The Fendt TriSix was a six-wheel prototype tractor built in 2007 to test whether wheel-based machines could match the traction of tracked tractors at power levels above 500 hp.
Why Fendt Needed More Than Four Wheels
By the mid-2000s, standard four-wheel tractors had reached a power limit. As engine output climbed beyond 400–500 hp, four contact points were no longer enough to transfer that power to the ground without wheel slip and soil compaction. Making the machine wider to add traction pushed it beyond legal road width limits.
Tracked tractors delivered the traction, but came with higher purchase and maintenance costs, and caused surface damage during turns. Fendt engineers needed a configuration that matched tracked traction without those trade-offs.
The TriSix was the answer: a third axle and a sixth wheel, keeping the machine within road width while multiplying ground contact.
Fendt TriSix Specs
The TriSix ran on a MAN 12.4L six-cylinder diesel engine with a net output of 500 hp (372.9 kW). During development, Fendt tested configurations exceeding 530 hp.
The drivetrain was full 6×6 six-wheel drive. All six wheels carried identical 650/65R38 tires. The fuel tank held 1,360 liters, sized for large-scale field operations. Hydraulic pump flow reached 219.9 liters per minute.
The cab was the Fendt X5 with air conditioning. The machine also included anti-lock braking (ABS), which was uncommon on tractors of this power class at the time.
Debut at Agritechnica 2007
Fendt unveiled the TriSix at Agritechnica in Hanover, Germany, in November 2007 — the largest agricultural machinery trade fair in the world. The machine was presented as a working prototype, not a production announcement. It drew attention from engineers, manufacturers, and large-scale farming operations across the industry.
Why Fendt TriSix Was Never Mass-Produced
Fendt did not move the TriSix into production after the prototype stage. A third driven axle added driveshaft components, differential units, and control systems that raised both production cost and mechanical complexity.
The market above 500 hp was also narrow. Operators in North America and Australia who needed that level of power already used articulated four-wheel-drive tractors or tracked machines from established manufacturers. Competing in that segment with a three-axle configuration carried significant commercial risk.
Fendt determined that the prototype’s value was in what it revealed about power transmission — not in the machine itself.
From TriSix to VarioDrive — How a Prototype Changed Fendt Transmissions
Distributing over 500 hp across six driven wheels exposed the limits of standard gearboxes. The project required a drivetrain that could manage power flow continuously, without fixed gear steps. This led Fendt to develop its continuously variable drivetrain, known as the CVDT, with the internal designations ML 400 and TA 400.
That system became the VarioDrive, a continuously variable transmission (CVT) that independently controls power distribution between front and rear axles. It removes fixed gear ratios entirely, keeps the engine at optimal efficiency across all speeds, reduces slip, and lowers fuel consumption.
Fendt integrated the VarioDrive across its standard tractor lineup, extending the wheel tractor portfolio to 500 hp and applying the same CVT logic to its tracked machines.
What Happened to the Fendt TriSix After 2007
The prototype was retired after Agritechnica. No production units were built. The machine itself left no direct successors, but the engineering work it generated did. The VarioDrive transmission, developed as a direct result of the TriSix project, remains in production across the Fendt lineup today.
