A study has been reviewing and renewing the research around the concept of bringing back super singles to improve efficiency in the trucking industry.
The mass saving mathematics of moving the trucking industry back into using super single tyres instead of dual tyres on trailers are relatively simple.
With 20 tonnes on the tri-axle group on a semi trailer and 16.5 tonnes on the prime mover drive axles, if you swap out your tri-axle’s tyres for super singles, there is a tare weight tare reduction of between 300 and 600kg.
There are fuel savings to be had from both carrying less weight and the lower rolling resistance of super single tyres, and there is 300 to 600kg extra payload available. It would not be a straightforward transition; operators will have to rethink loading plans to make sure mass is evenly distributed to ensure the kingpin is carrying the right mass.
Further mass savings would be available if the two drive axles also use super singles, but current regulations limit the tandem axle group to 14 tonnes when super singles are used.
If operators could run 16.5 tonnes on a tandem axle group with super singles, there is a possible one to two tonne payload advantage available depending on where the centre of gravity is.
These figures would represent a substantial benefit for operations thinking about going to super singles, depending on the operation.
However, the regulations, as they stand today, make the use of super singles impossible, especially when running at concessional or higher mass limits. The combinations are required to have road friendly suspensions, and these suspensions must be certified under VSB 11.
One of the criteria in the wording of that rule is that the axles must have dual tyres. This means singles can’t be certified as a road friendly suspension. This legal anomaly is the key driver as to why single tyres are not being widely adopted.
This is where the roadblock exists, stopping the increased use of super singles in Australia. The asset owners of our roads, the various levels of government, have persisted with the duals requirement.
A study which has been carried out by the National Transport Research Organisation, lead by Anthony Germanchev, the NTRO Freight and Future Vehicles lead, may change the situation.
When asked, the asset owners reply that there’s a lack of data on pavement wear to have an adequate discussion about any proposed change in the rules. Their concern is that while there’s been plenty of work done overseas on super singles, none of it is using the sort of pavements used in Australia.
As a result, the authorities have been asking for a direct comparison of pavement wear between a dual setup and super singles. This has been a significant barrier to any hope of a regulation change.
The range of tyres available for the trucking industry is constantly changing and improvements around the world have seen the development of wide super singles. Unfortunately, in Australia the regulations have not changed to reflect that.
The rules are preventing the wider adoption of these more modern design tyres and prevents their use in the situations where they are can benefit productivity.
The Truck Industry Council (TIC) has been advocating for some time to remove these regulatory barriers, and submitted a proposal for a round of the Heavy Vehicle Safety Initiative funding and succeeded in receiving funding for a project.
TIC then commissioned NTRO to oversee the testing and writing of the project report. The project received significant assistance from Michelin, Good Year and the National Heavy Vehicle Regulator along the way.
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