Command performance

As leaders in Performance-Based Standards (PBS), the motivation of the Smedley’s team remains the same: Achieve innovative solutions that anticipate, meet, and supersede real issues faced by the industry.

Since its establishment in 1931, Smedley’s Engineers has always worked hard to expand its services and expertise, as well as its reach to support our industry right across the nation.

Being the first end-to-end PBS consultancy couldn’t have been possible without the diversity and specialised skillset of Smedley’s workforce. Managing Director, Robert Smedley says, “Our team members are in touch with the industry, with close to 100 years in combined heavy vehicle experience, and a mix of backgrounds including heavy transport businesses, truck manufacturers, trailer builders and OEM component suppliers. “
While most PBS consultancies only have narrow industry experience, the dedicated team at Smedley’s Engineers have backgrounds from right across the industry, providing the experience and know-how required to identify and resolve issues for their clients.

Some instrumental members of the Smedley’s Engineers team talk about their experience, particularly with PBS and the benefits of super single tyres.

Andrej Bucko, Senior Engineer


A graduate of Monash University in 2011, Andrej Bucko joined Smedley’s as a Senior Engineer in 2018 after almost a decade at ARRB where he honed his skills in the field of vehicle dynamics. Andrej is an accredited PBS assessor at Smedley’s Engineers. Throughout his career, he has completed hundreds of PBS assessments and has also developed vehicle simulation models.

David Clark, Senior Engineer


With both an engineering degree and business management qualifications to his name, David has been at the forefront of cutting-edge engineering since 2012. Growing up around the trucks and machinery of his family’s transport business, he later began his career in the F1 & Special Builds division of one of the world’s leading high-performance automotive cooling specialists. In 2015, he moved across to the heavy vehicle industry as a mechanical engineer. His extensive experience in brake, noise and roll-over testing has driven his enthusiasm to find new innovations in vehicle performance, and he feeds off the excitement, expectation and pressure that comes with applying and assessing new technology. His passion for developing vehicle components that enhance safety, output and efficiency has now been matched by his drive to build strong relationships with his customers and work with them to achieve their desired outcomes.

Dion Simms, Senior Engineer


Dion Simms is an Automotive Engineer with a background in OEM passenger vehicle architecture and motorsport. His career has included roles at Volvo Polestar Racing and Ford Motors, but a keen interest in heavy machinery saw him join the Smedley’s team in early 2021: “I came into this project to coordinate the physical testing and to conduct the data logging and reality capture.”

Jackson Heil, Senior Engineer


Jackson Heil has been in demand as an innovative mechanical engineer since graduating from Swinburne University in 2013. With a background in heavy vehicle manufacturing, Jackson joined the Smedley’s team in 2018, passionate about the technical side of the industry and all the ‘behind-the-scenes’ elements of design, innovation, and manufacturing to meet PBS requirements. He is involved in PBS certification and access space, communicating with the manufacturer, the operator, and the road manager to make the on-road stuff happen.

On the road again with Smedley’s
Currently and for over the last two years, one of the big goals for the team at Smedley’s Engineers is getting super single tyres broadly into PBS at higher masses. Super single tyres through PBS at masses equivalent to dual tyres are a game-changer in the industry, resulting in higher payloads, better fuel efficiency, improved tyre life and decreased tyre costs, as well as better environmental outcomes.
Robert Smedley says, “This is one of the single biggest things the government and industry can do to reduce carbon emissions in a long-haul country like Australia, and it could be done right now.”

Earlier this year, Truck Industry Council (TIC) and the Australian Road Research Board (ARRB) engaged in pavement wear testing on new ultra-wide tyres (super singles). TIC stated that test results would provide the scientific evidence required to develop a case for increasing mass limits for heavy trucks and trailer axles fitted with wide-base single tyres. Robert Smedley worked closely with Chris Loose in getting the funding proposal to happen, as part of this, Smedley’s provided data to support the safety benefits that were used in the submission for the funding.

