Carfrae Works with Retul to Accomplish Position Changes on New Felt

2010 Ironman World Champion Mirinda Carfrae has been working with Retul over the past year on her evolving time trial position.  Carfrae understands the performance benefits of improving her bike position, and trusts Retul's accurate and precise measuring capabilites for the task. 

At the Endurance LIVE Event in January, Retul experts Mat Steinmetz and Todd Carver presented Retul 3D Motion capture-data, and previewed the upcoming Frame Finder release wih the help of Carfrae and Felt, the new bike sponsor for Carfrae this year. 

  
Mat Steinmetz, Mirinda Carfrae, and Todd Carver on stage at Endurance LIVE in San Diego

Mat Steinmetz of Retul comments on working with Carfrae, her 2010 Kona win, and changes to her position in 2011:

RECAP OF 2010 CHANGES

Carfrae's biggest change on the bike was to move to 650 cc wheels from 700 cc wheels.  Bike companies and athletes alike often make compromises to rider position and frame geometry in an effort to squeeze 700 cc wheels on the bike of a smaller athlete. 

The other significant change for Carfrae in 2010 was her aerobar setup.  The changes in posture allowed Carfrae to better support herself in the aero position. 

With the 2010 Kona win, these changes proved to be effective for Carfrae, and she commented that she had never felt more comfortable on the bike. 

WHAT'S TO COME IN 2011

Carfrae is now riding Felt, and Retul worked with Felt on the intial setup and fit of the 2010 DA.  Jim Felt contacted Retul requesting Carfae's fit data from her previous bike, the Cannondale Slice, so that her fit coordinates could be matched on her new Felt.  Felt engineers are also using Retul data to design the new 650 Felt DA.    

Once Carfrae received her new DA, there were still a few changes to be made.  The front end was dropped down one centimeter, and the armrest moved forward one centimeter, giving Rinny more drop and reach.  Cranks were changed to 165 (she was previously riding 167.5).  Studies have shown that maximum power output is not affected by crank lengths ranging from 120-220 (Martin et al 2001).  There is a significant biomechanical advantage to using shorter cranks in the TT position.  With shorter cranks, the athlete can ride a more aggressive position without closing off his or her hip angle at the top of the stroke. 

This year, by switching to shorter cranks, we will attempt to decrease Rinny's back angle while preserving hip angle.  Looks can be deceiving with her current position. She has a 21 degree back angle (most top level pros are around 19-23 degrees), but with her morphology, going lower closes off her hip angle, even when it appears she is very upright.  Rinny will be visting the wind tunnel in a few weeks and we will be able to determine if going lower is actually a faster position for her. 

There is a lot of "cycling tradition" involved when a fitter considers changing something that seems so commonly accepted, such as crank length.  Not all athletes will want, or should move to cranks as short as 165, but should consider going shorter than what they are using.  I plan to introduce more athletes to shorter cranks in 2011 to see the response.  Based on Carfrae's fit data she could use something shorter, but the exact length is to be determined (145-155).  She has too much range of motion at the knee and could benefit from having a more open hip angle.  With the proper documentation and presentation of fit data, Carfrae could become the driver for smaller female athletes to use shorter cranks.