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Trailer Mount Knuckleboom Loaders

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

529 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 116.3 kW
Cat® Diesel Engines C6.6 Tier 3
Engine RPM (Rated) 2200.0 RPM

Operating Specifications

Knuckleboom Length 8.8 m
Stabilizers (4) - Pad Size 55.8 cm × 55 cm (22 in × 23 in)
Swing Bearing - Diameter - OD 109.2 cm


Operating Weight 12655.0 kg
Counterweight 1496.8 kg
Operating Weight* 12655.0 kg

Hydraulic System

Flows @ Rated Speed 193, 158, 124 L/min (51, 42, 33 gal/min)
Swing Speed 8.0 RPM
System Pressure 18960.0 kPa

Service Refill Capacities

Fuel 276.3 L
Hydraulic 295.3 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 529 is equipped with a simple open-center hydraulic system with a triple section gear pump supplying the flow. This system is time tested and provides good performance and provides many different types of option packages, such as carrier hydraulics for millyard mobility. The 529 features a unique “flow-on-demand” hydraulic system for the subframe hydraulic components like the stabilizers, slasher or delimber. This system directs flow and pressure to the subframe systems only when required for activating a function. This results in improved hydraulic efficiency, reduced heat and lower overall system horsepower demand when compared to a standard open-center system.

Delimber-Slasher Package

A complete factory installed timber merchandising system

The Delimber/Slasher (DS) package is a complete factory installed timber merchandising system consisting of a knuckleboom loader and grapple, trailer with trailer-mounted delimber and an optional ground saw slasher and is available with all delimbing capable loaders - the 529, 559B, 569 and 579. The structural design on these loaders is proven to provide long life in punishing, pull-through delimbing applications. A three-knife CTR 320 is standard on the package, or a four-knife CTR 426 pull-through delimber is available as an option. These delimbers are designed to allow quick, easy loading of trees and produce clean, delimbed stems in a flash. These delimbers also have central lubrication banks and ground-level oil fill for quick, easy service. An automatic chain tensioner simplifies maintenance and extends bar and chain life. The standard delimbing trailer is built with structural reinforcing in critical areas for durability. This trailer features a roll-up gear for transport and a swing down delimbing foot for operation. The optional delimbing trailer features a hydraulically adjustable landing gear that is adjustable from in cab controls. This feature allows the operator to quickly position the loader in a proper operating position, providing more production capability. Knuckleboom Loader grapples are available in a wide variety of rotator types, jaw sizes and jaw configurations to suit a variety of material handling applications. The CTR 107 Slasher is optional for the DS package. A load-sensing saw feed system delivers smooth, fast cutting cycles. This slasher is available in multiple bunk styles and can be customized for specific log-lengths.

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® C6.6 116.3 kW (156 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)
    •  3 In-line Gear Pumps, Pilot Pump
    •  Swing Motor
    •  Controls
    •  Filtration
    •  Swivel
    •  Serviceability
    •  Auxiliary Hydraulics
    •  Boom
    •  Grapple Mounting Knuckle
    •  Lower Frame
    •  Turntable Mounting
  • Boom
    • Grapple Mounting Knuckle
      • Lower Frame
        • Turntable Mounting
            •  Electrical
            •  AM/FM/CD Radio/Satellite Radio
          • AM/FM/CD Radio/Satellite Radio
            • STRUCTURAL
              •  Heels
              •  DS Package with Standard Trailer
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