New Cat® Track Feller Bunchers Feature Bigger, Tougher Undercarriage and More Horsepower

- Advertisement -

The new Cat® B Series track feller bunchers, introduced at the Oregon Logging Congress in February, feature a new, upsized undercarriage, more horsepower and a new hydraulic design for improved multifunctioning performance.

“Major enhancements to these track feller bunchers will give loggers faster cycle times, more uptime and longer machine life,” said Keith Hicks, Caterpillar Forest Products product performance engineer. The Cat 522B is a leveling machine for select or clear-cut logging in rough, steep terrain. The Cat 521B is a non-leveling model best for plantation thinning, swamp logging, medium production clear cut, and high production biomass applications.

All the undercarriage rolling components of both models have been upgraded to D7 size hydraulic excavator type. “Track shoes, link assemblies, idlers, track rollers and undercarriage frame structures have all been upsized. Undercarriage life expectancy even in tough terrain is going to increase significantly,” Hicks said.

The B Series limited tail-swing machines have the same industry-leading strong drawbar-to-weight ratios as the previous models and a full 35 in. (889 mm) of ground clearance from front to back — 2 in. more than the previous models. “Strong drawbar pull, along with even better ground clearance and the ‘open tunnel’ undercarriage design make for a highly maneuverable machine that easily climbs steep slopes,” Hicks said. The 522B can be ordered with a high drawbar option, boosting drawbar performance by 13% for logging in extremely demanding steeper terrain.

The swing capacity of 61,000 lb-ft (82.7 kNm) is another advantage of the Cat track bunchers when working on steep slopes. “The strong swing torque gives the operator the ability to swing big loads up slopes,” Hicks said. “The combination of swing and lift capacity with improved multifunctioning will reduce cycle times and increase production. And the balance between lift and tipping load capacity gives the machine the stability loggers need to be safe working in steep conditions.”

- Advertisement -

A complete re-configuration of both the implement and travel hydraulic circuits and new compensator valve spools smooth out and improve multifunctioning. “The operator can maintain a steady rhythm when activating several functions simultaneously,” Hicks said.”A more efficient hydraulic system also requires less horsepower, so fuel consumption is reduced.”

The hydraulics can be configured for either high or low flow attachments. The Cat HF B Series felling head operates on low flow. This frees up oil to run other machine functions while simultaneously maintaining maximum open and close arm speeds.

The B Series machines are equipped with the Cat C9 ACERT™ engine delivering 303 hp (226 kW) of gross power, 20 hp more than the previous models. The C9, which meets U.S EPA Tier 3 emission regulations, is a common engine design with a proven track record of reliability and durability in the woods.

The 522B features the only two-way simultaneous leveling system in the industry. This unique three-cylinder design significantly reduces stress loads into the leveler structure, lower frame and track frames, and lasts longer than two-cylinder leveling systems.

The cab has all the convenience and comfort features built into other Cat forestry machines. The monitor has been downsized slightly to improve the operator’s line of sight out the right front corner of the cab. “The operator has a clear view of the work tool and area to the right side of the cab for lining up a cut or repositioning the machine and linkage,” Hicks said.

For more information visit