2026 Bush Hog 4120

Bush Hog® FW4120 Flex-Wing Rotary Cutter
The FW4120 may be big, but it is no slumbering giant. Packed with upgraded, heavy-duty features that build on the legacy of the popular 2820 Series merged with the style of our 4115 and 5115 Series, these 20′ Flex-Wings are perfectly at home in a variety of applications like mowing pastures, cleaning up row crop residue, taking down tough CRP, and long days maintaining roadsides. Designed to cut heavy grasses and brush up to 4” in diameter, these cutters get the job done in virtually any mowing environment, except small neighborhood yards with garden gnomes. It would destroy the gnomes.

New performance and convenience features like heavily modified axles with an 8-point suspension, EZ-change blade bolts, and EZ-adjust leveling rods make your life easier. Our new and improved axles glide over obstacles, while significantly reducing shock loads for an improvement you can see and feel in the tractor seat. Heavily-braced, 7ga smooth-top decks shed debris and water for easier cleanup. Gearbox stand plates are thicker and gusseted for improved strength and durability. Hooking up to your tractor just got easier with a more adjustable tongue height range and quality of life features like rollover and clevis stops in our updated Perma-Level+ Hitch. Standard equipment includes Deck Rings and convenience features like EZ-lube drivelines, hydraulic hose handles to reduce slipping and improve ergonomics, and a Patent-Pending Driveline Assist that lifts and holds the weight of the heavy CV Driveline while attaching or removing from the tractor PTO. Then when not in use, the hoses and Driveline Assist can be safely stored in the tongue.

The New FW4120 20′ Flex-Wing can be equipped with Round Pans or a Shredder Bar, Perma-Level+ or 2 5/16″ Ball Hitch, 540 or 1,000 PTO Driveline, Center Dual or Walking Tandem Axles, Wing Single, Dual, or Walking Tandem Axles, 21″ or 25″ Laminated, 27″ or 29″ Air-Filled, or 25″ Foam-Filled Tires, and Single or Double Row Chains. And as with all Bush Hog® Rotary Cutters, the New FW4120 Flex-Wing comes with the industry’s first 10-Year Gearbox Limited Warranty. To show our confidence in the durability of the New 41 Series Flex-Wings, we have increased the Machine Limited Warranty to 2 years. That’s another reason why, “If it doesn’t say Bush Hog®, it just won’t cut it.”

Features may include:

Performance Features

• New Patent-Pending axle suspension reduces g-force shock loads by 37%
• Replaceable 1/2″ Cast Wing Skids for extended wear during heavy ground contact
• Angled rear deck section with 41% longer skids improve durability during side and backward impacts
• New durable Cast Leveling Rod Cams make adjusting deck pitch easier
• New Cast Walking Tandem Axles walk over the most rugged terrain instead of bounce through it
• Center section axle spindles are centered on the axle arm for equalized loading of vertical forces
• Grease fittings and spring steel bushings at axle pivot points for longer life
• Wing decks free float 22° down and 45° up without engaging the hydraulic cylinder for longer cylinder life
• Wing axles are adjustable left to right for variable row crop spacings
• New Rollover and Clevis Stops on the Perma-Level+ Hitch make tractor hookups easier
• Increased Cutting and Transport Height to mow down taller vegetation and easier loading on trailers

Construction Features

• Industry first — 3″ O.D. output shaft in cutting gearboxes
• Smooth-top 7ga deck plates are heavily-reinforced for years of trouble-free service
• Stronger gearbox mount and stand are built to withstand years of punishing mowing conditions
• Blade pans come standard with Hardened Hex-Head Blade Bolts and Bushings for easy blade changes
• 194% increase in axle arm section for substantially improved strength
• ASAE Cat 6 Input Drivelines and ASAE Cat 5 Wing Drivelines for strength in heavy cutting conditions
• Grease fittings in our E-Z lube drivelines align for reduced service times
• Patented oil sight windows make for quick and easy oil level checks
• Large, replaceable skids behind the tongue protect deck structure from ground contact

Safety Features

• Single or Double Row Chains to knock down flying debris
• Transport Lock supports the cutter while transporting
• Wing locks hold the wings stable when in an upright position
• Rollover and Clevis Stops reduce rotating and swinging hitch components while attaching to tractor drawbar
• 360° coverage around rotating drivelines
• LED safety lighting standard