Blending the rules, Scania‘s 6X6 Spreader

15 MinutesBy NZ Trucking magazineMarch 24, 2017

Off the shelf units are always a compromise, but Spreading Canterbury have found a standard Scania and added a bespoke bin and built an automat trailer to produce an uncompromising machine.

The new Scania and its 4-axle automat trailer look impressive, as well as purposeful. The over-width 6-wheel drive truck with its massive tractor treads looks like a G model, rather than the low cabbed P model. A glance at the P400 badge indicates it is in fact the low and short cab P model, but with three steps before the cab floor is reached, it‘s obvious that there‘s a lot of ground clearance between the sump and the Canterbury plains that this truck will spend the next decade or so fertilising.

Spreading Canterbury manager, Gavin Palmer, says that over the past few years they have mainly bought Danish-built Bredal bins, but he had some ideas he wanted to try and went to Ashburton-based Engineering Repairs 2012 Ltd to build the bin on the new 6×6. Amongst other innovations, the spreader is the first to be built with a partition forming separate front and rear chambers, meaning two different fertiliser mixes can be carried. The chambers have doors that allow either one to be spread first.

The trailer is equally uncompromising. A 4-axle Domett chassis with a heavily ribbed 8.7m automat body built in the workshop Spreading Canterbury share with their sister company Palmers Transport. Gavin points out that automat units can be troublesome, and many of the problems that occur when they‘re playing up are due to the sides spreading, allowing fertiliser to get in the wrong places and affect performance. Strong sides are the key to a reliable automat. The sides on this trailer are particularly strong because the unit is H plated and runs at 51 tonne, with about 20 tonne of trailer payload. The high productivity features means the truck can be selfsufficient in most spreading situations. The rare exception is lime; that is applied in high concentration and is required in such large volumes that the unit can‘t carry enough for a day‘s work.

What‘s more, the capacity of the unit makes backloading a viable option and both the trailer and truck bin can be unloaded into the company store at Southbridge, near the east coast about half an hour south of Christchurch.

We caught up with Gavin Palmer in Southbridge on a spring morning when he had the truck loaded with a special mix to be spread on a large broccoli crop. Over a cup of tea he explained the business and the innovative new set up.

Scanias feature heavily in Spreading Canterbury‘s fleet; in fact two Mercedes-Benz spreader trucks are the only outsiders in the 12-strong fleet. The last couple of Scanias Gavin has ordered for the spreader fleet are 6×6 units; he‘s been so impressed he‘s just ordered a third one.

Spreading Canterbury only spread on flat land, and there‘s plenty of flat land in Canterbury as we headed towards the broccoli fields with the trailer in tow.

The first surprise was tyre noise – or lack of it. We expected a lot of noise and a rough ride from the wide 445/65R22.5 tractor-tread tyres, but they were quiet and the ride was closely comparable to a Scania running on standard tyres. Gavin says the tyres usually last 50,000 to 60,000 kilometres, although they do cost about $1800 apiece. The inner tyres on the drivers are standard width models with road treads. Gavin says the extra traction provided by larger tyres was not necessary; the 6×6 Scanias have superb traction, with diff locks on all axles and full cross locking available through the transfer case, and neither of them has been stuck. A big concern is how he will recover one if it does get stuck in a soft paddock.

On-road performance is important for the Scania, because it will travel significant distances to jobs at times, as far as Rangitata to the south, north Canterbury and Arthur‘s Pass to the west; up to two and a half hours travelling time in any direction. But there will be backloads of fertiliser available for the return trip in many cases.

Engine output is modest at 400hp, but it performs more than adequately when it comes to spreading and is probably ideal on the flat Canterbury roads, even when operating at 50-plus tonne. It gets along well and acceleration is also reasonable. Gavin says the 400hp Scanias definitely outperform the 360hp units in the fleet; he would probably go to higher horsepower units, but is restricted by the P cab‘s limits and the front diff. Scania salesman, Steve Menzies, points out that without front diffs, the P model will take a 440hp engine.

