Spierings SK377-AT3

The Spierings SK377-AT3 was introduced as one of the most compact models in the Spierings mobile tower crane lineup, specifically targeting projects where access, space, and setup time are critical constraints. Built by Spierings, the SK377-AT3 reflects the company’s long-standing philosophy of delivering true tower crane performance on a fully road-going chassis. Its three-axle carrier keeps overall dimensions and axle loads relatively low, making it particularly suitable for tight urban streets, residential areas, and refurbishment projects where larger mobile tower cranes would be difficult to position.

Mounted on a three-axle all-terrain chassis, the SK377-AT3 offers good maneuverability and straightforward road transport between sites, with a maximum travel speed in the region of 80 km/h. All axles are steered, allowing the crane to negotiate narrow access roads and confined site entrances with ease. This compact mobility is a key reason the SK377-AT3 has been widely adopted for city-center projects where crane relocation is frequent.

The crane is equipped with a lattice jib with a maximum length of around 45 metres. In horizontal trolley jib configuration, the SK377-AT3 can lift up to approximately 2,000 kg at the jib head, while at shorter radii it reaches a maximum lifting capacity of roughly 7,000 kg. These capacities make it well suited for typical urban construction tasks such as handling concrete buckets, formwork, reinforcement cages, and prefabricated building elements. By raising the jib to a steep angle, the crane achieves hook heights of approximately 50 to 55 metres, depending on configuration, enabling efficient work on mid-rise residential and commercial buildings.

A defining feature of the SK377-AT3 is its fast, fully automatic erection system. The crane can be erected by a single operator at the push of a button, following a controlled and compact assembly curve that requires very little space around the crane. This makes it possible to set up the crane in courtyards, narrow streets, or directly adjacent to existing buildings. Once erected, the crane can remain standing between work phases without dismantling, which significantly improves productivity on projects with intermittent lifting needs.

All crane working motions on the SK377-AT3 are electrically driven, including hoisting, slewing, trolley travel, and erection. Electrical power for crane operation is supplied either by an onboard diesel generator or via an external site power connection. When connected to external power, the crane operates quietly and with zero local emissions, an important advantage for noise-sensitive urban areas and projects with strict environmental requirements. The electric drives provide smooth, stepless control, allowing precise load positioning comparable to that of a conventional top-slewing tower crane.

The crane is supported by a four-point hydraulic outrigger system with automatic leveling and electronic inclination monitoring. Different outrigger base widths can be selected to suit site conditions, balancing available space with required lifting capacity. The stable carrier design and favorable center of gravity also allow limited repositioning of the crane on site while erected, in accordance with manufacturer guidelines.

The operator’s cab is designed to tower crane standards, offering good visibility of the load and working area, ergonomic controls, and a comfortable working environment. Integrated monitoring and safety systems provide continuous feedback on crane configuration, load status, and wind conditions, supporting safe and efficient operation.

Overall, the Spierings SK377-AT3 is best described as a highly compact, agile mobile tower crane that delivers reliable lifting performance and fast deployment in restricted urban environments. Its combination of three-axle mobility, electric crane operation, and tower-crane-like handling makes it an effective solution for contractors who need flexibility, speed, and precision on small to medium-sized construction projects.