There continues to be some confusion around the subject of tyre pressures. It is important to understand how to calculate correct tyre pressures to ensure optimal performance of tractor and machine tyres.

To determine correct pressure, the following two elements need to be considered:

  • Total weight on axle when machine is full (eg, when tanker is fully loaded with slurry). This is achieved by reversing a loaded tanker only onto a weighbridge where it is still attached to the tractor but the tractor or drawbar weight is not considered.
  • Speed being travelled at, bearing in mind that road and field speeds will vary.
  • Only when these two factors are considered can the correct tyre pressure be determined.

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    Agrigear has advised that a 20% allowance needs to be considered for road camber. This is because uneven roads can cause loads to move from their central point and lean to one side.

    This is particularly noticeable on the machine side that is closest to the ditch. It will cause an extra loading weight on the left-hand tyres of a machine.

    Following our recent slurry focus feature, Agrigear would like to clarify that the psi figure of 20psi (1.2 bar) stated was incorrect. It recommends that the correct figure should be 24psi (1.6 bar) for a 2,000-gallon (9,000-litre) tanker. In the case of a 3,000-gallon (13,500-litre) tanker, the psi should be 50psi (3.6 bar).