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These three tractors were used by Ohio State University to conduct a study analyzing the impact track widths and inflation pressures have on compaction. The same radial tires, set at different inflation pressures (top photo), performed both first and last. The 35" tracks (middle photo) came in second, while the 25" track placed third Researchers at Ohio State University (OSU) and the University of California-Davis have identified the most valuable tool available in the fight to reduce the yield-robbing effects of compacted soils.
It's a tire pressure gauge. In the Ohio State study, a properly balanced and ballasted Deere 8870 four-wheel-drive tractor equipped with 710/70R38 radial tires produced the least amount of compaction. The Deere 8870 set up with correct tire inflation pressures of 7 psi front and 6 psi rear finished ahead of a Caterpillar Challenger 75 with 35" belts, and a Challenger 65 with 25" belts.
To underscore the dramatic influence proper inflation pressures have on compaction, the Deere 8870 was also tested with all eight tires at 24 psi. At those pressures, the Deere 8870 finished last rather than first. The only variable was tire inflation pressure.
"The new load/inflation pressure tables for radial tires were issued in 1992 by the tire companies," says Jack Wiley, Deere principal engineer at the company's Technical Center in Moline, Ill. "But they have not been widely applied by farmers. The reason is that farmers intuitively believe that a tire with large 'cheeks' is either underinflated or overloaded. The Ohio tests prove that when you overinflate radial tires you shrink the footprint and increase compaction."
In fact, overinflation affects much more than soil compaction. At the University of California-Davis, researchers tested Deere's 8870 with radial tires inflated to 24 psi, then compared the results with the same tires inflated to the new correct low-pressure guidelines.
In field operations, the correct lowpressure inflation level reduced fuel consumption up to 20%. The lower pressures also allowed the Deere 8870 to work more efficiently. While disking, the tractor with lower tire pressures covered almost an extra acre every hour. The reason: Properly inflated radial tires have large footprints that significantly increase traction.
The bottom line is that tractor performance-as it relates to soil compaction, fuel use and work...