Details of Liebherr’s new MK 73-3.1

Liebherr's MK 73-3.1 mobile folding construction crane in yellow negotiating a narrow city street Liebherr’s MK 73-3.1 mobile folding construction crane launched on 30 March 2021

Details have been revealed of Liebherr’s new three axle mobile folding construction crane (announced here) launched on 30 March 2021.

The new 6 tonne capacity MK 73-3.1 with lattice tower and folding lattice boom joins the existing, larger, 8 tonne four axle MK 88-4.1 and five axle MK 140 models in the range. It is designed to meet demand for a small, compact and agile mobile construction crane that is fast and flexible in operation, Liebherr said.

Like many wheeled mobile cranes of this size the new MK 73-3.1 is also designed as a taxi crane, to complete several jobs on multiple sites in one day. To this end it is designed for operation by one person and can be set up ready to go in about 10 minutes, the manufacturer said. It is self contained so no support vehicles are needed.


Maximum horizontal reach is 38.5 metres. Two tower heights shown in the specifications give hook heights of 15.3 and 26.5 metres with the jib horizontal. Capacity at jib end is 2 tonnes.

Hook height with the jib fully luffed to 45 degrees is 51 metres and the radius is 26.7 metres. The jib can also be luffed to 15 and 30 degrees. Capacity at the end of the luffed jib is 1,850 kg.

As with other MK cranes, when on site the new MK 73-3.1 can be operated using mains electricity. It will run from a 63 or 32 amp supply, with no reduction in working speed, the company said. Where suitable site power is unavailable an onboard integrated generator can be deployed.

Power and options

It is a one engine design familiar from other Liebherr wheeled mobile cranes and also has the ECOmode to help ensure economical use of fuel. For road travel the crane’s overall length, including front and rear overhangs, is 13.81 metres. It is 2.75 metres wide and 4.0 metres tall.

The elevating operator cabin can be set at any height to offer the best view of the job. It also has the Micromove function for fine positioning. Cameras onboard give the operator a view of both the load and the undercarriage. For manoeuvring in confined spaces there is rear axle steering and five steering programmes. Outriggers can be set asymmetrically.

An option is the Load Plus load curve and reinforced trolley drive mechanism to give as much as 50 per cent more capacity with the jib luffed to the full 45 degrees.

In 1961 Liebherr’s KA series was the first time it had mounted a fast erecting lattice tower crane on a truck chassis. The MK series was launched in 1997. The MK 40 and MK 45 were mounted on conventional truck chassis-cab units.

A Liebherr video of the new crane can be seen here.


Receive the information you need when you need it through our world-leading magazines, newsletters and daily briefings.

Sign up