Valuable new research findings are helping to solve the long running problem of irregular tyre wear on small diameter heavy truck tyres.

The results of the research project by RMIT Department of Aerospace undergraduate students Christos Tsangalis and Kirk Berenger were presented to an enthusiastic audience at the 2002 National Technical and Maintenance Conference in Melbourne on November 19.

Their project was funded by the Australian Road Transport Suppliers Association and was designed to improve the service life of small radius heavy vehicle tyres by developing a scientific understanding of the interaction between axle hop and tyre rotation.

They found a "Radial Stiffness Variation" of up to seven percent in a wide range of test tyres around their circumference, which means they do not roll uniformly. Each tyre also had a different radial stiffness laden and unladen.

The Radial Stiffness Variation in the tyres interacts with mass imbalance and road profile to initiate axle hop with the highest level of interaction at 100 kmh.

Reductions in irregular tyre wear can be achieved, they found, by increasing tyre and suspension stiffness and decreasing the "unsprung mass" of the axle, wheel, rim, tyre, suspension and brakes.

Other suggestions to reduce irregular tyre wear include maintaining effective shock absorbers, matching tyres by brand and diameter when used together as duals, and making sure both tyres have the same air pressure.

Australia Post participated in the project and found that tyre flat spotting from wheel lock-up during braking could start irregular wear. They reduced their trailer brake chamber size from 30/30 to 30/24 and installed load proportioning valves on the trailer braking systems to virtually eliminate flat spotting in their fleet.

The RMIT engineering undergraduates also recommended further investigation of tyre stiffness, analysing tri-axle behaviour (the worst irregular wear is usually on the centre axle in tri-axle groups) and developing a "Dynamic Tyre Wear Model".

The tyre wear project is the first of a planned yearly series of ARTSA grants for projects designed to improve safety, productivity and efficiency in the road transport industry.

The ARTSA funding initiative is also intended to encourage young engineers to become involved in the road transport industry.

ARTSA invites universities from around Australia to submit research proposals for consideration.

Further details on ARTSA research results and new projects are available on http://www.artsa.com.au. hide this