carpet. The bottom will get soggy too where your wet boots rub against it."
On the return journey he switched on the Jake brake just before slowing on a down grade. "Didn't that pull up well," he said, after dropping a gear or Iwo and coming to a stop at a T-junction. "I hardly needed to touch the brakes... it's better having it work oft the accelerator pedal. I've had exhaust brake buttons on the floor and they just get full of muck." Looking round the outside of the vehicle on our return he thought that the light grilles would give some orotection, but added that they were something extra to be removed if a bulb needec replacing. He approved of the threepiece front bumper and the rubber suspension at the rear, although he told us that the corner of the steel mounting plates were prone to braking on his truck.
Len Jackman drives a Foden 3275 six-wheeler for Smiths. "The front end is nice and high with plenty of ground clearance for on-site work but three steps make the access quite easy," he said as he settled in behind the wheel. "Is the Relay standard?" he asked. An option, we told him. "Owner-drivers could benefit from
he added. "The brakes are binding a bit; I can hear them squeaking," he said as we drove off the site.
After we reached the road he told us: "It feels more powerful than mine. It drives nicely and the ride is excellent although the cab rolls a bit. The steering is light and positive and the clutch, brake and accelerator placed well at a nice height. I have to lift my foot round the engine cover to operate the clutch on my Foden but this is straight up and down. Engine noise is about the same but there's less wind noise with this one. It's nice to be able to set the speed you want to cruise at and the Jake engine retarder gives more braking power than the usual exhaust brakes, which are all noise and little work.
"I think that the up-and-over action of the park brake is clumsy and it might be better on the dash," he added. "I'm not so keen on the stalks on the steering column. There are too many of them and they're too close to the rim of the steering wheel. Visibility is good across the front.
"There's plenty of room for a day cab and I like the idea of a roof hatch," he remarked. "I haven't got one on mine and it gets very hot in the summer. The trim looks substantial. The surfaces are plain—nothing fiddly. I don't think it will be any worse than mine to keep clean."
paul Worvill was driving one of Smith's few remaining Leyland Daf 17-tonners when we met, but he often drives the company's six and eight-wheelers as well. "It rides well on a smooth road," he observed, "but the real test will come over bumpy roads when it's empty. The gear lever has a nice short movement and it's a lot more positive with rigid linkage than the Fociens are with cable control."
Like the two drivers before him he kept the engine revving in the green, but as we approached the dual-carriageway he allowed the engine to dig in and conquered the hill in a higher gear still. "Pulls well," he confirmed. "I like the way the Jake comes into operation as soon as you lift off the accelerator, and it's got good brakes. The steering has a good feel and on-road at least there is no hint of understeer. The cab leans quite a lot but that can be a warning if you go into a bend a bit too quickly. I can get to all of the controls, and the instruments are clear. It's just the some as the lveco inside. It's all right."