Retul bike fit - Road Cycling UK

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Retul bike fit

David Zabriskie and other members of the new Slipstream team have been using the system recently to hone their fit.

Buying a bike is about much more than picking the one that pleases your aesthetic sensibilities the most, as it’s the fit that will largely determine how much enjoyment you will gain from your bicycle. So it’s important to get the right size in the first place, and here a quality bike shop will be able to help.

That’s the easy step, however. There are many parts to setting the bicycle up that contribute to the fit, and it’s quite easy to see how many people struggle to set their bike up to gain the most performance and provide comfort. With that in mind, we come rather neatly onto Retul, the latest in an increasing range of bike fitting techniques.

Retul is a state-of-the-art motion capture system that collects data from seven anatomical points in a cyclist’s riding position. The system provides millimetre-accurate data organised into an easy-to-read report. It’s dynamic, collects data while the rider is pedalling on the bike and requires just a computer and enough space for the system to operate.

The fit begins with an interview to gain a profile of the type of riding you take part in, your cycling history and your future plans. You might be planning an attack on the local road races or equally just want to get around the Etape quicker than last year. The process then moves onto measuring your body, with some exercises to realise your range of flexibility.

Cleat position, an often misunderstood but vitally important component of overall bike fit, is focused on. After this, it’s on to the real fun. Your bike is placed upon a static trainer and after a short duration of pedaling, your position is recorded by the sensors and the data translated by the computer to provide an A4 sheet packed with numbers. This information can now be used to adjust your current bike or be used to help design a new custom bike. For the former it may be a case of adjusting your stem choice, handlebar widths, crank length or seatpost layback.

How does it work?

The system uses infra-red LEDs (light emitting diodes) that get placed on the body in key movement locations. The active system flashes each LED discreetly as the infrared light travels from the LEDs on the body points to the sensor on the tripod. The sensor then triangulates the position of the LED in 3D space. The system can track these points to within a millimetre of true position.

It’s fast too. The system flashes an LED every 2.1 milliseconds. That’s 476 times per second or 476Hertz. The system takes a full set of body measurements every 34 milliseconds. That’s 29 full sets of body data per second.

Until recently, you would have had to travel to the US for a Retul fitting. Now, however, Bespoke Cycling (importers of Parlee and Lightweight) have been signed up as the first UK Retul specialists. A 2 to 3-hour session will set you back £175, but for a limited time only RCUK readers can get an introductory offering of £125. Foe details of the offer email or phone +44 (0) 207 7390119.

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