• Shifting, through valves and displacement, provides either continuously variable gearing or more steps than traditional bicycles.

• Shifts smoothly under full power.

• Drive transmits power while pedaling forward and backward. Thus racers can power bicycle through turns by alternating short forward and backward pedal strokes. No slack or backlash occurs, in either direction. Ability to coast is maintained.

• Mechanism is clean and operates silently.

• Fewer moving parts (about 10 vs over 70), all of which are continuously bathed in clean lubricating fluid.

• Sealed systems
  Sealed systems
  Sealed systems are computer systems that are designed to be supplied as a sealed unit. The major benefits are security, reliability, ease of installation and upgrade, and locked down so users can't make changes that would compromise the integrity of the system. Many techniques may be used to build...
  
   require less maintenance than open chain system.

• Front-wheel drive and two-wheel drive systems can be implemented. (See Two-wheel drive)

• Drive can double as a hydraulic brake, eliminating the weight, cost, and maintenance of regular brakes.

• The hydraulic (hydrostatic) transmission could be useful for recumbent bicycle
  Recumbent bicycle
  A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position. Most recumbent riders choose this type of design for ergonomic reasons; the rider's weight is distributed comfortably over a larger area, supported by back and buttocks...
  
  s because the hoses may be easier to route than a long chain.

• Energy recuperation, storage and power assist could be added.

• Implementations to date are heavier than those of bicycle chain
  Bicycle chain
  A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics. Nickel also confers a measure of...
  
   and sprocket
  Sprocket
  A sprocket or sprocket-wheel is a profiled wheel with teeth, cogs, or even sprockets that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which are radial projections that engage a chain passing over it...
  
   designs.

• Though some of the components in a sealed hydraulic system maintain constant efficiency upwards of 95% in all conditions (see Hydristor
  Hydristor
  Hydristor is a joining of the words 'hydraulic' and 'transistor'. Thedevice invented by Tom Kasmer is based on the dual pressure balanced hydraulic vane pump invented by Harry F. Vickers in 1925.-Vane pump details:...
  
  ), the overall losses usually result in a power loss of about 25% (see Hydraulic machinery
  Hydraulic machinery
  Hydraulic machines are machinery and tools that use liquid fluid power to do simple work. Heavy equipment is a common example.In this type of machine, hydraulic fluid is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders and which becomes pressurised according to...
  
  ). In contrast, a chain-and-sprocket system loses efficiency in bad weather and dirt – from 97% for clean new components down to less than 80% when worn and dirty.

• The system may leak fluid causing a mess and eventual failure.

External links

• The Cyclo Pump Project: new Hydraulic Variable Transmission System specially designed for bicycles and human pedalling)
• Cannondale Jacknife (Hydraulic Concept Bike)
• Engineering Students Compete To Redesign The Bicycle: hydraulic and pneumatic designs
• First Annual Chainless Challenge: Fluid-Powered Bicycles
• The Contortionist by Dominic Hargreaves