Bicycle Fitting Part II: The Science of Bike Fitting

By R2 Bicycles on

The science of bike fitting is based on a combination of off-the-bike and on-the-bike physical assessments by our trained bicycle fitters who have extensive knowledge of anatomy, physiology, and biomechanics. A proper bike fit takes into consideration the underlying bio-mechanical issues of the rider before assessing their position on the bike. Hip, knee, and ankle mobility, foot posture, back flexibility, neck and shoulder mobility, as well as core strength are some of the basic assessments that help determine your optimal ride position. A brief survey of these and other physical issues, injuries, medical procedures, and the goals and motivations of you the rider provide a framework with which we create the best bike fitting in Seattle to unlock your riding potential!

On the bike, our fitter will assess your movement and position, and combine this with the information learned about your body and goals to lay the foundation for your ideal fit. The fitter will incorporate the most cutting-edge research in cycling biomechanics into the development your personal bike fit. There is no one-size-fits-all recipe, but there are proven concepts in cycling biomechanics that are important to separate from the plethora of mythological bike fit rules. Major issues with your fit will first be identified and corrected during your on-bike evaluation. These include the appropriateness of component sizes, positions, and qualities, such as saddle, cranks, frame size/geometry, seatpost, handlebars, cleats/shoes etc.

The fitter will typically use the Guru Dynamic Fit Unit to allow rapid trials of variations of these components and the frame to test changes before implementing them or recommending equipment changes. Use of the BikeFit Saddle SwitchIt also allows for quick saddle changes for rider testing. Likewise, objective saddle testing with the Tekscan Pressure Mapping system can be utilized (see our next article, “Bicycle Fitting, Part III: The Technology of Bike Fitting” to learn more).

In the final stage of fitting, more precise adjustments are made to address any lingering issues that may be identified to ensure optimal ergonomic positioning on the bike for your riding style and goals. All details, like the location of controls, or handlebar and saddle rotation are addressed and corrected at this time. The final adjustments are measured and recorded for reference, in case future changes are needed.

“Bike-fitting relies on micro-assessing each individual using a multitude of criteria: rider feedback, ranges of motion, history of injury, pain concerns, sporting history, life-style, stress-level, training loads and, finally, riding aspiration and ambition”. –Phil Cavell, RCUK website, 2011


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919022 Aurora Ave N. Suite B
Shoreline, WA 98133