Pottinger has issued an updated guide to tyre choice and use for agricultural implements, including its own balers and forage wagons.

The guide sets out to show the effect of tyre size and inflation pressure on resultant ground pressure and, hence, the extent to which the soil may be damaged.

A company spokesperson explained: “For the sustainable maintenance of soil fertility and the performance of the soil as a natural resource, it is necessary to keep vehicle weight as low as possible and offer the largest-diameter tyres possible for each model.

‘Surface area’

“This enables the load to be distributed as evenly as possible. The larger the surface area of ground contact, the better the retention of the soil structure.”

Pottinger cites the example of a Torro Combiline with an axle load of 10t and fitted with 800/45 R26.5 tyres. This creates a minimum pressure on the road of 1.6 bar and a ground pressure in the field of 1.66kg/cm².

When shod with smaller 710/45 R22.5 tyres, these figures increase to 2.6 bar on the road and 2.2kg/cm² in the field.

Rolling resistance

Drawing on data provided by the Southwest Falia Agricultural College in Soest, Germany, the company also notes that creating a 1cm-deep wheel-mark in the field can consume up to 10% more diesel, due to the increased rolling resistance.

Damage due to compaction can even result in fertiliser costs going up to 20%, or so claims Pottinger.

The manufacturer also notes that the machine and operator can enjoy a smoother ride with optimised tyre dimensions and the right tyre pressure.

However, it goes on to warn that – for safety reasons – tyres should not be over-sized, as this could adversely affect the efficiency of the brakes and handling while cornering.