New sizes added to the Alliance Agri Star II and Continental VF TractorMaster tyre ranges cater for heavier, higher-power tractors.

Continental’s newcomer is a high-spec VF category tyre – and the VF 900/60 R42 is the largest size of any tyre produced by the manufacturer.

It joins the five additional 60-, 65- and 75-series sizes in the VF TractorMaster line-up introduced in 2022, and three existing 42in sizes – 650/65 R42, 710/60 R42 and 710/70 R42.

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

Standing 2.1m tall, the newest model caters for tractors of more than 300hp and has the capability to run the same low inflation pressure for both field and road work.

This is thanks to a tough but highly flexible sidewall structure that meets the requirements of the very high-flexion (VF) performance category.

The 189 D load/speed index indicates a maximum carrying capacity of 8,750kg at a maximum sustained speed of 65kph, with increased capacity at lower speeds or the option to operate with lower inflation pressures.

As with all VF tyres, the new-size VF TractorMaster can operate at 40% lower pressure for a given load than a standard tyre, or carry a 40% greater load at the same pressure.

Alliance

The already comprehensive Alliance Agri Star II range gains an 800/70 R38 rear fitment and a 210/95 R18 front axle size, joining 12 additional variations introduced a year ago.

They slot into a line-up of 85-, 70- and 65-series sizes rated at 65kph for extended use on the road, but with a standard carcass structure said to provide an attractive balance of performance, durability and price.

Additional sizes extend the Alliance Agri Star II ‘standard’ tyre range from Yokohama Off-Highway © Alliance

At 1.2bar inflation pressure, the 800/70 R38 has a maximum recommended load of 5,300kg when the highest speed rating is being exploited, or 4,125kg if the minimum 0.8bar pressure for reduced impact in the field is being used.

These figures can be increased by 5% if the tractor’s speed is limited to 50kph on the road and by 9.5% at 40kph.

The lug design is a distinctive feature of the tyre’s tread; a “ledge” halfway down and across the outer half of each lug increases the contact area slightly with a view to enhancing traction.

The larger surface area exposed as the lug wears is said to prolong its service life, especially when a lot of road travel is involved.