Jackson Flex Drive Mark IV Upgrade Kit


4 in stock

Jackson Flex Drive Mark IV Upgrade Kit

SKU 71812 Categories , , Brand:


Includes Upper, Lower, and Prop


The only drive system on the market to offer a shallow water auto-retracting lower unit, three-position dagger board to accommodate a variety of depths and a sealed above-water pedal system with intuitive forward and reverse operation.

Faster, smoother, quieter, and more durable than ever before, the Flex Drive Mark IV gives you the power to get closer to the action. Our latest upgrades have made the drive more efficient and that has allowed us to use a more aggressive prop. Specifically, the Flex Drive Mark IV is powered by a 3:1 pedal drive input fed into a 4:1 spiral bevel gear pair. The result? You get more speed from every rotation of the pedals.

Jackson has upgraded the bearings, increased the diameter on the flex drive cable and reversed the rotation of the drive all in an effort to make sure what is under the water is whisper quiet. On the upper, they completely revamped the drive, and with the new belt driven system it’s quieter and smoother than all past versions of the FD.




  • Faster than ever. The latest upgrades have made the drive more efficient, and that allows us to use a more aggressive prop for faster speeds
  • 3:1 Pedal drive input, fed in to a 4:1 spiral bevel gear input
  • Smoother. The new belt driven system and increased diameter in the FD cable pedals smoother than all previous versions.
  • Quieter. Upgraded bearings keep the drive whisper-quiet.
  • More Durable. Industry-tested technology make the FD tougher than ever.
  • Virtually Maintenance Free. The upper unit is now in a sealed oil bath – no more topping up the grease. All you need to do is make sure it is rinsed after every outing.
  • Tested Tough. Every drive is checked and double-checked for quality.
  • Two-Year manufacturer warranty.


The upper unit has been completely redesigned. It now features a serpentine belt-driven system and uses ‘off the shelf’ bike parts that have been in use for decades. By moving this direction, they were able to increase speed and durability, all while using parts that have been industry-tested to perform in the worst conditions possible.

The new Mark IV Drive is maintenance-free and ready to use immediately. The sealed oil bath surrounding the internal gearing on the drive eliminates the need for maintenance, and because the crank arms are factory-installed to the proper torque rating, you’re ready to start pedaling!

The Flex Drive Mark IV gear ratio is a 1:12 system, and the propeller has been fine-tuned specifically for this system. The upper unit is still a sealed system, which means no gears or moving parts are below the waterline.


In the Flex Drive 3D, Jackson tightened the tolerances on the lower unit’s flexible shaft. This resulted in reduced vibration, and a dramatic reduction in noise on the water. They have continued the Flex Drive evolution with the Mark IV, adding a thicker, more durable drive shaft and reversing the rotation of the prop to work with the newly designed upper unit.

Since the lower unit is not a sealed system, the water is able to drain easily.

Additional information

Weight 40 lbs