Calibrating the forward speed of a tractor is often overlooked. However, it is a very simple calibration to do and is important to have correct when spraying and spreading fertiliser or slurry.
The simple calibration was described by Ger Griffin at the Precise Application of Fertilisers event held by the Fertilizer Association of Ireland in Teagasc Oak Park recently. Ger pointed out the importance of using the hand throttle to keep speed consistent when spraying or spreading fertiliser.
It is important that the forward speed is correct and consistent. The speed on the clock of the tractor is often measured from the output of the gearbox, according to Griffin. But that’s based on tyres at a certain inflation, which aren’t worn or slipping.
Checking the forward speed and making sure it’s consistent is important.
- Mark out 100m;
- Pick the gear;
- Set the RPM on the hand throttle;
- Take a rolling start;
- Time how long it takes to cover 100m;
- Divide 100m by the seconds it took to travel 100m.
- Multiply by 3.6 to get kph (kilometers per hour).
For example, if it takes 60 seconds to travel 100m the forward speed of the tractor is 6kph.