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Trailer Mount Knuckleboom Loaders(Non Current)

A benchmark for the industry, Caterpillar knuckleboom loaders set new standards in performance, controllability and safety.

559 Knuckleboom Loader

Cat® trailer-mount knuckleboom loaders feature hydraulic systems that provides smooth performance and fuel efficiency. High swing torque, swing speed and lift capacity reduce cycle times and lower cost per ton. The heavy-duty booms and structures provide reliable operation and reduce service costs. Spacious work stations, excellent visibility, and ergonomic controls reduce operator fatigue, resulting in a more productive shift. A wide range of machine sizes with optional factory installed hydraulic packages are available to increase loader utilization. Options include bar slasher, circle saw slasher, delimber, carrier and grapple saw.

Product Details


Gross Power 129.9 kW
Cat® Diesel Engines C6.6 Tier 3
Engine RPM (Rated) 2200 RPM

Operating Specifications

Knuckleboom Length 9.8 m
Stabilizers (4) - Pad Size 55.8 cm × 71 cm (22 in × 28 in)
Swing Bearing - Diameter - OD 129.5 cm


Operating Weight 14605 kg
Counterweight 635 kg
Operating Weight* 14605 kg

Hydraulic System

Flows @ Rated Speed 416 L/min
Swing Speed 11 RPM
System Pressure 24131 kPa

Service Refill Capacities

Fuel 379 L
Hydraulic 302.8 L

Operator Station

Unprecedented visibility and comfort

The operator station is designed with comfort in mind. The spacious cab features a large, fully adjustable suspension seat with lumbar support. Fold-up armrests are fully adjustable to allow adjustment of the joystick controls to match the operator for ease of operation and increased performance.Excellent visibility of the work area is provided through large tinted cab windows. Overhead visibility is maximized through the large, tinted Lexan skylight. Operator protection is afforded through the front guard. This swing-out guard is designed for quick and simple access to allow cleaning of the front window.

Hydraulic Packages

Factory installed hydraulic packages increase job site performance and versatility

Cat knuckleboom loader hydraulic systems are designed to satisfy the productivity demands of loggers. The 559 has an open-center, “Negicon” piston pump hydraulic system at its heart. This hydraulic system provides market leading performance and unmatched reliability which has allowed the 559 to be the market leading knuckleboom loader.The 559 is a high performance Circle Saw Slasher machine. Added to the core hydraulic system is a dedicated, 246 L/min (65 gpm) piston pump to provide flow to the circle saw slasher that produces quick recovery of the saw blade to increase the system productivity.

Complete Customer Care

Service you can count on

Product Support

Cat dealers utilize a worldwide parts network to minimize machine downtime. Plus you can save money with Cat remanufactured components.

Machine Selection

Make detailed comparisons of machines you are considering. What are the job requirements and machine attachments? What production is needed? Your Cat dealer can provide recommendations.


Consider financing options and day-to-day operating costs. Look at dealer services that can be included in the machine’s cost to yield lower owning and operating costs over time.

Customer Support Agreements

Cat dealers offer a variety of customer support agreements and work with you to develop a plan to meet specific needs. These plans can cover the entire machine, including attachments, to help protect your investment.


Improving operating techniques can boost your profits. Your Cat dealer has videos, literature, and other ideas to help you increase productivity. Caterpillar also offers simulators and certified operator training to help maximize the return on your investment.


Repair, rebuild, or replace? Your Cat dealer can help you evaluate the cost involved so you can make the right choice.
    •  Cat® C6.6 129.8 kW (173 hp) Tier 3 Compliant
    •  Electrical
    •  Pump Drive
  • Cat® C6.6 129.8 kW (173 hp) Tier 3 Compliant
    • Electrical
      • Pump Drive
          •  97.8 cm × 142.2 cm (38.5 in × 56 in) Right Side Mounted with Isolation Pads
          •  Tinted Safety Glass Windows, Lexan Skylight, Sun Visor
          •  Fully Adjustable Seat with Fold-up Armrest
          •  Operator Protection Guard
          •  Pressurized Cab with Heat/Air Conditioning
          •  Integral Heat/AC Ductwork
          •  Analog Gauges
          •  Windshield Wiper/Washer
          •  Horn
          •  Defroster Fan
          •  12V Power Point
          •  Dome Light
          •  Fire Extinguisher
          •  Sliding Cab Window
          •  Radio Ready (Speakers, AM/FM Antenna)
          •  Two Variable Displacement Axial Piston Pumps, Pilot Pump
          •  Dedicated Circle Saw Piston Pump – 246 L/min (65 gpm)
          •  Controls
          •  Filtration
          •  Swivel
          •  Serviceability
          •  Auxiliary Hydraulics
        • Two Variable Displacement Axial Piston Pumps, Pilot Pump
          • Dedicated Circle Saw Piston Pump – 246 L/min (65 gpm)
            • Controls
              • Filtration
                • Swivel
                  • Serviceability
                    • Auxiliary Hydraulics
                      • STRUCTURAL
                        •  Grapple Mounting Knuckle
                        •  Lower Frame
                        •  Turntable Mounting
                      • Grapple Mounting Knuckle
                        • Lower Frame
                          • Turntable Mounting
                            • ENGINES AND DRIVE LINE
                              •  Electrical
                            • OPERATORS STATION
                              •  AM/FM/CD Radio/Satellite Radio
                            • STRUCTURAL
                              •  Boom
                              •  Heels
                              •  Grapple Mounting Knuckle
                              •  DS Package with Standard Trailer
                              •  DS Package with Hydraulic Trailer
                            Built for it