CyclingNZ Home

From Pro racer to Pro fitter

Wedge it

Bike Fit Technology - Excellence at Exceed
21 Jul, 2009

With the advancements in bike fitting taking a quantum leap in the last couple of seasons riders are starting to see the huge benefits that can be derived from being in the perfect position on the correctly sized bike. caught up with Aucklander Karl Murray from Exceed bike fit who runs the Retul system and got to the bottom of what it is all about.


CNZ: Karl, how did you get involved with Retul?

KM: While fitting Jo Lawn to her TT bike, I was talking to her husband Armando Galarraga about opening a fit studio and he knew Franko Vatterott from RETUL.  So after a year of using the system through a bike shop, I purchased RETUL and have opened Exceed Bike Fit Studio.

CNZ: You have just opened at the top of New North Road & Symonds Street offering fits and coaching, this must offer a good service to riders wanting to step up their performance?

KM: Itís the perfect place for me to enhance a riderís cycling fit & knowledge, as I donít only make changes to their position,  but I explain why they were made and how they can improve their comfort, posture and technique on the bike.

CNZ: OK - Tell us, what really is Retul? I hear people say "I offer a Retul Fit" or "I am going to get a Retul fit." Does a Retul really do a bike fit? Is it a fitting system? Can you clarify this for our readers? 


KM:People have referred to RETUL as a bike fit system because it is made up of different components that acquire real-time 3D data. However, it is a tool which allows fitters to see realistic movements and then make their OWN decisions when applying intervention to your bike set-up.  All of the fitters I know use a variety of tools and subscribe to a variety of techniques. I guess you can say that each fitter develops a fitting routine.


CNZ: Can you explain a little more about what "3D Data" is? Does this take a picture or video? Do you see the cyclists actually riding their bike in the date you collect?


KM: The system captures coordinate data of infrared markers (on the body) from multiple angles. Through camera synchronization, a 3D numerical model is formed of the rider.  This is called motion capture, the re-creation of a real 3D body through multiple views. This allows for full integration of all 3 dimensions of movement on a bike, of which the transverse plane is becoming the most important. What you see on the computer screen is a dynamic display of the rider as a stick figure. That is valuable because our software (loaded with normative data ranges for all cycling disciplines) generates an immediate report of pedaling mechanics for the fitter to utilise.


CNZ: How is RetŁl different than the motion analysis systems (i.e. video) most local shops offer?



  • Video analysis is two-dimensional, even with 2 cameras.  Motion Capture is three-dimensional which utilises 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 fitting.
  • 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 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 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.

CNZ: What was it that sparked your initial interest in bike fits? How long have you been doing bike fits? Also give us a little information about your background which has influenced your bike fitting.

KM: Bike racing, of course!!! - The need for speed. I wanted to improve my position and in doing so found more power and comfort which resulted in going faster.

When you look at the researchers in any field, most of them are there for selfish reasons, trying to better themselves through science. In 2006 I learned the skill of bike fitting at the Serotta School of Pro bike fitting. I returned from New York with a huge amount of knowledge.  Most of my initial work was in defining the bio mechanics while riding and trying to understand what physiological factors determine success.  Then I was slowly able to learn the ways that a bike fit can resolve/prevent pain in certain areas of the body.

Since being thrown into the fitting "fire" in feburary 2005, I have done 100ís of commercial fits. I have used RETUL to fit people like Jo Lawn, Cam Brown, Myron Simpson, Kieran Doe and many other top NZ athletes


CNZ: You are well known for being one of only a few whom understand the fundamentals to wedging cleats.  Can you share the reasons for you using a cleat wedge? 

KM: There are many reasons to use a cleat wedge, far too many to list here. But what I would like to say, in general, is when a cleat wedge should NOT be used. I firmly believe a fitter should never over - correct the ankle to have some sort of desired effect on the knee tracking.  Correct to "neutral" and stop.


CNZ: Your accomplishment that you are most proud of is? a fitter?


KM: I really enjoy enhancing the cycling experience for normal, everyday riders. Nothing inspires me like getting good feedback from clients. Nearly everyone who comes through the Exceed Bike Fit Studio sends me referrals, which is the best way to grow and measure your business's long term value.


CNZ: Tell us about your most interesting bike fit.


KM: I coach a lady who has had a lot of surgery that affects her bike fit so I have tweaked her fit a few times as we have changed pedals, seats, bikes and posture over time. She is off to the World Masters Games in Australia later this year.


CNZ: Your favorite cyclist in the peloton today is who, and why?


KM: I tend to favor the young guys because they are so bright-eyed and ready to learn. They haven't been beaten down with some of the BS that goes on in cycling and therefore are so optimistic about the future of our sport. Some of the young guys I coach have the right attitude to push for a spot on a pro team.


CNZ: If there was one thing you could change or improve on bikes, what would it be and why?


KM: UCI rules as they affect very short and very tall people unfairly.


CNZ: Any new developments on the Retul front?


KM: 2 things,

#1 is the ZIN see >

#2 is a wireless version of the Retul where you can collect data from a rider while driving along side them, see>


CNZ: One piece of advice you can offer to bike fitters today?


KM: Keep an open mind. What might work for some, may not work for others. Everyone's body is different. Tap into the experience of your elders - no amount of education can trump practical experience. Also, after a fit, keep the communication lines open while riders are adapting to their new position to enable any questions to be answered and fears dispelled.


CNZ: Any additional comments in parting that you would care to add?


KM: I love advancements in technology within the bike industry. My hatís off to all those innovators who dig the sport enough to devote their work lives to making it better for all of us.


Karl can be contacted here for a bike fit:








Click to enlarge...
The studio

Latest News
Last month‚Äôs ferocious weather that wreaked havoc on the West Coast has seen many hours of effort to ensure this weekend‚Äôs double header rounds of the Calder Stewart Cycling Series in Hokitika can go ahead. ‚ÄúThe weather gods poured more bad news on the proposed round three course in >>
As the season fast approaches, take a minute to learn about which world class athletes will be using Crankbrothers products in 2019 and beyond! New for this season, we are excited to welcome the Trek cross country superstar duo of Emily Batty and Yolanda Neff along with the rest of the Trek >>
Team Jumbo ‚Ä" Visma‚Äôs Primoz Roglic has won the 54th edition of Tirreno-Adriatico in style, with a final stage Individual Time Trial performance to remember. His near-perfect technique on the San Benedetto del Tronto 10km out-and-back course saw him overturn a 25-second deficit to his closest >>
Latest Articles
Six years ago, Christchurch mountain bike phenomenon, Anton Cooper, set a race record in the famous Gazley ҆KODA Karapoti Classic that many thought would never be broken. The former world and Commonwealth champion slashed seven minutes of the previous record to clock 2hrs 07min 57secs around the >>
We are delighted to share the news with you that fizik‚Äôs 2020 sponsored teams are confirmed! Along with our strong presence at the top of road cycling, we have a full set of mountain bike teams, competing in Cross-Country, Downhill and Enduro. MOUNTAIN BIKE TEAMS In Downhill, Commencal >>
What is the first e-road by LOOK? This is a bike that is the result of our mastery of carbon, which allows us to offer a frame that is both lightweight and durable, manufactured in our own production facilities. This is also a bike that has just continued a story that has been written at the >>
LOOK 2018
ISM Saddles
Morgan Blue Cleaning
 Photo Gallery
Tour de Femme Tour de Femme
Daniel Gate bioSPORT Crite Tour de Femme
Home Kiwi Riders Sports Science Beginners Articles Riders Reports Tech Corner Contact
© 2020 | Login | Design by OnfireDesign