As already noted, with the multi-wheel drive, the Scania‘s cab is not particularly low, even though it is a low roof P model. The big advantage to Spreading Canterbury of using the lowest cab available is that the model will fit under most centre pivot irrigators. Almost every Canterbury farm has irrigation and driving around the irrigation booms makes spreading highly inefficient. At the same time, drivers need to be aware of their truck‘s overall height; damaged irrigators are expensive to repair. The gearbox is manual; Gavin specifies manual boxes on all the spreaders and the Scania gearboxes have proved troublefree to date. It‘s a 12-speed unit with two crawler gears, but he points out that he‘s never had to use the crawler gears. When spreading he selects a suitable gear and generally leaves the truck in the same gear. It‘s important for product coverage to be consistent, which means keeping the spinners at the right revs, and spinner revs are ultimately dependent on engine revs. Depending on the product and the spread rate, the trucks usually operate somewhere between 20 and 30kph.

Once we get to the crop to be fertilised, Gavin disconnects the trailer, starts the donkey engine and raises the automat deck ready to slip the truck underneath for a refill after spreading the truck‘s bins of the specialist mix. This crop has been planted with wide gaps between the beds, allowing the wide truck to spread across the entire crop without damaging plants. Some crops are fertilised with narrow-tyred spreaders and as a spreader gets toward the end of its 10-year lifespan with Spreading Canterbury, Gavin will sometimes fit it with the narrower tyres and put it on lighter duties.

The spread rate is controlled by the on-board computer and we see a number of new innovations in play. Spreading Canterbury‘s office enters the details direct from the farmer‘s instructions. A farm map and accurate GPS coordinates allow different fertiliser spread rates be delivered in the same paddock; for example, often the volume of fertiliser required on land where effluent is spread is only two-thirds of that required where effluent sprayers can‘t reach. Accurate distribution is essential for maximum results with minimum costs and as soon as the driver hits the ‘Accept‘ button on the in-cab screen, the computer takes over most of the role.

The new bin has another useful innovation, the door between the bin and the spinners used to be manually controlled and it was possible for the driver to set it at an incorrect gap. If the gap was too wide, excess fertiliser was spread and wastage could be expensive. Now the computer automatically sets the gap, eliminating the opportunity for driver error. Onsite Gavin measures the density of the two products in the bins before accepting the job and starting to spread. The first run of product is to be spread from the front bin. It takes a while for the fertiliser to reach the spinners so he takes the truck a few metres down the row and then reverses to ensure the spread reaches the first plants. The specialist mix is spread at a low 10kph, but he points out that on the previous two days the two Scania 6x6s worked together and spread a total of 300 tonne of lime, which could be spread at about 15kph.

Four cameras help Gavin; the first two are infrared units that let him observe how much product is in each bin, even when the cover is in place. A third is mounted inside the spread shute, where it watches the product flow from the bin to the spinners; although the lens does get dirty, it only needs cleaning daily. A fourth is mounted on the drawbar to help connect the trailer, a tool that Gavin says is particularly useful, especially when the trailer is parked at an angle in a gateway off a farm race and there‘s not enough room to line the two up when reversing into the trailer.

Off-road the Scania performs well; although the land is flat, it‘s also soft, but traction isn‘t a consideration and Gavin doesn‘t need to engage the diff locks. There are hardly any tyre marks in the soil, indicating that the wide tyres reduce ground pressure significantly.

The broccoli eventually receives its first bin full of fertiliser and Gavin reverses the spreader under the raised automat to refill the empty bin. The donkey engine on the trailer is fired up and the belt rolls product into the bin. Scales between the bin and the Scania‘s chassis let the driver know exactly how much product is on board.

Keeping spreaders clean is an important task. The bin on the new truck is made out of stainless steel and although the outside is painted, the inside is left unpainted and is super easy to clean. Fertiliser sticks to paintwork and unless it‘s regularly cleaned off, it can damage paint. Gavin has had a new treatment applied to the paintwork, including the painted wheels on the Scania. Although it‘s early days, he says it‘s easy to clean using just a hose, and may well be the long-term answer.

Gavin can‘t find a bad word to say about the Scania; he points out that even in Sweden they‘ve been helpful and the new truck is a special build, factory painted. He does get a few extras, including a longer dashboard that allows more accessories, such as camera screens and the spreading computer to be easily added. He reckons he will be with the brand for the foreseeable future, especially if they can squeeze a few more horsepower under the cab. Even with the low-mounted muffler, there‘s plenty of ground clearance.