Jackson Kayak

Mark IV Flex Drive Upgrade

  • Sale
  • $999.00
  • Regular price $1,199.00


Meet the Jackson Kayak Flex Drive Mark IV, the latest innovation in the Flex Drive evolution. The only drive system on the market to offer a shallow water auto-retracting lower unit, a 3-position dagger board to accommodate a variety of depths, and a sealed above-water pedal system with intuitive forward and reverse operation – all wrapped up with Jackson Kayak’s industry leading warranty and customer service.

Faster, smoother, quieter, and more durable than ever before, the Flex Drive Mark IV gives you the power to get closer to the action.

So, how did we take something great and make it even better?

FASTER. The power to get you there. And back – quickly.

Jackson Kayak's 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. And we get to deliver a drive that’s smooth as silk, and faster than ever.

SMOOTHER & QUIETER. Because stealth matters.

The 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, we completely revamped the drive, and with the new belt driven system it’s quieter and smoother than all past versions of the FD.

MORE DURABLE. The Mark IV can handle anything you throw at it.

We wanted to figure out the best way to make our pedal system even more durable. So, what did we do? We looked to an industry that has been testing pedal technology, in all kinds of conditions, for well over a century – the bicycle. We started with ‘off the shelf’ bicycle parts and then put them in a closed, maintenance-free housing in a sealed oil bath. We then moved over to a serpentine belt system so that the entire system is stronger overall, and far more forgiving.

Just to make sure this system is as good as we think it is, we subjected it to hundreds of hours of freshwater and saltwater testing. Every box has been checked and double-checked. This gives us the confidence to offer a 2-year manufacturer warranty on the Mark IV, just like our previous Flex Drives.


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, we 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.

The Mark IV unit is not backward-compatible. The upper and lower units work in tandem. The updates to the lower include a larger diameter, reversed shaft and prop specific to the Mark IV system. 


In the Flex Drive 3D, we tightened the tolerances on the lower unit’s flexible shaft. This resulted in reduced vibration, and a dramatic reduction in noise on the water. We 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.

You can view the user manual here: https://hub.jacksonkayak.com/wp-content/uploads/2022/05/334_Belt-Drive-Manual-BV8.pdf

Made in the USA

71812 Kit; Upgrade Mark IV Upper, Lower & Prop