Convincing DLG test results for traction, output and fuel consumption underpin performance claims for a new range of tractor tyres from Nokian.

The Soil King VF design marks the Finnish manufacturer’s first foray into the most sophisticated traction tyre category, which requires designs to combine considerable sidewall flexibility with high load-carrying capacity.

See also: High-flexion tractor tyres – how they work and what they cost

The consequent ability to run at lower inflation pressures than a “standard” tyre for a given load results in a larger footprint and reduced surface ground pressure – or the ability to cope with heavier loads at regular pressures.

Nokian’s new contender in the VF (Very High Flexion) category achieves this with its so-called Flexforce technology, while adding a distinct tread design.

This has lugs of a conventional shape for about three-quarters of their length out to the sidewall, but they alter at their inner end into a broader, blocky shape to form a near-continuous centre line around the tyre.

The aim, say Nokian engineers, was to achieve a lug shape and carcass structure that give a good “bite” into the soil surface for cultivations and other draft work, along with good traction, low rolling resistance, and comfortable levels of noise and vibration on the road.

Test results

That goal has been achieved, certainly as far as tractive performance and efficiency is concerned, judging by the results of a DLG comparison of the new design with three other premium tyres of the same 600/70 R30 front, and 710/70 R42 rear size pairing.

For example, despite having a tread pattern that might be considered a trade-off between on-road and in-field performance, the Soil King VF achieved the lowest wheelslip on short stubbles at 7.5%, versus 9.2% and 10.2% for the other two VF tyres in the comparison, and 11.2% for a slightly stiffer IF-spec design.

That translated into a more than 6% output advantage over its best-performing competitor at 4.23ha/hour in the 7kph simulated cultivations test, and with the added attraction of 7% lower specific fuel consumption.

On the road, fuel use was also the lowest of the group – whether running at 50 or 60kph – and the tyre recorded the least wheelslip during the uphill towing element.

DLG testers noted that a factor in the Soil King VF’s performance advantages could be an observed lesser tendency for the lugs – which appear to be well-reinforced at their root – to deform when the tyre is rolling on tarmac and operating under load.

The new range is now available from UK distributor Nordic Tyres in an initial eight sizes for 28in, 30in, 34in, 38in and 42in rims in nominal widths up to 710, including as an OEM option on Fendt 728 Gen7 and Valtra Q and S series tractors.