Spray application manual
31 January 2025
Module 15: Weight, balance and tyres
15.7 Summary
Published 24 January 2025 | Last updated 20 January 2025
To help with reducing wheel track issues in the paddock and improving boom stability, the spray operator should be aiming to use tyres that have the highest load rating, and also consider using VF or IF tyre types.
The tyre pressure needs to be as low as possible in the paddock e.g. 1.4 to 1.7 bar (20 to 25 psi). Being able to monitor this from the cab can be a great advantage to the operator.
Using IF and VF type tyres (or equivalent) that can handle the same weight at 20 to 40 per cent lower tyre pressures will improve the tyres ‘footprint’, improve sprayer handling and auto-steer functioning, and will help minimise the impact on the wheel tracks.
Tyre tip - aligning tyre centres to improve auto steer function
2 March 2017Tyre tip - aligning tyre centres to improve auto steer function. Another video from GRDC's Spray Application GROWNOTES™ series.
Graham Betts: I know this is a header tyre, but it relates exactly the same to a sprayer tyre.
The tyre information is a VF 620/70 R26. The VF stands for ""very flexion."" What that means is you can carry forty percent greater load at the same tyre pressure, or at an increased tyre pressure, you can actually carry more load.
The 620, once again, is the width of the tread. The 70 is the aspect, meaning seventy percent of 620 is the depth of the tyre. The R stands for radial, and the 26 obviously refers to the rim size.
Another little tip: with our auto-steer now being as precise as 2-centimetre accuracy, it’s a good idea to line up the centre of the tyres rather than the outside. You might have, say, 800s on the front and 620s on the back. In the past, we lined up the outside, which worked fine, but with auto-steer being so accurate now, we really need to be lining up the centre.