GMD 51 TC Series

GMD 5251 TC - Silhouette.png

Mow Wide, Mow Fast, Mow Clean

With 17’1” of cutting width, the KUHN GMD 5251 TC proves to be a worthwhile investment for any large farm or custom operation looking to increase profitability by doing more work in less time.

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The KUHN GMD 5251 TC center-pivot disc mower adds to the range of trailed GMD models with 17'1" of working width. With a center pivot, the mower is able to get all the hay to the left, right or anywhere in between for maximum productivity. This machine provides high work output and is perfectly adapted to medium-sized tractors. This model features the lubed-for-life Optidisc® Elite cutterbar equipped with the Fast-Fit® quick knife attachment system. All discs are driven from the center of the cutterbar which simplifies drivelines and significantly reduces maintenance. The integrated narrow transport system allows for rapid transition from field to field and improved safety on the road.

Your benefits

The Optidisc® Elite Cutterbar: A Clean and Consistent Cut


Lubed-For-Life Optidisc® Elite Cutterbar

The Optidisc® Elite cutterbar provides a flat, streamlined profile so that soil and crop residue do not accumulate and material flows smoothly, even in heavy, difficult crop conditions. These mowers come standard with the Fast-Fit® quick release knife system. Optidisc Elite cutterbars are designed and tested with a zero oil change interval. The highly-polished gears and synthetic gear oil ensure that this system does not require any regular internal maintenance, eliminating the need for cutterbar oil changes throughout the life of the machine.

Differential Disc Spacing

The innovative design of the Optidisc Elite cutterbar offers exclusive differential disc spacing.
  1. Less Distance for a Clean Cut: Narrower spacing at diverging discs provides greater knife overlap, which results in a clean cut, even when the grass is short or light.
  2. More Distance for Easy Crop Passage: Wider spacing at converging discs provides more space for the crop to pass. Cut crop is quickly carried away from the cutting area, greatly improving the cut quality.

Standard Fast-Fit® Knives

The Fast-Fit® quick-release knife system allows an operator to rapidly change out cutting knives with the use of a simple tool, yet still retain optimum cut quality and knife life. With Fast-Fit, an operator can achieve up to 50% time savings over a standard system.

Protectadrive® Disc Bearing Stations

  • Protectadrive® Safety: Every minute saved during the hay season is precious. Ultimate protection, from the externally removable Protectadrive disc bearing stations, provides maximum reliability and quick service. In the event of an impact between a disc and an obstacle, the shaft holding the disc can shear just above the bearing. This is thanks to its carefully dimensioned shear groove. As a result, the gear teeth are protected.
  • Extra Rigidity Where it Counts: Disc bearing stations are attached by bolts that pass through the entire cutterbar. This is an exceptionally strong and secure attachment with no risk of mount being torn out of the cutterbar in case of shocks. The disc drive pinion is held precisely in place, all resulting in excellent reliability and reduced maintenance costs.
  • Gear-to-Gear Power Transmission: Gear-to-gear power transmission, a staple of all KUHN disc mowers, allows for maximum power to be transferred through all gears in the cutterbar. Unlike other gear cutterbars, equal sized gears throughout reduces torque on the gear teeth and leads to unsurpassed reliability and longevity.

Adapts to Various Terrain


Pro-Active Lift®

This maintenance-free system allows the machine to quickly adapt to abrupt changes in terrain or when an obstruction is encountered in the field. The cutting head is able to move up and back simultaneously, dissipating the force of any impact and providing space to clear the obstacle. This unique design reduces scalping to preserve crop stubble and helps protect the machine from potential damage. A slotted linkage on each side provide guidance for the header and eliminates the need to run the hydraulics in the float position.

Constant Float Suspension

The header is suspended on each side by a long, large-diameter spring that provides a constant range of flotation. The floating head lifts up and back, and can oscillate from side-to-side, to closely follow the ground contours and conform to irregular terrain. This reduces the amount of missed crop in the field and helps keep dirt out of the harvested crop.

Adjustments to this system are very simple. Simply tighten or loosen the springs on each side to reduce or increase ground pressure and improve flotation.

