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Home Performance Demand

Flow Stagnation, Ideal Fluids, and You

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Almost two years ago during the summer of 2004, I began fiddling with SRM power meter based field tests in an effort to see how this methodology might be used to evaluate the aerodynamic characteristics of different cycling positions.  I was never really satisfied with the results I obtained along the way – the downfall, for me, of this testing approach was too much variability (e.g. – even the slightest breeze effects results) and therefore, too much time involved to generate meaningful results.  In an effort to reduce and/or compensate for ambient wind conditions, I attempted to measure wind speed while conducting my field test trials.  The wind speed measurement didn’t seem to help things much; however, along the way I was successful in demonstrating that the flow in front of a cyclist stagnates.


Last Updated on Monday, 15 March 2010 00:59

Faster is Faster

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There are some fitters and manufacturers that would have us believe that a more forward saddle position relative to the bottom bracket, or a “steep” seat tube angle on your TT/Triathlon bike is the better and faster decision.  Put more simply, their argument is “forward is faster”.  Well, I’m all for simplicity, so I reckon if I had to boil down my thoughts on the TT/Tri bike positioning topic to a catchy little phrase, it’d be: “faster is faster.”

Last Updated on Thursday, 03 July 2014 02:44

The Pareto Principle and TT Aerodynamics

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Words and images by:  Kraig Willett

(note from the author: this was originally written in late 2004 and posted on the BTR Insiders page. Since the original publishing of this article, the author and the BTR crew have worked with over 100 athletes at - the author didn't edit the content of this article based on those experiences.)

Around the turn of the 19th century, a clever Italian economist, William Pareto, made the observation that 80% of his country’s wealth was accounted for by 20% of the population.  This 80/20 rule, or the Pareto Principle, concisely states that there exists an uneven relationship between outputs and inputs. 

Last Updated on Sunday, 27 December 2009 17:34

The Rule of the Thumb

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I was recently accused of having too much time on my hands.  This brutally honest feedback was dished out in response to a little study I recently completed which dealt with, ironically, hand position during cycling time trials.  In my defense, I’d just like to say that by using some simple digital image processing techniques, it doesn’t take very long for armchair scientists like me to conduct a “poor man’s” virtual wind tunnel test by measuring frontal area. 

Last Updated on Monday, 28 December 2009 00:55

Time-Trial Equipment Choice

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An in depth analysis of Chris Horner’s 2002 Redlands Prologue TT victory

words and images by Kraig Willett

(4/10/2005: A note from the author:  The mathematical modeling methods in this article have been dramatically improved in the days since this article first appeared in 2002.  With the better models, the absolute numbers may have changed for this analysis, but the overall message remains the same...)

One of the favorite questions that I like to ask any bicycle company representative I meet is: “Are the performance benefits of the widget you sell, significant?”  It is a great question because the answer one receives tells a lot about the person you are talking to.  If a one sided answer proclaiming that the widget in question is the best thing since sliced bread is received, it can be assumed that the “dark side” of the force (marketing/sales hype) has overtaken this particular person.  However, if a well-balanced answer stating that significance is a difficult subject open to many interpretations and perceptions, it can be assured that the person is firmly grounded in reality.  I would much rather chat with the person who holds the latter opinion of “significance”.

Last Updated on Friday, 25 March 2011 03:28