Extreme maneuverability in tractors: goal achieved?

This could be one of the most popular mantras among agricultural tractor designers, who are increasingly faced with operations that must cope with limited spaces and access to narrow areas filled with obstacles, where machines and implements must “survive” without risking any impact. In particular, working in specialized crops requires highly efficient tractors, capable of delivering excellent performance in terms of steering and agility. The compactness of these machines, characterized by reduced width and length, is a fundamental prerequisite for facilitating passage between rows and operations in confined spaces. A crucial aspect in these contexts is maneuverability, essential to optimize operations among crops, especially when the tractor has to tow bulky implements. For this reason, several technical solutions have been developed to reduce the minimum turning radius, improving efficiency and operational comfort. In recent decades, the increasing power of tractors has also led to an inevitable increase in their size. However, the limits imposed by agricultural viability, such as the width of farm roads or rural paths, have remained unchanged. This has put the brakes on the indiscriminate growth of machines, instead encouraging the development of compact but highly technological tractors, designed to ensure excellent maneuverability without sacrificing performance and productivity.

 

 

This limitation has pushed agricultural vehicle manufacturers to adopt innovative solutions to improve maneuverability, even in more compact models. Improving mobility in tight spaces proves crucial in situations such as maneuvering between vineyard or orchard rows, where a reduced turning radius is essential. Various solutions have been introduced to optimize maneuverability, each with unique features but with the same goal of simplifying operations in restricted spaces.

A technology that is becoming increasingly common involves the advanced positioning of the front axle, which allows for a wider steering angle thanks to the combined movement of wheels and axle. The result? Better management of front implements, more balanced weight distribution, and less need for rear ballast. Another highly effective system is the automatic increase of the peripheral speed of the front wheels beyond a certain steering angle. This allows the tractor to complete the curve more quickly, reducing work time, fuel consumption, and mechanical wear. In addition, it improves traction when exiting rows, especially on wet or sloping terrain.

An example of innovation is represented by systems that allow for very high steering angles, such as those that synchronize the rotation of the front wheels with the axle, permitting an overall steering angle of up to 76°. Other systems, like Bi-speed, work by increasing the rotational speed of the outer wheels, further improving the turning radius. These systems offer a reduction of the turning radius by 18–20% compared to traditional systems. To further optimize maneuverability, many modern agricultural vehicles offer systems that allow adjustment of steering wheel sensitivity according to operating conditions. For example, it is possible to reduce the number of steering wheel turns required to fully steer the front wheels, or to adjust steering resistance to improve vehicle control at higher speeds.

The adoption of four-wheel steering systems, similar to those used in telehandlers, represents one of the most effective innovations in terms of maneuverability.

The rear wheels can:

• steer in counter-phase to the front wheels for tighter turns
• move in “crab mode” to simplify loading and unloading operations
• steer with a delay to maintain the trajectory of towed implements
   

Alternatively, some tractors integrate a hydraulically steered rear axle, combined with a high-angle front axle. This combination ensures excellent maneuverability both in rows and in farmyards.

 

Advanced steering technologies are not limited to tractors alone: they are also found in farm centers, where space optimization is equally crucial.

In self-propelled agricultural machines used for material handling, loading, and unloading, four-wheel steering systems have become increasingly common, if not essential.

Particularly advanced are self-propelled silage-mixer wagons, which today offer up to three selectable steering modes depending on the operation:

• Front-wheel steering for road travel
• Four-wheel steering to drastically reduce the turning radius
• Crab mode, ideal for optimizing lateral maneuverability and reducing soil compaction
   

These solutions are designed for those who work daily in dynamic and complex environments, where even a single maneuver can make the difference in terms of time, safety, and efficiency.