Glen Fulton, Logistics Fleet and Equipment Manager at Visy, previously spoke with Trailer in late 2020 about an order of 30m PBS A-double combinations, a unique design. He said these trailers were specifically designed to carry an awkward commodity: paper reels, which, when loaded, stand at three metres high and weigh three tonnes each. He also mentioned this design was a challenge due to the need to meet static roll threshold or high-speed off-transient manoeuvre test requirements for PBS.

Moving to super singles significantly improved the performance of the A-doubles which typically get much lower payload heights than B-doubles. In 2020, this was also the first time a Concessional Mass Limit (CML) of 17 tonnes had been approved for PBS operation of a tandem axle dolly with standard 385/65R22.5 (low profile) super-single tyres.
At the time, this was a game-changer for the industry, along with wide-track axles and suspensions which hadn’t previously been used on trailers in Australia. This enabled the team at Smedley’s Engineers to achieve an unprecedented level of stability required for high payload height loads.

Since then, the team has been able to achieve 27 tonnes on quads with super singles and has more recently been involved in testing to get 22.5-tonne on tri-axle groups fitted with super singles.

Reflecting on the consultation process between Smedley’s Engineers and Visy, Smedley’s engineer Jackson Heil describes it as being just like any other project.

“Generally, we will speak with the customer about what they want to begin with and where they want to transport their freight,” he says. “It’s from this point we look into what type of combination is best going to fit their needs while delivering the best outcome on road networks around the country. Once we compile our recommendations, we discuss everything and move forward with the customer and manufacturer to deliver the PBS outcome they are after.”

In terms of super single testing and validation, Robert and the Smedley’s team found the super singles surprisingly performed worse in Low-Speed Swept-Path (LSSP) when modelled in the computer simulation.

“This led us to do field testing to see if this was the case in reality, and it was.”, he says. “Lots of PBS assessors in the past have ‘wrongly’ assumed that super singles got the same LSSP results as duals, but they don’t. We were initially surprised when this was verified in the field tests. We are happy to say, though, that we’ve developed a solution in conjunction with Hendrickson and MaxiTRANS that overcomes this issue.”

Andrej explains the difference in LSSP occurs when super singles are fitted to self-steer axles. He says, “The steer axles don’t turn as well with singles as with duals. So, swept path was an issue with the Ron Finemore combination but not Visy, which did not have self-steer axles. Additionally, we expect that the amount of difference between duals and singles in swept path will be dependent on the make and model of self-steer axle so a solution will have to be calibrated individually to a specific self-steer axle model.”

Dion notes how it’s easy to assume that, at low speed, tyre dynamics are inactive and different configurations will not have a significant impact on swept path outcomes.

He says, “The kinematic geometry of the same self-steer axle fitted with duals or fitted with super singles does differ and that kinematics really matter when you’re pushing for the best outcome for a given level of road network. After seeing the results vary in response to the parameters in our test schedule, I know I came away with a reinforced respect for the quality of the ADAMS modelling we’re producing, and I wasn’t alone. PBS is seen as simulation centric. It was valuable to close the loop and see those simulations reflected in real-world results.”

Andrej explains how the Visy A-double combination carried indivisible loads which provided a unique challenge. “Typically, if a vehicle fails SRT or HSTO the solution is to lower payload height until a vehicle passes those standards.”, he says. “However, as the load is indivisible this was not an option. Super single tyres combined with wide axle track width, wide suspension hanger track and high roll stiffness suspension allowed us to meet the required load height.”

Getting tyre data is also sometimes an issue. Andrej says,” Not many manufacturers perform the tests necessary for assessors to model super single tyres so there is a lack of data, especially compared to more common sizes like 11R22.5. However, the National Heavy Vehicle Regulator have announced that the PBS system will be moving to a standard or ‘generic’ tyre where a single dataset will be used for a specific tyre size. Therefore, make/model restrictions for super singles could become irrelevant.”

Since these vehicles have rolled out, Smedley’s Engineers have observed improvements to heavy vehicle route access. Jackson says, “As the road networks slowly improve, we have started to see better access being granted which has opened up other lanes for the 30m A-double that couldn’t be done to begin with.”

For more information about the Smedley’s Engineers team, PBS and super single tyres, visit www.smedleys.co.

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