Gross Power173 HP (129.3 kW)
Engine ModelCat C4.4 ACERT
Gross Power - 1,800 rpm173 HP (129.3 kW)
Operating Weight33800 lb (15331 kg)
For years, Cat® knuckleboom loaders have been known for superior hydraulic performance in tough logging applications, heavy-duty boom and structures that are built to last, and fuel efficient engines that provide impressive torque characteristics. A complete factory installed delimber slasher (DS) package ensures you have the right grapple, delimber, and trailer combination for any job.


Gross Power173 HP (129.3 kW)
Engine ModelCat C4.4 ACERT
Gross Power - 1,800 rpm173 HP (129.3 kW)
Operating Weight33800 lb (15331 kg)
Operating Weight - Without Grapple33800 lb (15331 kg)
Knuckleboom Length32 ft (9.8 m)
Swing Speed11 r/min (11 r/min)
Tail Swing106 in (2692 mm)
Swing Bearing - Diameter - Ball Path43.5 in (1105 mm)
Swing Torque*49173 ft·lbf (66870 N·m)
Maximum Reach - Standard Boom32 ft (9.8 m)
Hydraulic Tank80 gal (US) (302 l)
Fuel Tank100 gal (US) (378 l)
Engine Oil2.1 gal (US) (8 l)
Swing Drive1 gal (US) (4 l)
Cooling System7.5 gal (US) (29 l)
Hydraulic Pressure - Swing3625 psi (24994 kPa)
Cylinders - Mainone
Hydraulic Pressure - System3625 psi (24994 kPa)
Cylinders - Stabilizersfour
Hydraulic Oil Flow at 1,800 rpm230/174 L/min (60/46 gal/min)
Cylinders - Stickone
Stabilizer Reach Below Grade17 in (433 mm)
Stabilizer Spread - Maximum Down Reach166.8 in (4237 mm)
Stabilizer Pad Size508 × 711 mm (20 × 28 in)
Height - Top of Cab157.6 in (4003 mm)
Stabilizer Spread - Grade187.3 in (4758 mm)
OFPSOFPS cab meets SAE J2267
Width101.3 in (2573 mm)
Height157.6 in (4003 mm)
Area (tip to tip)3.8 ft² (1.15 m²)
Open54 in (1372 mm)
Note559D dimensions are on non-suspension trailer.
Height - Open - Excluding Rotation46.7 in (1186 mm)
Area (tip to tip)3 ft² (0.91 m²)
Weight - Including Rotation1907 lb (865 kg)
Height - Open - Excluding Rotation45.1 in (1146 mm)
Close5 in (127 mm)
Close4.5 in (114 mm)
Open48 in (1219 mm)
Weight - Including Rotation1911 lb (867 kg)
DEF Tank5 gal (US) (19 l)
Height - Open - Including Rotation68 in (1724 mm)
Weight - Excluding Rotation1411 lb (640 kg)
NoteAll specifications are approximate.
Weight - Excluding Rotation1407 lb (638 kg)
Height - Open - Including Rotation66 in (1685 mm)
NoteAll specifications are approximate.

Benefits and Features

  • The Cat® C4.4 ACERT™ U.S. EPA Tier 4 Final engine provides equivalent power (129.3 kW/173 hp) and optimized performance compared to C Series while minimizing overall fluid consumption
  • Advanced controls manage pump and engine interface to optimize performance and fuel efficiency
  • Leading hydraulic multi-functioning capability enables operator to lift, swing, and rotate grapple simultaneously without impairing performance

  • Auto idle minimizes fuel consumption when machine is on and not actively working
  • High capacity cooling system only pulls in cool external air to maximize efficiency
  • Electrically controlled variable speed fan is modulated to provide cooling only as required, reducing fluid consumption

  • Smooth hydraulic controls and superior balance provide market leading comfort and controllability
  • High capacity HVAC system provides dependable cooling and heating for maximum comfort
  • Improved stabilizer controls to equalize stabilizer actuation resulting in optimized uniformity of footing in varying ground conditions

  • Stabilizer movement alarm alerts bystanders of stabilizer movement
  • Pilot enable alarm alerts bystanders when pilot function is engaged
  • Ground level access of engine, fuel, pilot, and case drain filters as well as electrical service box

  • Reinforced fabricated booms with optimized cross sections designed to withstand heavy side-to-side delimbing applications and maximize lift capability
  • Field proven cooling system keeps engine and robust hydraulic system cool, extending component life
  • Larger diameter pins feature heavy-duty plating for improved durability and excluder seals to retain grease and keep free of SP contaminant

  • Single cylinder main boom has fewer parts to service than traditional dual cylinder lift system
  • Standard electric fill pump for hydraulic oil is at ground level for safe, easy service
  • Hinged doors provide industry-leading access to core components, daily check points, and service locations

  • Optimized Cat XT™-6 ToughGuard™ hose routings on GLK Series grapple designed to minimize loosening of fittings and improve hose life
  • Larger GLK Series cylinder pins and bushings reduce bearing stress by 25 percent
  • Available now in both a TW “Tapered Wide” and SN “Straight Narrow,” the GLK Series grapple is suitable for additional applications
  • Standard hold valves on GLK Series log grapples improve log retention
  • GLK Series grapples feature optional three port swivel which allows mounting of grapple saw
  • DLK426 delimber knives now have larger diameter pins that reduce bearing stress by 12 percent