EQUIPMENT & TECHNOLOGY

AVOID A SKID STEER

/CTL & Attachment Mismatch

Universal skid steer and compact track loader (CTL) couplers allow you to mate an attachment with any brand of equipment, but they can also allow size mismatches between the carrier unit and attachment. Improper attachment use can lead to accidents, downtime and unnecessary expenses.

Perhaps the most important consideration is the physical size of the attachment and how it sizes up to the capabilities of the loader.

“As far as the attachment fitting to the machine, we always recommend that the customer has an awareness of what the machine capabilities are, as well as the attachment capabilities,” says Mike Fitzgerald, loader product specialist, Bobcat. “On the machine, you have the rated operating capacity. You want to take into account what that attachment might weigh. We have an approved attachment list for each of the different sizes of machines.”

Attachments are carefully vetted. “One thing we evaluate from the attachment side is the different operating positions,” says Travis Kidder, product specialist, Bobcat. “Even if an operator is grabbing an attachment just to move it around and potentially load it onto a trailer, that operator can get into a lot of trouble.”

When lifting an attachment to put it onto a trailer, the center of gravity changes as you get higher and further away from the loader. So, you really need to pay attention to the rated operating capacity versus the weight of the attachment, as well as how far that weight is sitting out from the center of the machine.

“The one thing that we push our sales staff when we’re training [them on] matching attachments with tractors is knowing the rated operating capacity of the machine,” says Ryan Ruhl, team lead for compact construction equipment and training, John Deere. “Some of those attachments are very heavy. [How] to keep the tractor good and stable is a conversation that needs to be had.”

Some attachments may require counterweights. “With our lineup of attachments and our tractors, we make notes when counterweights could be a benefit to the machine,” says Ruhl. “We are being more proactive about training our sales staff on matching not just the flow and horsepower, but also the weight and understanding what rated operating capacity is versus maximum lift weight.”

In some cases, attachments that are too large can result in structural damage to the machine. “If you have a snow blade that’s far too wide for a smaller skid steer, you could catch a curb or rock going across the parking lot and damage the loader arms,” says Kidder.

It is not always the attachment that is too large. “You can definitely get the opposite side, where the carrier is too big for an attachment,” says Kidder. In this case, the attachment may not be able to hold up to the applied downforce or hydraulic horsepower of the carrier.

Flow and Pressure Considerations

In terms of hydraulic system performance compatibility, consider the performance and limitations of

Bobcat

both the carrier and attachment. Each loader can put out a certain maximum flow and pressure, and every attachment is capable of accepting certain flows and pressures. “You want to make sure those are matched,” says Fitzgerald. If you are not certain, the dealer is a good place to start.

Just because you can hook up the attachment doesn’t mean it is compatible. “With the universal nature of the skidsteer-style quick attach, you can pick up a variety of different attachments,” says Jason Simmons, attachments program manager, John Deere. “You can specifically see mismatch occurring on the hydraulic side.”

A prime example is trying to run a high-flow attachment with standard flow. “You are not getting the optimum performance out of the attachments because the carrier isn’t capable of high flow or vice versa—trying to run a machine on high flow with an attachment that’s only capable of standard flow,” Simmons notes. “It can lead to hydraulic failures on the attachment or other issues with the attachment not being able to withstand that flow rating.”

Too much flow from the carrier will put excessive force on the attachment, causing it to wear faster and reducing performance. “With newer machines that are capable of higher pressure...we do see some of those issues today where the system is capable of higher pressure than the attachment is rated for,” says Simmons.

Hydraulic horsepower to run a specific attachment comes down to two key variables. “The flow and pressure is what gives you the hydraulic horsepower,” says Fitzgerald.

For some attachments, you should consider more than hydraulic horsepower requirements. “We’ve seen some situations where the attachment will have a flow spec. Let’s say it can operate between 26 and 41 gpm,” says Ruhl. “If you utilize a 75-hp tractor that produces 32 gpm, it meets the need of that attachment, but overall, it might not have enough horsepower to push through the material. The tractor can operate the attachment within the hydraulic specs, but it doesn’t have enough horsepower [to perform the task].”

The laws of physics dictate that the more power you have available, the more work you can accomplish. According to Case Construction Equipment, one of the most common mistakes that contractors make is buying a skid steer without enough hydraulic power.

The standard-flow auxiliary hydraulics package is the most common system, Case notes. Although flow rates differ by manufacturer and skid steer model, a standardflow system ranges from 17 to 24 gpm. Standard-flow auxiliary hydraulics are included on all skid steers from the factory and operate on the same pressure as the machine’s main hydraulics, which is approximately 3,000 to 3,500 psi. A high-flow auxiliary hydraulics system also operates on the same pressures (roughly 3,000/3,500 psi) as the main hydraulic circuits but offers a flow rate ranging from 30 to 38 gpm.

When even more hydraulic power is required, an enhanced highflow auxiliary hydraulics package is available. According to Case, this highperformance option has flow rates that are similar to a skid steer with a high-flow package, yet operates at up to 4,000 psi. Examples of attachments that require an enhanced high-flow system include larger cold planers, larger mulchers used to clear brush and small trees and large rock saws that you might find in an aggregates operation.

John Deere

John Deere

For some attachments, you should consider more than just hydraulic horsepower requirements. The carrier needs enough engine horsepower to effectively perform the task.