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Toying around with a new type of dolly

It’s been hailed a major innovation, a step forward in dolly design, and late last year its supply partners won the Castrol Vecton Industry Achievement award. But, does the converter dolly live up to all the commotion? If the operators we spoke to are anything to go by, then yes, it would seem so.

Led by the ATA’s Industry Technical Council (ITC), with technical and component support from MaxiTRANS, Hendrickson, Alcoa Wheels, Bridgestone, JOST and WABCO; the ‘Converter Dolly Project’ uses a rigid drawbar rather than the typical hinged drawbar to address issues relating to brake reactivity and tyre wear.

Debuted at the Brisbane Truck Show in May 2019, it has since been trialled all over the country, with over 60 now produced and out on the road.

“It’s been used on some of the lesser road train roads, on some very rough roads and has been received very well,” said Bob Woodward, Chief Engineer at the ATA.

“Currently air suspension converter dollies don’t have a particularly good track record, so the rigid drawbar was seen as a way to address that. There had previously been some rigid drawbars in the country but there was a reluctance of people to move from tradition.”

After seeing the converter dolly displayed in Brisbane, National Customer Product Trainer at Volvo Australia, Bill Manton, was keen to get his hands on it. After a quick phone call with Woodward, the first stage of trials were underway.

Manton had big plans for the converter dolly, taking it on an 8000km trip from Brisbane to Darwin, and then back again.

“We tried the converter dolly in various combinations, pulled by a Volvo XXL. The first was being towed behind a B-double, then an A-double, then a Type 2 BAB quad, and then we swapped the combination around to a Type 2 ABB quad to move the dolly further away from the prime mover. The handing of the trailers whilst in the A-Double combination had similar handling results compared to a B-double combination, so it was very stable, especially on the narrow bitumen when you drop off the shoulder. The dolly gave no kick back force through the prime mover over big bumps whatsoever. It gave us drivers a lot more confidence regarding stability, tracking and overall trailer control in the various combinations we trialled the dolly in.

“When we had it on the BAB quad set up again, the handling of that combination was better than a normal type 2 triple combination – there wasn’t as much sway from side to side, giving a lot more control when having to give way to wide loads or on narrow bitumen,” Manton explained.

“When we did the trials, we wanted to see how it’d go. We found the rigid drawbar converter dolly was far better than a normal converter dolly. With a normal converter dolly, there are more pivot points on the drawbar so you tend to get a bit of play there. This new dolly takes all of that out of it because it’s a solid drawbar. The handling of the dolly is just incredible.”

AJM Transport was most impressed by the improved tyre wear.

Soon after, it was AJM Transport’s turn to give the new dolly a go. AJM Transport runs about 250 pieces of equipment, with its head office in Newcastle and depots in Brisbane and Melbourne. They got hold of the new dolly for three weeks or so in September 2019, taking it on a similar route between Brisbane and Darwin. It was trialled in three different configurations – an ABB quad, BAB quad and BBA quad.

Group General Manager at AJM, Dennis Roohan, said the dolly performed extremely well, most notably as part of the ABB quad.

“The drivers loved it and didn’t want to give it back, which was good, because it suffered a bit of negativity when it first came in,” said Roohan.

“It’s not something we’ve seen a lot of on the east coast. Overall, the performance was far superior to our current dollies, particularly its performance under brakes and tyre wear, which is the thing I looked at most. The tyre wear was brilliant compared to what we currently experience. When we got the dolly, it had about 30,000km on it and the tyres looked brand new. On our current dollies, at 30,000km, the tyres are already about a third worn.”

Asked whether he believes we’ll start seeing many more of these dollies on our roads in the near future, Roohan said, “It’s going to be an education process – until you talk to someone who has got it and has tried it. I know a Newcastle operator has a couple of these dollies and uses them with his A-doubles. I’ve looked at his tyre wear and it’s outstanding – concept proved. Education is the key moving forward to convert the traditionalists.”

With whispers about the benefits of the new converter dolly circulating thick and fast, Managing Director at McGrath Newcastle, Tony McGrath, decided to actually purchase two of them after seeing it at the Brisbane Truck Show. The container transport business has been using the new dollies as part of two 30m PBS-approved A-doubles, which have been on the road for around 18 months.

“I was aware of Bob pushing the barrel with these dollies. After speaking with him and thinking about it, I could see a lot more efficiency in operating these with an A-double. We have two and I’m thinking about another,” said McGrath.

“These A-doubles track a whole lot better than a B-double and because they have the EBS braking system, the brakes are better, stability is better. Every aspect of this thing is better than a B-double combination. There are not enough superlatives to describe these dollies for use in these types of combinations.”

FDWA trialled the converter dolly in August, running the 1200km round trip between Perth and Kalgoorlie.

Out in the west, bulk fuels and lubricants transport business Fuel Distributors of Western Australia (FDWA) was among the companies that trialled the converter dolly. In August 2020, the dolly was put through its paces as part of a 27.5 metre pocket road train, doing the 1200km round trip between Perth and Kalgoorlie, together with some work around town and into farms.

“It’s very stable under braking because it’s level from the Ringfeder up to the tanker. The converter dolly did what Bob Woodward said it was going to do and it did that really well. It tracked nicely on rough roads; and it didn’t duck, dive or weave everywhere, which is what other dollies can do if they’re not set up properly,” said Graham Lock, FDWA’s Fleet and Workshop Manager.

“It’s a new concept and it’s going to be hard to change people’s minds and the way they think about things, but if I was building a new pocket road train, I’d build the dolly like this.”

With the rigid drawbar converter dolly continuing to gain traction (pardon the pun), we’re seeing more operators put their money where their mouth is. Though Woodward advised there are still further technical trials planned.

“The feedback has been extremely positive. One operator in Sydney has just purchased seven of these dollies. Our ITC Chair and owner of Kelvin Baxter Transport, Kel Baxter, has also purchased one, which was delivered just before Christmas and is about to hit the road,” said Woodward.

“The rigid drawbar in the design has been designed exactly to the requirements. It’s pure and simple. When B-doubles first came along, people said it wouldn’t work – unfortunately the industry is not always readily moved to progress with the times. If we want to bring these larger combinations into urban areas, we need to make sure we’ve got everything right, including the brake performance. The design of the rigid drawbar has been a collaborative effort and without the support of our six suppliers, it couldn’t have happened.”

National Customer Product Trainer at Volvo Australia, Bill Manton, shared footage of the dolly travelling between Mt Isa and Camooweal, while set up as a BAB Quad:

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