First delivery of largest agri tyre

Measuring 2.32 metres in diameter – that’s 7 feet and 7 inches for those of you reading this in imperial – the new 850/75R42 Firestone DT23 is the world’s largest agricultural tyre. The first delivery of this giant was recently made to a farm in Denmark.

Kristian Kappel of the family-run Brunshøjgaard farm in Thy, Denmark first saw the tyre at a local agricultural show in June 2013, and decided to acquire a set for the farm’s Steiger 450 tractor. The tyres, together with customised rims, have not been delivered and installed in time for harvest.

Manufactured by Firestone in the USA, the DT23 is designed to get the most out of the new generation of heavy tractors with an output of more than 500 hp. Kappel chose to install the tyre on the strength of its improved grip, minimal soil compaction and reduced fuel consumption: “We chose these tyres to get better traction for our Steiger 450,” he explains. “In the past, the tractor had difficulty standing firm. One solution was to install dual wheels on the tractor but since we have so many narrow roads, that does not work for us. With the Firestone DT23, however, we have a much larger footprint in a single tyre, which means we can transfer more power to the ground than ever before.”

The Firestone DT23’s low inflation pressure and reduced weight also minimise soil compaction and fuel consumption, thereby improving crop yields while cutting the costs of working them: “When fitting the new tyres, we were able to remove about 1.3 tonnes of weight from the old rims. That, combined with the lower inflation pressure of 0.8 bar, means a lot in the first 30 to 40 centimetres, which is of great importance deeper down in the soil,” Kappel continued.

The trend towards larger farms and larger, more powerful machinery, places huge demands on tyres to keep pace with the new technology. Employing Firestone’s new AD or “Advanced Deflection Design” technology, the DT23 offers a much larger footprint and higher load capacity than standard radial tyres.

The DT23 has an 850/75 section/aspect ratio and rim size of 42 inches (107 cm). It weighs 510 kilogrammes and has a load capacity of 9.5 tons at speeds of up to 50 kph or 31 mph.