Running a modern transport operation in the Northern Territory often means going for even bigger trucks. Bob Holt, from Katherine, is one such operator, with plenty of stories to tell and still running big trucks on a daily basis in the modern business environment.
In 1967, Bob bought the first Kenworth in the Northern Territory. He had been using a Bedford, with a carrying capacity of 12 tonnes, until this point. He had also been pulling a dog trailer with another 12 tonnes. This had been followed by a petrol powered Ford, an International bought secondhand out of Alice Springs then followed.
Bob now runsx two Volvo prime movers, the older truck is a tri-drive, the newer Volvo FH is a twin steer 8×4 prime mover. Both have identical engine rating and axle ratios, and 4.55:1 diffs on all the trucks give them 1,400rpm at 85km/h. 600hp is the rating Bob chooses for his trucks.
“What’s the saying?” says Bob, “The more fire, the more fuel. We used to pull these trailers with 350hp. “We were talking about the new low gear I-shift from Volvo. They have always lacked a low gear. That’s why a lot of operators went to the Roadranger instead. Now with these two new low gears you can run a taller diff, then you can run the engine at around 1,300rpm and you are saving fuel again.”
The trucks are limited to run at 85km/h and Bob reckons he will get 1.25km/l going up to Darwin on a 644km round trip, with a combination which runs at 142 tonnes. He reckons this is a lot more economical than some other operators.
“While you’re saving fuel, you’re saving everything else too,” says Bob. “I’m always trying to squeeze more economy out of the truck. The time difference when you are running at 85km/h is nothing. In 322km to Darwin, the time difference is 15 minutes at the most. It’s only a couple of sets of traffic lights’ difference. At that speed it’s also so easy to drive.”
Bob has always used Azmeb Trailers, side tippers designed for the tough jobs. The driver pulls into the yard and in less than ten minutes there are 105 tonnes of sand on the ground, ready for processing. This needs two passes – the first to tip trailers two and three, and then a second to tip the front trailer.
By running both a bogey and tri-drive, Bob is in a situation where he can compare the configurations in a like-for-like scenario.
“You can get the same rating on a truck whether it’s a tri-drive or a twin-steer bogie drive,” says Bob. “Once, we even had a tridem truck, two drive axles and one lazy and that wasn’t any good. We were getting stuck all of the time and it was only marginally cheaper than a tri-drive truck.
“We have had tri-drives, but we have chewed tyres off the front drive axle. Any troubles are with the front diff – it’s copping a hammering. A bogie drive truck eliminates all of that. Capital wise there’s no advantage, there’s an advantage of about 750kg payload on the tri-drive. The twin steer is hard on steer tyres and when compared to the tri-drive, which is like driving a Commodore, it nods and comes down hard on the second steer axle.”
Across the different brands of trucks Bob has bought, the kind of work he uses his trucks for has seen him acting as a guinea pig for a number of products. The application has taken trucks into unknown areas.
One truck which consistently twisted drive shafts scared the living daylights out of an overseas engineer who was riding on the chassis to see what was happening as the truck climbed a short climb out of an oil depot. He actually jumped off a moving truck into traffic to avoid the twisted mess. The solution was to use a shaft from a competitor brand.
Another engineer sustained a badly injured hand after putting it onto a diff at the top of a grade. Bob was too late in warning him and he lost a lot of skin on the well-overheated axle. The diffs turned out to be great for the job, but needed much increased cooling to work in the Territory.