In the South African study, two long-haul trucks were used in evidence-based eco-trials over the duration of one week. Wits University took to the driving seat to measure the performance of green low-rolling-resistance tyres against a set of conventional ones. 

While these eco-tyres may be the new kid on the block in green driving, the results will ensure they are readily accepted in the trucking game with drastically less CO2 emissions, fuel savings of more than eight percent and the ability to unlock 40 percent more profit for the transporter. 

Rolling in the green

Over the week of the trials, one truck was fitted with a set of conventional tyres and the other, with green tyres while both were put through their paces at the Gerotek test facilities in Tshwane, Gauteng. The tyres were then swapped on the vehicles to ensure the same result was obtained.

As each vehicle was kept to a steady speed of 80 km/h by drivers who took 10-20 minute breaks every two hours, the Wits researchers from the School of Mechanical, Industrial and Aeronautical Engineering carefully monitored several datasets, including fuel efficiency, coming from the vehicles. 

“The problem that tyre companies historically have encountered is getting the green truck tyre accepted in the industry because fuel consumption is dependent on so many variables,” said Wits Professor Frank Kienhöfer. “You need to normalise the driver behaviour, wind speed, the vehicles, the routes, all of which has meant that tyre companies have struggled to prove to the industry that tyres can make a fuel-saving difference.”  

Verdict on tyres on trial 

He explained, “What makes these environmentally friendly tyres different is the materials are slightly different; they use silica instead of carbon black as a reinforcing filler and the different tread pattern causes less deformation. There is less energy wasted than turning the tyre which in turn, manifests in a lower operating temperature. In this respect, green tyres are, in fact, safer and less likely to blowout due to overheating.”

On assessing the results, the Wits team found that, at 80 km/h, the long-haul truck burnt eight percent less fuel on the green versus the ordinary tyres. “This means eight percent less CO2 was emitted into the atmosphere from a single truck,” added Kienhöfer. “Implement this on all long-haul transport trucks in South Africa and this green intervention could make a significant difference.”

“We were thinking the difference would be more in the ballpark of five to six percent so there appear to be massive advantages of using the rolling-low-resistance tyres,” said Rehaan Abdulla, a Wits MSc student involved in the study. 

Even though green tyres have a 25% shorter lifespan than their traditional counterparts, they still hold the edge when it comes to financial benefits to transport companies. Kienhöfer pointed out that such savings on fuel could increase profits by 40% in the low-profit margin transport business, even when calculating in the tyres’ shorter lifespan.  

Pivotal motion in partnership

Working under the umbrella of the Centre for Sustainable Road Freight South Africa, the study included participation by Michelin, Iveco, Afrit, Lafarge, Total, the Council for Scientific and Industrial Research (CSIR), and Cambridge University. Wits oversaw the trials, ensuring that everything from booking the track to setting up the test protocols. 

A special note of gratitude was expressed to the Royal Academy of Engineering who partially funded the study under the Industry Academia Partnership Programme. 

Green cars and green energy may not be new but what is new and needed is the commercial enablement of such solutions for broad industry adoption and application. Studies such as this are pivotal in exploring potential pitfalls and equally, plausible wins for the planet and all people. 

“Green tyres are in pole position to accelerate green driving which is key is for the transport sector to propel momentum forward to positively impact climate management,” concluded Kienhöfer.

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