Rough-terrain cranes are big investments, but they can last a long time, so correct use and proper maintenance can help keep a manager’s costs down long-term. It’s also important to know when to employ a rough-terrain crane as opposed to a crawler crane, or even a large telehandler.
These versatile, rubber-tired units often have long lives, lasting 15 to a somewhat surprising 30 years, in some cases. “It depends a lot on the level of use and maintenance,” says Jay Barth, product marketing manager at Terex. “We have reports of some of our legacy brand, Rough Terrain, being over 30 years old and still working.”
Level of use is relative for these workhorses. Some are brought into sites just to pick and carry loads for a day. Others are around for the duration of large jobs, such as in petrochemical construction, where they handle a large number of relatively light lifts all over the site, including setting pipes and pipe racks, according to Barth. They are also used as auxiliary cranes to assemble other cranes.
There are also petrochemical turnarounds. “In a turnaround, multiple cranes are placed in designated sites with designated lifts, minimizing the time needed for the turnaround,” Barth says. “In mining, they’re used for maintenance of heavy mining equipment and other lifting needs, and in construction, typical applications include placing pre-cast concrete or steel sections.”
In some cases there are choices, and a decision has to be made as to what type of lifting machine to employ. But there are definite demarcation lines between rough-terrain cranes, crawler cranes, and large telehandlers.
“The rough-terrain crane is a smaller machine, it’s a little more portable, it’s all rubber-tired, and there’s not a lot of set-up work compared to a crawler crane,” says Jeff Dreger, director of product and customer support for cranes, Sany America. “You can get in and out of a job site, and just drive it off a trailer to have it ready to use in a matter of minutes.”
Telehandlers, while highly mobile, have limits. Barth’s company makes both rough-terrains and telehanders. “The line is quite clear,” he says. “Telehandlers are basically used to unload and place loads within a job site, they have virtually no slewing capabilities and their capacities are very limited. Even the smallest rough-terrain, our RT 230, has significantly more reach and capacity than our largest telehandler, the GTH 1544: 147 feet versus 27 feet, and 30 tons versus 7 tons.”
Trend toward larger sizes
“The market last year was slightly less than 2012 in terms of number of units,” Barth says. “But there was a higher volume in the over 70-ton segment.”
Dreger also thinks the market seems to be leaning to larger machines with more lifting capacity. “When we first started out with the rough-terrain cranes in 2011, it seemed like we were selling more of the smaller-sized machines, in the 60- and 70-ton range, and now we’re seeing there’s more of a trend toward larger machines, 85- and 90-ton, and even bigger than that,” he says.
One reason might be the versatility of larger units. “You can lift smaller loads and still go all the way up to the bigger loads, and you don’t have to bring in a crawler crane if you’re lifting something that’s 90 to 100 tons,” Dreger says.
The ability to do two types of jobs with one unit can be music to the ears of a manager. But when thinking about size, there’s also the issue of transportation.
“The main things customers like are ease of operation and easy job site set-up,” Dreger says. “Once you start getting up to the 80-ton machine, then you have to drop off the counterweights just so you can transport it legally. We ship that machine in two loads; one load for the main machine, and the counterweights on another load. But a plus is that you don’t need another crane to put it together—it puts itself together.”
Many rough-terrain cranes come into a job site on a truck, make quick lifts and leave. “A couple of picks, then it’s gone,” Dreger says. “This makes the rough-terrain crane a popular rental machine, because the contractor can bring it in and take it out pretty quick.”
Rental is a major channel for rough-terrains. “Of all crane types, rough terrains are the most prone to be ‘bare rented,’ meaning just the crane is being rented, without an operator,” Barth says. “And rental companies tend to have a very large stock destined for bare rental. On the other hand, multiple construction companies also have large stocks, especially those connected to petrochemicals.”
There does seem to be in increase in buying over renting since the recession ended, Dreger says, a trend worth watching.
Of the latest technology upgrades to rough-terrains, most have occurred in the cab.
“We’re putting more electronics on the machines, with the load moment limiters and cameras, so there are a lot of different things going on the machines to make them safer and more user friendly,” Dreger says. “That technology keeps advancing as the years go by; anybody can pretty much sit down in the cab and go through the screens and figure out what to do on the machine.” This is likely another reason rough-terrains are popular bare rentals.
“But the base machine isn’t really changing too much, other than going to the new Tier 4 engine requirements,” Dreger says.
There is one very fresh development on base machines that isn’t high technology, at least of the electronic variety. At Conexpo, Manitowoc Cranes showed a Grove RT770E with KZ100 synthetic hoist rope—a rope designed specifically for mobile cranes. It’s a joint development between synthetic rope manufacturer Samson, and Manitowoc.
The two companies conducted several thousand hours of lab testing, and a field trial program, to learn the hoist rope’s performance and longevity characteristics. They used 24,500 feet of rope over the course of 14,000 cycles of reliability testing. Two independent companies tested the rope, as well.
Manitowoc says KZ100 rope is corrosion resistant, requires no lubrication, and reduces wear on drums and sheaves. It’s 80 percent lighter than wire rope and has a torque neutral construction said to eliminate load spin and cabling. The new material also makes for easy handling, reeving, and installation as it reduces kinking, bird caging and damage from other types of cable-spooling issues, according to the company.
“We’re launching the RT770E into probably the most popular capacity class, so we had to distinguish it from the competition,” says Paul Cutchall, rough-terrain product manager for Manitowoc. “We were able to lengthen the boom without adding more size and weight to the chassis. The combination of the RT770E and the KZ100 hoist rope is going to generate plenty of interest.”
The rope, sold exclusively through Manitowoc, will be available as an option on all Grove rough-terrain cranes late this year.
Operating costs and buying advice
Dreger reminds managers that there’s another low-tech way to help keep machines up and running, and operating costs down. “I would think that staying within the guidelines of your scheduled maintenance would be the top thing to keep the overall expense of the machine down,” Dreger says. “Like certain greasing that has to be done on a boom. Check the wire rope, and the fluids and stuff in your drums. Keep proper air pressure in tires. Make sure fluids are up to spec, and that you’re changing them when you should.”
Terex’s Barth urges managers to buy with an eye on total cost of ownership. “This means one has to take into account multiple factors,” he says. “Safety is paramount, and cost here can and should not be quantified—don’t spare in this area if better alternatives are available. Also, how efficient is the machine to transport? How easy is it to maintain and how often do you have to perform maintenance?”
Barth also stresses that managers should take into account all aspects of usage, and not just capacity. That would encompass overall application, how it gets transported to the site, and the transportation cost.