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3D Dynamic Motion Analysis Bike Fitting

Every rider is unique in respect to flexibility, biomechanics and riding style. There are few generalizations that apply when truly fitting a rider to a bike. The Yellow Jersey Cycles bike fit studio uses Retül 3D motion-capture technology that allows capture of <1mm accurate data taken from key body points in real time. This data is then utilized to provide the most comfortable and efficient position to maximise performance. 

Used by pro teams Quick Step Floors, Dimension Data, Sky, Europcar and Orica-Scot Green Edge plus many of the world’s top triathletes, Retul is the most advanced bicycle fitting system available today.

The Retul system incorporates incredibly precise 3D motion capture technology, immediate reports, and a millimeter-specific digitising tool to provide the most accurate dynamic fitting solution in the industry. Retul is the official bike fit technology for many of the top pro cycling teams...

Retul Partners

Why Yellow Jersey Cycles and Retul?

Expertise in Bike Fitting
Yellow Jersey Cycles use the latest Retül 3D Bike Fitting equipment and are Retül certified fitters. 

Retul Certified Fitter

Bike fits must be dynamic

Most bike fit specialists fit riders in a static position. This is because the traditional tools of the trade — tape measures, goniometers and plumb bobs — don’t allow accurate measurements while the rider is pedalling. Retül captures the rider’s position relative to his pedalling motion, and therefore creates the most realistic replication of the actual pedal stroke and body position when out on the road and trails. 

Whether you are fitted on your own bike or using the Muve Cycle jig, the rider’s biomechanics are analyzed using the Retül system. Adjustments to the contact points of the rider can be made regardless of using the Muve or own bike. By scanning the finished position with the ‘Zin’ tool those contact points can be accurately determined and applied to either your own bike, or sizes and set ups can be recommended based on the collected data. This cannot be accurately achieved using standard equipment as it is impossible to accurately measure the stack and reach of a frame by any other method which is the key accepted method of sizing a TT bike and increasingly more often road bikes.

Measurements must be accurate
Measurements made by traditional tools have one thing in common: they are subject to human error and therefore can be inaccurate. Even slight inaccuracies can completely change the rider’s feel after a ride. Retül uses motion capture technology that is accurate to within less than a millimetre, creating true objective data, which can be utilized by the right fitter for the perfect biomechanical fit. Retül will always compare left and right for side-to-side differences. As a certified fitter, we ensure accurate placement of electrodes and therefore the most accurate data, knowledgeable interpretation of data and assessment of physical asymmetries and contributing mechanical issues that can create undesirable ranges. 

Biomechanics are best assessed in 3-Dimensional space
Fit data collected in a traditional 2-dimensional plane (i.e. video based systems) is fairly limited because the fitter can only look at one view at a time and those views stand as independent reference points. In order to make the best fit recommendations, the fitter must realise that the front and side view are actually interdependent reference points. In other words, the front and side view must be viewed simultaneously in 3-D in order to see how all the applicable movements of the body are working together. Retül is also the only system that captures and records this data for analysis.

A bike fit using Retül technology typically includes the following steps:

  • The fitter conducts an initial physical assessment of the rider, and at this point can address the rider's concerns about performance, pain, or any other issues the rider hopes to alleviate during the bike fit.
  • LED markers are strategically placed on eight anatomical points of the rider: the wrist, elbow, shoulder, hip, knee, ankle, heel, and toe.
  • As the rider pedals, Retül's sensor bar gathers real-time, three-dimensional data of the rider's pedal strokes and movements.
  • Retül's rotating platform allows the fitter to collect data for both sides of the rider without the rider leaving the bike.
  • The rider's data is compiled into a reader-friendly report for analysis by the fitter. The fitter can then assess the rider's position and make necessary adjustments.
  • The Zin, Retül's handheld digitizer, allows the fitter to digitally measure the rider's bike at 13-15 points, depending on the bike. The Zin can measure fixed points, contours, and curves, and provides a complete digital map of the bike.
  • The fit information is saved and stored on the fitter's computer.
  • The data includes the rider's personal profile, measurements from the fit, bike measurements, and the rider's final fit position.
  • The fitter will be able to access and print these records for comparison and tracking of historical fit data for the client.


For more information, watch this film about Retul 3D Dymanic Analysis Bike Fitting from BRITISH CYCLING

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