Direct Drive Differential™


The Direct Drive Differentialtm is a gear assembly that significantly enhances the capabilities of zero turn mowers.  Most zero turn mowers have two transmissions – one for controlling each drive wheel. This new concept also requires two transmissions, but one controls vehicle speed, while the other controls vehicle steering.

The propelling input drives both wheels at exactly the same speed – forward or reverse.  The steering input adds speed to one side while reducing speed to the other side.  The two drive wheels are no longer independent – they drive exactly as defined by the inputs.  This eliminates any possibility of one wheel breaking traction and spinning, causing turf damage, unless both sides simultaneously break traction.

Operation of zero turns and of sharp turns is simplified in a way that eliminates much turf tear. Operation in straighter usage is similar to that of current operation – where often slight turns are made by holding one control unchanged while varying the other either direction.

To see prototype demonstration, visit:




Special Features

  • Straight line driving with one-hand control
  • Steering control speeds up on one side while simultaneously slowing down the other side
  • Zero turn capability using one control
  • Eliminates inside wheel pivoting on turns – preventing turf damage
  • Eliminates single-side traction breakaway on wet spots – preventing turf damage
  • Eliminates single-side traction breakaway on side hills – preventing turf damage
  • Eliminates factory adjustment for side-to-side speed match
  • Eliminates customer dissatisfaction when side-to-side speeds are not matched (Yes, this does happen and is especially irritating in reverse!)
  • Unique, low-cost parking brake available – patent pending
  • Easily adaptable for steering wheel use
  • Easily adaptable to hybrid vehicles (i.e. hydraulic propel and electrical steering)
  • Easily adaptable to all-electric applications
  • Facilitates technology evolution – with PRODUCT DIFFERENTIATION
  • Technology is scalable and applicable to many other applications





Product Description

The Direct Drive Differentialtm is a new technology designed to increase vehicle controllability to eliminate single-wheel traction breakaway and to make that annoying inside wheel pivot damage difficult to even accomplish.  This concept significantly increases vehicle traction capability and decreases turf damage.  The effect of this design is similar to that of positraction, but it shifts the power away from the low-traction side before the “slip” occurs.

This technology would be useful in many applications, including zero-turn mowers, motorized wheelchairs, tractors, specialized harvesters, ATVs and other agricultural or construction equipment.

The Direct Drive Differentialtm is a gear assembly (gearbox) with two inputs and two outputs.  The outputs drive the wheels.  The gearbox contains two planetary gearsets that are interconnected in a unique manner such that one input controls speed (forward and reverse), and the other input controls turning by increasing output speed on one side while decreasing output speed by the same amount on the other side.  This offers a driven differential that is controlled – thus a Direct Drive Differentialtm

Product Specifications

  • Two identical planetary gearsets
  • One propelling input gear and shaft assembly
  • One steering input gear and shaft assembly
  • One idler gear and shaft assembly
  • One central drive shaft
  • Two planet carrier outputs
  • Bushings and fasteners
  • Gearbox enclosure and mounts


The  Direct Drive Differentialtm  is covered by United States Utility Patent: 9,493,186















The  Direct Drive Differentialtm  is covered by United States Utility Patent: . 9,316,301
















For additional information, licensing opportunities, and a full prospectus on the  Direct Drive Differentialtm  contact:




VP of Business Development