Mobile Towers Debut

Just a month and a half after Liebherr began offering its MK series of mobile tower cranes in North America, the first one has gone to work.

As noted in Crane Hot Line (June 2024, p. 33), the MK concept puts a self-erecting tower crane on a chassis similar to that used on an all-terrain crane.

The result is a rig that combines the fast setup and long reach of a self-erecting tower crane with the easy roadability of a mobile crane — a tower crane that can do several jobs a day like a taxi crane.

Ideal Crane Rental Inc., Madison, Wisconsin, has taken delivery of one of each of the three MK models Liebherr offers in North America.

The smallest is the three-axle MK 73-3.1. It can lift up to 13,227 pounds, and can pick 4,409 pounds at its 126-foot maximum radius.

The midsized model is the four-axle MK 88-4.1, which has a maximum capacity of 17,636 pounds and can lift 4,850 pounds at its 147-foot maximum radius.

The largest model is the five-axle MK 140-5.1, which can lift up to 17,636 pounds or pick 4,188 pounds at its 213-foot maximum radius.

The jibs on all three models can be luffed to 0, 15, 30 or 45 degrees, and the MK 140-5.1’s jib can additionally be luffed to 70 degrees for a whopping 312 feet of hook height with 2,800-pound capacity.

So far, the MK 88 has been on several jobsites, and Ideal has work lined up for the other two models, which it expects to put into operation soon.

“Customers are really excited about the mobile tower crane concept and are looking forward to the benefits all three of these models can deliver,” said Kristin Chose, Ideal Crane’s director of business.

Built for Mobility

Robert Kalhagen, president of Ideal Crane, said “These mobile tower cranes will save our customers time and money because they can often arrive complete, then be set up and making lifts in about 20 minutes. The setup and operation can all be done by one person.”

Kalhagen founded Ideal Crane Rental in 1973 and has operated cranes for more than 45 years.

He said that with full counterweight, the MK 88 weighs about 112,000 pounds, or 28,000 pounds per axle. “In Wisconsin, it can travel at that weight on a single-trip permit that costs a little over $100,” he said. “Removing counterweight can reduce the axle loads to as little as 22,000 pounds, but sending a support truck would cost a lot more than $100, and installing the counterweights on a jobsite would lengthen setup time.”

Kalhagen expects the MK 88 will average one to three jobs per day, depending on the types of work and locations.

He anticipates that the smaller MK 73 will also average about that many jobs per day. “The MK 73 is the right size for a wide range of taxi-crane work, from setting smaller air units to trusses and industrial roofing,” he said. “It is ideal for doing quick jobs and then moving on.”

Kalhagen expects the larger MK 140 to be popular for jobs that need heavier lifts or longer reach, for example setting steel, doing bridge work and placing cell-tower equipment.

Performance Edge

Kalhagen said that the work the MK 88 will do has traditionally been handled by 100-ton rough or all-terrain cranes.

He notes that a mobile self-erecting tower crane offers several advantages over those kinds of cranes.

“First, the mobile tower crane can arrive complete and be run by just one person,” Kalhagen said. “Second, once the operator has set the outriggers, he or she can erect the crane in 11 minutes by holding one lever. Third, the crane runs quietly, either on 480V plug-in power or on a small diesel generator that’s built into the crane. And fourth, the operator can run the crane with wireless remote control or from a comfortable cab that can be moved to any height on the tower that gives the best view.”

Dustin Resch has operated cranes at Ideal for a decade.

Resch now oversees Ideal’s 19 Liebherr K-Series fast-erecting tower cranes and is in charge of Ideal’s three new MK mobile tower cranes.

“All three of our new MK mobile tower cranes are really well thought out and have a lot of features that make them both efficient and easy to operate,” said Resch.

“The outriggers are hydraulic, the crane self erects in 11 minutes with one lever and the crane controls are smooth and easy to operate,” he said. “Even luffing the jib takes just the push of a button. There are just so many features that make life easy for the operator and enable productivity.”

Resch’s favorite feature may be the comfortable cab that can be raised to any height to give the best view of the load and jobsite.

“The elevating cab is such an advantage for the operator,” said Resch. “On the MK 88, it can go as high as 99 feet, so you can see across the top of a nine-story building.”

He added that the crane’s camera system also boosts accuracy, productivity and safety.

“The camera on the trolley looks directly down at the load and what’s below it,” he said. “At an industrial jobsite, the camera helped me set seven HVAC units precisely onto roof-mounted supports.”

Kalhagen said, “Our MK mobile tower cranes do jobs that once took a larger crane with multiple counterweights and jibs. The efficiency and productivity of these mobile towers helps our customers make the lifts they need while reducing costs.”

Ideal Crane Rental plans to send its MK mobile tower cranes to serve customers throughout Wisconsin.

The company now has offices in  Madison, Milwaukee, Green Bay, La Crosse, Oshkosh and Tomahawk, and will soon open an office in Stevens Point.