Driving a Low Rider [Mack Metro-Liner Mixer]

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Diesel News Australia  /  May

Diesel took a trip to the Boral Enfield batching plant in Sydney to try driving a low rider. It was an opportunity to have a look at and experience the difference between the traditional agitator and Boral’s new low rider–design agitator being trialled there. This plant is one of many in the Sydney area working at full capacity as a series of major infrastructure projects have increased demand for concrete in the city.

To get a handle on the improvement achieved by Boral, Diesel took two agitators out to a job. The first was the conventional agitator built in the past, and the second was using the new design. Apart from the new layout every other aspect of the truck was the same.

Anyone who has steered an agitator at all will reaffirm the inherent instability of the platform. It’s a bit like being on roller skates, you have the feeling one false move and you will fall over. This makes the driver keep well within the parameters of safety, especially on roundabouts and other sharp turns.

Jumping into the truck for the second delivery was a complete contrast. The truck felt just like any other, it could have been a fully loaded tipper or box truck. Even in a straight line the improved stability is obvious. When it comes to corners and roundabouts the driver feels in full control.

At the same time there is great feedback from the truck. The seat of the pants feeling tells you just how the rear end is reacting. The result is a much more secure feeling at the wheel. You are no longer riding on roller skates, but a normal stable truck.

The resulting truck, from what has been a two-year process, is a revelation. The prototype went on the road in April 2016 and all of the drivers in the depot who had a go with the truck wanted to drive it rather than their own.

The principles behind this new design seem obvious when you look at the finished product. However, no one seems to have even thought about this in recent years. The question is, just what made Merv Rowlands, Boral Fleet Engineering Manager – Logistics, start thinking about this issue in a new way?

“I was visiting Mack’s Mod Centre in Brisbane, where they make all the company-specific changes,” says Merv. “I was looking at some agitators which were for us, and the nature of the suspension and the cross members I saw just didn’t look right to me.

“Within Boral Logistics, we only use Primaax suspension on all of our tippers and tankers. Then we looked at what they do in America and Europe – there’s no way they would fit air suspension on agis. Their chassis start at 9.5mm and go up, they even use double-wall chassis. They clearly see the hardest job for a chassis is to carry an agitator.

“You can see it on our older agitators. Nearly every one will have a sub-frame crack. That will disappear now, because there is no sub-frame to crack. We are now having a lot more thoughts about what we are going to do in the future.”

Read about the changes Boral made in the agitator design here.

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