05.05.2026 – 09:55

Agile special-purpose truck for forestry applications

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Agile special-purpose truck for forestry applications

Electro-hydraulic trailer steering improves manoeuvrability

Key aspects:

WIESE Fahrzeugbau have developed a special-purpose 2-axle roll-off tipper with two forced-steering SAF trailer axles for maximum manoeuvrability on narrow forest tracks.
The forced-steering axles from SAF in combination with the electro-hydraulic VSE Advanced Steering system improves manoeuvrability, reduces tire wear and increases economic efficiency during use.
The vehicle was created in close collaboration between WIESE Fahrzeugbau, SAF-HOLLAND and the Austrian forestry business owner Johannes Suntinger.

Transporting wood chips from the forest is a challenging task for the vehicles used. The material is usually produced directly in the forest and then transported to temporary storage sites for drying. The crucial requirements are a large load capacity and good manoeuvrability to safely navigate on narrow forest tracks and unpaved forest roads.

Based on this, WIESE Fahrzeugbau, together with SAF-HOLLAND, developed a special vehicle solution for forestry applications: a 2-axle roll-off tipper with forced steering and drum brakes on the axles and the electro-hydraulic VSE Advanced Steering system, as well as a specially designed 50-m³ roll-off container.

Unusual axle configuration

The vehicle is equipped with three axles on the truck and two forced-steering SAF axles on the trailer – a relatively rare configuration. While conventional semi-trailers usually have three rigid axles, WIESE is specifically using forced-steering axles to significantly increase manoeuvrability.

The trailer axles are steered with the electro-hydraulic VSE Advanced Steering system. The system continuously analyses the vehicle speed, the steering angle and the direction of travel of the vehicle and adapts the steering movements of the axles in real time.

A crucial advantage: The solution works fully independently and requires no additional connection to the tractor. This means that the system can be flexibly integrated into different trailer concepts.

Precision steering even when reversing

In contrast to passive steering systems – often referred to as the “shopping trolley principle” – the new vehicle uses two SAF axles with true forced-steering. This design enables precise steering of the axles during forward and reverse movement. The hydraulic pump of the system is installed directly on the trailer and is supplied with power from a 24-V connection to the tractor. Optionally, the system can be equipped with maintenance-free batteries that are charged during driving. The control system uses sensors and a programmable software, allowing the steering angle and axle characteristics to be adapted to different vehicle configurations. The system can be combined with axles from different manufacturers and permits axle loads of up to eleven tons per steered axle.

Advantages in forestry applications

The practical benefits of the trailer steering come into play in particular on challenging forest tracks. The active steering of the trailer axles improves the vehicle’s agility significantly and makes it easier to manoeuvre on narrow tracks or in tight storage areas.

Reduced tire wear and lower rolling resistance during cornering are additional advantages. The integrated hook lift offers additional flexibility, enabling fast set-down and pick-up of roll-off containers, even on uneven terrain. This allows the driver to set down a filled container and directly pick up an empty one to reduce downtime.

Field test in an Austrian forestry company

The vehicle was developed in close collaboration between WIESE Fahrzeugbau, SAF-HOLLAND and the Austrian forestry business owner Johannes Suntinger. After around two months of use and about 2,000 kilometres on forest tracks, the bottom line was positive. “Many roads here are extremely narrow and the tight bends are often a real problem,” explains Suntinger. “With the two steering axles, the trailer accurately follows the steering motion of the vehicle. We can get through easily, even on narrow forest tracks.”

Innovative steering axle for forest tracks, construction sites and inner cities

“We see the SAF steering technology in combination with the VSE Advanced Steering as a true innovation for trailer manufacturers and fleet owners alike. The system offers a clear advantage in particular if there is little space for manoeuvring and reversing is part of the standard process – whether on forest tracks, at construction sites or in inner city areas. In addition to this, our customers benefit from a lower vehicle weight and therefore higher economic efficiency,” explains Alexandre Charpiot, Vice-President Sales EMEA at SAF-HOLLAND.

More Information: VSE Advanced Steering

Electro-hydraulic trailer steering for special-purpose vehicles

The VSE Advanced Steering system is an electro-hydraulic trailer steering system for active steering of trailer axles. The solution works independently and requires no mechanical connection to the tractor. Sensors record the driving status and steering angle of the tractor. An electronic control system then computes the steering angles of the trailer axles in real time and implements them through the hydraulic system.

Technical features