Wheel Slip
The drive wheel slipping without advancing while it turns in the soil, that is, the difference between the circumferential speed of the wheel and the tractor's actual speed. A certain amount of slip is unavoidable in the field and a band of typically 10-15 percent is targeted for efficiency; above this band, loss of fuel and time and soil compaction increase.
Slip occurs when the drawbar force exceeds what the surface in contact with the soil can carry. The practical way to measure it is to count the wheel revolutions over the same distance loaded and unloaded.
- Causes of excessive slip: too much depth, insufficient ballast, low tyre pressure, worn tyres.
- Slip close to zero is also undesirable; it means the tractor is heavier than necessary and compacts the soil.
- When slip increases, the forward speed falls even if the engine speed does not.
Draft control comes in exactly at this point: when the soil hardens it raises the implement slightly, reducing the draft load and therefore the slip. Electronic retrofit kits do not produce this function; if your tractor has no draft control, slip management is done with depth adjustment, ballast and tyre pressure.
The context where this term is used: Converting a tractor hydraulic lever to electronic control