Monday, March 19, 2012

Pro Bike Fit

Compilation of fit information from published data dating back to 2006 from various online publications (click to enlarge):


Here is the latest chart; now based on a sample size of 140 points for saddle height and 138 points for reach.  Saddle Height is as measured along the seat tube from the center of the bottom bracket to the top of the saddle, and Reach is measured in a direct line from the saddle tip to the center of the handlebars.  The equations shown are for the best fit line, and the dashed lines represent plus/minus 3 cm. R-squared is the coefficient of determination as calculated by Excel. "RS" is the Spearman's rank correlation coefficient.


6 comments:

  1. Great work, can you clarify the stack and reach, are they horizontal/vertical distances or actual distances?

    Have you performed a spearman rank test or any other to clarify the 'goodness' of the correlation?

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  2. My understanding is that "reach" is measured directly from the saddle tip to the handlebar (i.e., along the hypotenuse of the imaginary triangle), and "stack" is measured directly from the center of fork dropout to the top of the handlebar (again, along the hypotenuse).

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  3. Also, I haven't done anything to test the quality of the best-fit lines shown; they are simply what are given by Excel. I am thinking about doing a little more heavy-duty statistical analyses this coming weekend if I can get around to it, including Monte Carlo analyses for some of the measurements with a good sample size to see if I can clear things up a little bit.

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  4. Saddle height from the pedal axle I assume? or from BB?

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  5. It should be from center of BB to top of saddle measured along the seat tube.

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  6. The chart is up to date as of March 28, 2013.

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