All leading tractor manufacturers offer stepless transmission options, which they have either developed themselves or sourced from outside suppliers. Each transmission has its own unique design that can lead to differences in efficiency. This was found to be true from a comparison of six tractors that had previously been assessed at the DLG test station
What horsepower an engine puts out at the flywheel is not the absolutely critical figure. With tractors, much more important is how much of the engine’s power is actually available at the pto shaft and at the wheels. After all, it’s this power that’s going to determine performance.
Ultimately, it’s about gearbox efficiency and losing as little power as possible from the flywheel to the pto and wheels. The best indicator for powertrain efficiency (engine, transmission and axles, etc.) is specific fuel consumption. This figure reflects exactly how many litres (or grams) of diesel fuel are combusted to generate a specific drawbar power.
The first thing the DLG test engineers measure in a profi tractor test is the tractor’s pto output (power and torque) curve under full load. Torque is measured at 100rpm (engine) stages, and the pto output is calculated at each one of these stages. Analysing the output at each point, the testers can determine at which speed the engine delivers its maximum output.