Superior Maneuverability

The heavy-duty Gyrodine® gearbox is designed to withstand the most severe pull-through force from the hitch to the machine. The swivel design allows in excess of a 90° turn while keeping the PTO driveline straight. This design also allows extremely tight turns for clean, square corners while minimizing PTO vibration and wear. Choose a drawbar swivel hitch or a 2-point attachment on the 51 TC Series disc mowers. Side guards on the drawbar hitch protect the body if contacted by the tractor tire in a very tight turn. This reduces the chance of costly repairs and helps maintain the appearance of the machine.

Simple Design and Easy Service


Narrow Transport Design

A built-in lengthways transport position allows operators to quickly go from field to field and reduces risks of accidents, or operator’s fatigue if traveling long distances. Wheels in forward position allow for an excellent center of balance, with easy entry into fields having narrow gateways.

Direct, Center Drive Design

The direct drive design provides easy access for servicing and fully eliminated belts. The center drive design keeps the driveline design simple. The central gearbox pivots to left or right as the machine switches sides. Reliability is greatly improved when working in longer, tough or lodged crops. Also, unlike competitive models that require daily greasing, the driveshaft to the cutterbar uses maintenance-free U-joints. These joints reduce overall maintenance and eliminate excessive wear from improper maintenance.


The gearbox drives the central discs of the cutterbar, reducing stress on the cutting unit. The two drums separate the crop flow to form two swaths, if desired, or a wide, 13’1”, continuous swath can be formed for maximum drying.

Convenient Height Adjustment

The height change adjustments are fast and simple, and do not require tools. Cutting height is set using a special turnbuckle that adjusts easily with only modest effort. A convenient gauge on the turnbuckle shows the cutting height for precise field adjustments.

Steel Side Sheets

The steel side sheets provide a definitive line between cut and uncut crop. This makes the subsequent pass easier to follow for the operator and also gives the machine a finished look.




Working width
Transport width
Number of discs
Disc type
Blade retention system
Removable Protectadrive® disc bearing stations
Hydraulic lift mechanism
Cutterbar suspension
Safety guards
Cutting height
Suspension travel
Average swath width
Primary PTO
Secondary PTO shaft
PTO speed
Friction slip clutch
Minimum PTO power requirement
Required tractor hydraulic connections
Side sheets
Road lights and signaling
Machine weight approx.
17'1" (5.2 m) 17'1" (5.2 m)
17'3" (5.3 m) in transport 9'6" (2.9 m) in transport
12 12
Optidisc® Elite Optidisc® Elite
Fast-Fit Fast-Fit
Standard Standard
Standard Standard
Constant Float® suspension with Pro-Active Lift® Constant Float® suspension with Pro-Active Lift®
Standard Standard
1.4" - 2.6" (35 - 65 mm) 1.4" - 2.6" (35 - 65 mm)
15.75" (40 cm) 15.75" (40 cm)
Single swath: 13'1" (4.0 m)
Dual swath: Two 6'6" (2.0 m) swaths depending on crop conditions
Single swath: 13'1" (4.0 m)
Dual swath: Two 6'6" (2.0 m) swaths depending on crop conditions
Trailed, must choose drawbar or 2-point semi-mounted, Cat. 2 or 3N Quick hitch compatible Trailed, must choose drawbar or 2-point semi-mounted, Cat. 2 or 3N Quick hitch compatible
12.5L - 15SL 12.5L - 15SL
1-3/8" - 21-spline 1-3/8" - 21-spline
Friction slip clutch standard Friction slip clutch standard
1,000 rpm 1,000 rpm
Standard with friction slip clutch Standard with friction slip clutch
90 hp (67 kW) 90 hp (67 kW)
2 DA 2 DA
Steel Steel
Standard Standard
5,445 lbs (2,470 kg) 6,615 lbs (3,000 kg)



Customer Spotlight: GMD 51 TC

  • GMD5251TC TrappFarms
    Kenneth Trapp Jr. Tifton and hay producer

    "It’s big! The GMD 5251 TC is very well designed and the construction is second to none. We travel a lot between locations and safety is a primary concern, so the ability to transport in-line is something I’ve been waiting for," stated Trapp, "This was a top selling point. It’s very well engineered. Transition in either direction is quick and easy. It also opened up space in our equipment barn."

    Read this review

All the testimonials

Available applications: GMD 51 TC

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