• Video analysis is two-dimensional, even with 2 cameras.  Motion Capture is three-dimensional which utilzies a 3-D spatial model. A small error is added to the measurement by not including all three dimensions in the calculation process. Small errors make big differences in bike fit

• Video cameras have a narrow field of view. Retul sensors have a wide field of view. This means that the video camera must be 1-2 meters further away from the rider to capture the full view of the rider.

• Video analysis places measurement markers on a small 2-D computer screen; Retul places measurement markers on the rider's body using easy to find skeletal landmarks.

• Video analysis requires that you manually trace each measurement after the fact with your mouse. Retul automatically performs all the measurements instantly with no manual work.

• Video analysis takes measurements off of one frame of video, which may or may not be a typical position of the rider. Retul averages all the measurements automatically from each stroke of the recording creating a highly refined model of the average movements of the rider.

What is Retül?

The Retül system uses infra-red LEDs (light emitting diodes) placed on the body of the rider in specific skeletal locations. A 3D scanner is then used to measure the location of each LED 29 times per second. This allows rapid collection of real information about a rider's position and movement while riding under load. The Retül analysis software records rider motion. Retul is used by a number of top level pro road and triathlon teams including Team HTC - Columbia, Commerzbank Triathlon Team, Garmin-Transitions, Team Sky, Lance Armstrong's Team Radio Shack and Team Trek K-Swiss for fitting and bike set up. Multiple Ironman world champion Craig Alexander and Ironman champion Norman Stadler both use Retul to optimise their comfort and power output on the bike.

Why use Retül?

1. Retül is FAST

Using the Retül system allows us to collect and analyse large amounts of rider data and quickly assess results of geometry adjustments to the bike. We can see the effect of all changes

2. Retül works in 3D

3D Motion capture allows us to study rider movements in 3 dimensions. A tracing of knee motion is produced automatically each time a set of measurements is taken allowing the fitter to make informed judgements regarding the adjustments needed. No other measurement system can record movement in both front and side views simultaneously.

3. Retül is dynamic

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

4. Retül uses averages

While we strongly dislike (to put it mildly) fitting philosophies that measure rider body dimensions and then guestimate "optimised" geometry without ever seeing the rider on a bike, Retül uses averages in a powerful way. 29 sets of results are taken from the rider during each second of the measurement period (normally around 15-30 seconds) and then averaged. This gives the Retül system a strong advantage over other motion capture techniques (such as video capture) as no two pedal strokes are the same. Video capture measures angles at a single point during a single pedal stroke. Retül measures angles constantly throughout many pedal strokes.

5. Retül is accurate

Measurements made by traditional tools have one thing in common: they are subject to human error and therefore can be devastatingly inaccurate. Even slight inaccuracies can completely change the rider’s feel after a ride. The general rule is that if you feel pain, something can probably be changed to eliminate that pain. Retül uses motion capture technology accurate to within less than a millimeter, creating true objective data which can be utilized by us for the perfect biomechanical fit.

What Retul Isn't

Retul is a measurement tool designed to provide a skilled bike fitter with highly accurate information with which to base fitting decisions. A key skill of a good bike fitter is observation. Rider bio-mechanics on and off the bike, rider motion and habits while riding, rider experience, fitness and goals all play a large part in the fit process. Retul is not a fitting system and the Retul software will not recommend or calculate bike geometry and set-up changes based on the readings it takes. A "Retul Fit" still depends greatly on the skill and experience of the fitter performing the fit. Bike Science fitters are highly experienced and trained to the highest industry standards which when combined with the advantages of the Retul system make for the very highest standard of fit available.