The improvements include increased traction, a larger bunk size and a refined power train.

The Komatsu 855.1 has a 14 tonne load capacity. To make sure that operators can utilise the full 14 tonnes, Komatsu have increased the bunk size by 10%.

Traction has been increased to 182 kN (20.5 tonf), which is an 11% increase over the previous machine. Changes to the power train have been made to increase the forwarders reliability. The bogie axles now have a reinforced differential, and dual bogie bearings. The transmission of the 855.1 also has lower gearing than before. The new bogie axles have resulted in the rear frames being modified to make them suitable for bogie stops. The new dual bearings on the bogie axles increase the distance between the wheels and the frame by 33 mm (1.3 in) on both sides, which allows more space for bogie tracks. Source: www.komatsuforest.com.