The Nokian Forest King 2 has been designed for specialised use with tracks.The Forest King 2 has been designed to work well with tracks. It provides track protection at every point, and keeps the track links straight on the surface of the tyre. The grip between the tyre and track has been improved by increasing the straight section of the ribs and grooves of the centre part. The shape of the tyre shoulder and the new tread pattern improve support for the tracks and help them stay on.
The high-grip pattern means that the tyre does not need to be tensed, which reduces the stress on the tyres and journal boxes. Puncture protection is improved by increasing the material strength on the tyre shoulders. A new tyres size has also been introduced, being the 780/50-28.5 PR 24. The rim diameter has been increased to 28.5 inches to match the increased pulling power of machines and to prevent the tyre spinning on the rim. The larger tyre diameter also allows for a higher load bearing capacity at similar inflations. It also improves traction and the off-road capabilities of the machine. The new tyre size is suitable for heavy forest machines weighing over 20 tonnes. Source: http://www.nokianheavytyres.us/news-item?id=32398776