Ultimate Fit Bike

Purely Custom’s Size Cycle is the ultimate fit bike for all types of bikefitting. On a fit bike there are no limits to findingthe biomechanically optimal seating position. The necessary adjustments can be done on the fly, i.e. while the cyclist remains on the bike. Purely Custom has developed and engineered the Size Cycle in a perfect way, with the input of the renowned Serotta International Cycling Institute (SICI). Two versions of the Size Cycle are available and the Pro version discussed here includes a computertrainer allowing for watt-based fittings.t.

Area of application

  • Biomechanic fitting, not limited by the bike frame or components
  • Geometry and purchase advice
  • Bikefitting without a stock of products (e.g. components) – identification of the biomechanically best position
  • Different forms of standardization allow for scientific analysis


  • High-class workmanship for continuous usage in bikefitting
  • Exact scaling allows for a quick identification of the XY-coordinates
  • Quick and easy change of saddle and handlebar
  • Different stems can be simulated in no time and on the fly
  • Adjustable crank length
  • Seamless combination with the gebioMized pressure measurement technique and motion analysis
  • Water levels in both pedal arms allow for the exact analysis of the Knee over Pedal spindle (KOPS) position
  • Includes computertrainer and netbook for watt-based fittings