Treadlie Engineering has developed a unique and patent pending Continuously Variable Transmission (CVT) technology for bicycles.  Our company’s drive train differs from all other approaches by utilising a friction based V-belt driven Variable Diameter Pulley (VDP) system at the bicycle crank set and rear wheel. V-belt pulley drivetrains are well established and have a long standing track record in many industrial and mobile equipment applications, yet have to date not been used on bicycles because of the prohibitive width of traditional conical pulley assemblies to achieve useful gear ratios needed for cycling.