The Tallest Boom A Drop-Deck Trailer Can Carry

By Larry Stewart, Executive Editor | September 28, 2010

Arms swing horizontally, extending the footprint to 12 feet 11 inches.
The X-Chassis axles retract for a transport width of 8 feet 1 inch.
The only boom taller than the Z-135/70 is JLG's 150HAX, and the 57,000-pound JLG is 11 feet 6 inches wide with axles retracted. The Z-135/70 - at 44,900 pounds and 8 feet 1 inch wide - is the biggest boom that can be transported on a standard drop-deck trailer.

Genie set out to deliver the greatest access range and capacity that can be transported on a simple drop-deck trailer, and the result is the Z-135/70 articulating-boom aerial platform. It can raise 600 pounds to platform heights of 135 feet. A company press release says, "Genie's Z-135/70 offers the largest working envelope in the articulating boom market, providing a maximum working height of 141 feet, horizontal outreach of 69 feet 9 inches, and up-and-over clearance of 75 feet 6 inches."

With the boom raised to 75 feet, the 44,900-pound machine can reach almost 60 feet horizontally from its centerline. With the boom stowed, the unit is 42 feet 5 inches long and 10 feet 1 inch high. The machine is 8 feet 1 inch wide when its X-Chassis axles are retracted.

Every other big boom on the market, including Genie's machines over 80 feet tall, have telescoping axles. Each of the Z-135/70's wheels and wheel motors is mounted on a cast-steel arm that swings horizontally from a vertical pin on the frame. Hydraulic cylinders fold and unfold these arms to extend the width of the lift's footprint to 12 feet 11 inches. Electronic sensors monitor the arm and wheel positions and manage their proper alignment even when switching from two-front-wheel steering to two-rear-wheel steering to four-wheel or crab steering.

"When we produced the Superboom  the S-125 six or seven years ago, we brought a number of technologies that affect how it operates, how it's serviced, how it is transported," says Brad Allen, product management team leader at Genie. "We used the same control system the ALC 1000 system on the Z-135/70, and the independent steering system with sensors for wheel position.

"We learned a lot in six or seven years, though, and one of the things was that sliding axles caused some people problems," Allen adds. "They've been on booms for 15 years  since booms went over 60 feet and as machines got heavier, they caused maintenance problems. Not safety or reliability issues, but they could be inconvenient to service.

"That's why we introduced the X-Chassis. It has half of the moving parts."

The new jib, called Jib-eXtend, stretches the platform from a stowed length of 12 feet out to 20 feet and swings upward in a 70-degree arc and down 40 degrees. With the boom in the transport position, the jib can be raised to its maximum height without giving up any of the machine's three-mile-per-hour ground speed.

In a very real sense, the Z-135/70 is the result of what Allen calls "the best thing that's happened to Genie"  the purchase of the company by Terex.

"Terex resources have given us the opportunity to mature a little bit in how we approach product development and production," says Allen. "We're more thoroughly testing products, and we're better equipped to consider the breadth of customer applications during the design of a machine."

For the Z-135/70, that translated into the most expensive product-development process in Genie's history. Two prototypes and eight pre-production machines were tested extensively.

"One of the things that has happened since the Terex merger is that we've created the position of director of quality and put in a whole quality-management system," Allen says. "Almost three years after the merger, we have a much more active quality program. Anybody would have expected the exact opposite."

Suggested retail price for the Z-135/70 - with four-wheel drive, four-wheel steer and a 78-hp air-cooled Deutz diesel engine - is $364,000. An 80-hp Cummins or 86-hp Perkins are $2,100 options.

Biggest Articulating Booms
Make Platform Height Horizontal Outreach Up-and-Over Clearance Capacity (lbs.) Weight (lbs.)
Haulotte HA100JRT 98' 5" 69' 11" 37' 3" 551 45,853
JLG 1250AJP 125' 0" 63' 2" 60' 6" 500 44,000
Genie Z-135/70 135' 0" 69' 9" 75' 6" 600 44,900
JLG 150HAX 150' 0" 79' 3" 80' 0" 500 57,000