Self-propelled sprayers are still an important segment of the machinery market and they will require tyres specifically designed for their use.
The biggest problem caused by the thin wheels needed to fit down tramlines is the excessive ground pressure they cause; modern machines may be carrying 10t of water and 50m booms.
High pressure increases soil damage
Up until now, row crop tyres have required high inflation pressures to maintain their shape and prevent tyre wall damage during cyclic fieldwork operations (CFO), which includes both field and road work.
Michelin has taken a notable step forward with the introduction of its revamped SprayBib tyre range which has a new carcase design and a new tyre size.
The company claims increased load capacities of up to 14% at cyclic field operations with allowable speeds up to 30km/h.
The reinforced casing design allows added axle loads of up to 1.3t and non CFO road speeds of up to 70km/h, although these parameters are dependent on the particular tyre in use.
Low pressure and extra traction
What is of great interest to farmers is that the updated range has been developed to work in the field at much lower pressures than the current items, and yet still provides a 20% increase in traction.
Due to this new casing design, which is formulated to VF (very high flexion) and CFO standards, the operating pressures may be reduced to 0.7 bar (10psi) for cyclic use, and so greatly ease soil compaction.
For smaller sprayers, Michelin SprayBib CFO can operate at pressures as low as 0.8 bar (12psi), whereas the first generation Michelin SprayBib starts at a minimum of 1.8 (26psi) bar, depending on size.
Choice of 12 for self-propelled sprayers
The company suggests that due to the higher than normal number of robust tread lugs, the tyres offer increased longevity over their predecessors.
The new tyre to be introduced will be the VF 420/90 R34 174D/170E – a completely new size in the range and, like the others, vibration levels transmitted to the driver are minimised due to its VF construction.