1. Belt width comparison on tilled soil (belted tractor total weight = 12700 kg; wheel tractor axle weight = 8303 kg).

2. Belt width comparison on subsoiled land (belted tractor total weight = 12700 kg; wheel tractor axle weight = 8303 kg).

3. Belt manufacturer comparison on firm untilled soil (belted tractor total weight = 12700 kg; wheel tractor axle weight = 8303 kg).

5. Belt manufacturer comparison on tilled soil (belted tractor total weight = 12700 kg; wheel tractor axle weight = 8303 kg).

6. Belt manufacturer comparison in subsoiled tractive condition (belted tractor total weight = 12700 kg; wheel tractor axle weight = 8303 kg).

7. Performance of 630 mm (25 in.) belt on three surfaces (belted tractor total weight = 12700 kg; wheel tractor axle weight = 8303 kg).

8. Performance of 20.8R42 dual tires on three surfaces (axle load = 8300 kg; tire pressure = 83 kPa).

9. Soil, Tire, and Traction Equations

12. Wheel Section

14. Tractor Performance

16. Power delivery efficiency (PDE) is defined as the ratio of the delivered drawbar power of a tractor to the vehicle input power of the tractor. It represents the percentage of power produced by the engine that is available as tractive power delivered through the drawbar

18. Power delivery efficiency depends on the performance of the PTO and transmission drivetrains as well as the performance of the tires or other traction device. Various power losses can be summarized as: PTO power = Engine power - PTO drivetrain loss - Hydraulic loss from PTO operation. Axle power = Engine power - Transmission drivetrain loss - Hydraulic loss from transmission operation. Drawbar power = Axle power Χ tractive efficiency.

20. Belted and tire vehicle power delivery performance in primary tillage using PTO power calculated from engine power.

21. Belt and wheel tractive performance in primary tillage.

22. Approximate agricultural tractor power relationships (drivetrain).

24. Tractor diagram for tractor performance prediction spreadsheet (performance calculation).

25. Approximate agricultural tractor power relationships (drawbar).

26. Optimum gross traction ratio (Brixius equation revised for radial-ply tires).

27. Weight-speed-power relationship.

29. Optimum tractor weight and sensitivity analysis (John Deere 8870 4WD).