Posted in Cycle
A cyclist in position before the Retul bike fit

Words by Morgan Callas

Why a bike is fit important?

An over the top description of riding a high performance bike that is incorrectly fitted would be like buying a Ferrari that hasn’t got an adjustable seat! Your just not going to get the enjoyment you expected from your purchase because it feels uncomfortable to ride and its limiting the potential performance.

Understanding your muscles

All muscles in the body work in pairs and if working equally will work for longer without building up pressure on the joints and cramping. Muscles also work better if they have full range of movement without restrictions.

An example of a restriction would be riding with the seat too low. This will cause the glutes to be overworked, possibly lower back pain and pressure on the knee joint. The rider in this position would also be working twice as hard to make the distance that they could potential achieve without the restriction in movement to the body. This is usually something every cyclist has experienced at one point in their cycling biography and the most obvious answer to this problem would be to raise the saddle. But how far? You could put the saddle up too high resulting in hyper-extension and over extension on the leg muscle group. It is very easy to hesitate a guess by the way it feels in motion or you could ask a professional in a bike shop who would more than likely offer advice but usually this may be opinion or a generic static bike fit. Without a doubt this would be a great place to start but everybody’s has a unique body structure tailored for them. Hip height varies from person to person, you may have longer legs and a shorter body when comparing body geometries with someone of similar height to you.

A static bike fit will consist on measuring up the body and checking the body’s parameters of movement in a stationary position. This may help to get an understanding of the leg lengths but it will be difficult to measure all three contact points (Hands, hips & feet) at once without the body in motion.

The Retul bike fit

There are many tools on the market that can help place a rider in the ideal riding position but none do it with 3D motion analysis tools like Retul. The Retul equipment takes measurements from both your left and right sides (as these are nearly always different). Vertical and lateral measurements are taken giving a complete 3D picture of how you cycle and capturing all the key measurements from knee angles, back positioning, elbow positing, how your foot moves through the pedal rotation, your hip positing etc. This creates very accurate data that the fitter then uses to analyse how you ride, how each measurement is affecting your ridding and where the optimum position for you is.

A cyclist in position before the Retul bike fit

A cyclist in position after the Retul bike fit


Vantage 3D Motion Capture System

This is the system that Wiggle Works currently uses to conduct post purchase bike fits. It is a really high tech tool that allows me to see how all of the applicable movements of the body are working together. The Vantage System collects data from the frontal plane (any vertical plane that divides the body into ventral and dorsal (belly and back) sections)) and sagittal plane (a vertical plane which passes from anterior to posterior, dividing the body into right and left halves) of a rider and plots the results as averages every 5 seconds when the cyclist is in motion.

Retüls motion sensors simultaneously gather data on multiple angles of the rider in three dimensions so that I can not only see measurements such as knee and hip angles, but also lateral knee tracking and hip lateral travel. The Vantage system gives you neutral fit angles to work towards for each discipline, time trial, mountain biking and road cycling. Based on both neutral fit data and motion sensor data I will make adjustments to the position of your bike, one at a time, so you can then try out the new positioning in small increments. This step is repeated until the optimal fit specifically for you is achieved.

Get fitted with Wiggle Works

The complete fit will take 2-3hrs and the participant will finish the session with a copy of the fit report and Zin of the bike (bike measurements with sub-millimetre accuracy of each crucial component) for them to refer back to if any component of the bike have been altered in the future.