Study shows soil compaction superiority of IF tyres
A French study has demonstrated the effectiveness of Improved Flexion (IF) tyres at reducing soil compaction compared to a set of caterpillar tread tracks. The study, organised by the French National Research Institute of Science and Technology for Environment and Agriculture (IRSTEA), measured the soil compaction rates on a 3.5 hectare plot of farmland after a loaded combine harvester fitted with three different mobility options – a set of Michelin CerexBib 800mm IF tyres, a set of CerexBib 900mm IF tyres and a set of three 760mm roller caterpillar tread tracks – passed over it.
On soft ground, the combine harvester fitted with the three small caterpillar tread tracks increased the hardness of the ground by 55 per cent compared to the control area. When fitted with IF 900mm tyres inflated to 1.4 bar, the harvester increased ground hardness by only 46 per cent, or nine per cent less than the tracked machine.
“The objective of the study was to measure the difference in compaction between the two technologies,” commented Mike Lawton, commercial director of Michelin’s Agriculture division. “Farmers and contractors are under increasing pressure to increase crop yields year after year and so they want to make sure they are using a mobility solution that offers the lowest compaction rates.”
On hard ground, tests showed the caterpillar tracks exerted uneven pressure on the ground, with peaks reaching levels up to two times higher than those obtained with IF tyres, which distributed the load evenly over its entire footprint.
The combine harvester fitted with 900mm IF tyres, inflated to 1.4 bar, evenly spread the pressure exerted on the ground, calculated at slightly over 4 bar. With caterpillar tread tracks, the combine harvester exerted uneven pressure on the ground, with peaks (corresponding to the impact of the rollers) approaching 9 bar, or twice the pressure exerted by the tyres.
“The study concluded that the caterpillar tread’s uneven load distribution and the extra pressure on the ground, compared to the IF tyres, did not give it an advantage in terms of soil compaction,” Lawton added.
Michelin says the key to achieving this performance is its patented Ultraflex technology; it says the CerexBib is the only commercially available harvester tyre that can work at a pressure of less than 2 bar. This is around 30 per cent less than conventional tyres.
The IRSTEA is backed by an annual budget of 115 million euros and has 1,750 employees, including 700 engineers and researchers and 250 doctoral students, who work in 19 research units spread across nine sites. The Institute’s goal is to be the European leader in environmental research, as well as an important scientific centre to support public policy making.