The Snek is an aluminium conical drum with a thread shape groove in which the 3 mm stainless steel cable rolls on and off each stroke.
As the groove is much longer than the stroke, it's possible to shift the propulsion cable to another part of the Snek with the special derailleur.
Since the Snek is conical, this results in a change of gear (255%). This unique patented driving-unit is extremely low-resistant, lightweigth, silent, clean, fluent and maintenance friendly.

Snek developments
The maximum diameter of the Snek has increased and the minimum diameter decreased, thus creating a larger gearing range. Each stroke results in 3.67 to 8.78 metres on the road.
Using the "old" Thys 222 rear hub the number of steps from the highest to the lowest gear was in six steps, with the new roller clutch hub this number has increased to eleven steps, resulting in a larger choice in gears. It's also possible to shift three gears at a time, with makes fast shifting easier.

In the accompanying illustration the concept of the Snek is shown in detail. The rear hub is equipped with the Snek. The propulsion cable (1) is wound one and a half times around the Snek, which ensures that the cable can't slip in any circumstance.

On the previous version of the Thys 222 the cable is pushed to another groove with a modified derailleur (2), which obtains a different gear.
The 2001 edition has an improved system.

The grooves that run diagonally along the Snek enable a smooth and fast shifting of gear.

The "lower gear" solution: to create a larger and lower gear range I had to change the system of shifting.

This alternative configuration shifts by rolling the cable further on or off the Snek. The cable is now attached with one end to the smallest part of the Snek.

By rolling it off you'll move to the higher gear.

While rolling it on, moves the cable into a lower gear.

This system enables you to increase the diameter of the Snek as much as you want, shifting is no longer limited by the length of your stroke.