In real-world operation, 100 Mercedes-Benz Econic refuse collection vehicles with shallower axle ratios returned a 2.4% fuel saving.

AMPTHILL, UK, May 14th 2025 – Allison Transmission – a leading designer and manufacturer of conventional and electrified vehicle propulsion solutions and the largest global manufacturer of medium- and heavy-duty fully automatic transmissions for commercial and defense vehicles – and leading UK waste management company, Biffa, have revealed an average fuel saving of 2.4%, following the specification of different refuse vehicle axle ratio settings.

In 2022, Biffa switched its orders of Mercedes-Benz Econic refuse collection trucks with 270-, 300- and 350-horsepower engines from the standard 6.84:1 axle ratio to a shallower 6.0:1 ratio, also offered as a factory-fit by Mercedes-Benz. This followed a simulation exercise by Allison Transmission using its industry-leading iSCAAN software program, which identified a reduction in fuel consumption of up to 3%, in addition to lower cab noise. Based on this advice, Biffa made the decision to order all replacements of this vehicle type with the new 6.0:1 ratio.

The positive fuel saving effect has now been validated on 100 Mercedes-Benz Econics over 700,000 miles of real-world operation in trade and domestic refuse collection in the UK. The achievement of 2.4% fuel saving equated to a cost saving of 2p per mile and a total of £14,000 for the miles travelled in the study.

“Biffa’s robust data collection and analysis over the past couple of years has cemented the findings of our initial research: that it is possible for commercial vehicle fleets to cut their fuel consumption by requesting different axle ratios to those routinely offered on new vehicles,” said Nathan Wilson, Account & Area Sales Manager UK & Republic of Ireland at Allison Transmission.

“Historically, a deeper axle ratio setting has been the default selected by OEMs to provide the best gradeability for a 30 percent and above incline, an extreme that is rarely encountered on UK roads. A shallower axle ratio can be selected to provide better fuel economy without negatively affecting the vehicle’s launch gradeability or productivity, thanks to Allison’s Continuous Power Technology^TM, which nearly doubles engine torque at launch and delivers power to the wheels without interruption when shifting,” concluded Nathan Wilson.

“This is one of many successes resulting from our consultative relationship with Allison Transmission to optimize our vehicles’ drivetrains, with the aim of reducing fuel consumption, CO2 emissions and total cost of ownership,” said Darren Judd, Biffa’s Head of Fleet Development. “While 2p per mile saving does not sound like much, over many vehicles and years it all adds up to be a significant amount.”