Monday, March 19, 2012

Pro Bike Fit

Last update: January 23, 2017

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Before you look at the information below, here are some thoughts/comments:

- There are quite a few sources of error in data like this, such as measurement errors (measurements are made by different journalists at different times), discrepancies in listed height of riders versus their actual heights, the impact on saddle length on the "reach" measurement (for example, the popular Fizik Arione saddle is 2 cm longer than most other saddles). Also, different handlebars have different reaches, and different shift levers have different hood lengths (Campy vs. Shimano vs. Sram), which have implications on reach that are not quantified here.
- Professional cyclists may not be reflective of the average population. For example, there may be inherent physical traits that pros possess (which may have helped them to become a pro in the first place) that an average cyclist does not.
- Professional cyclists on average tend to have slightly higher saddle positions (better hamstring flexibility), and longer reach / more saddle-to-bar drop (better core strength and for aerodynamic positioning) compared to an average cyclist.

With those in mind, these charts should be considered for informational purposes only. For example, as a 6' (183 cm) tall male with slightly longer legs than average, my saddle height is 77 cm (as compared to 77.7 cm indicated by the first chart), my reach is 57 cm (as compared to 59.4 cm indicated by the first chart), my saddle setback is 8 cm, and my saddle-to-bar drop is 7.5 cm.

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Below is a compilation of pro cyclist fit information from published data dating back to 2006 from various online publications (click to enlarge):


"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 chart is based on a sample size of 199 data points. The equations shown are for the linear best fit line, and the dashed lines represent plus/minus 3 cm, which bounds the upper and lower bounds of the data fairly well. R-squared is the coefficient of determination as calculated by Excel.

Below is the same data, but instead of individual data points, a "three-point running average" was taken:



In addition to saddle height and reach, some of the published data also included information on saddle setback (from the center of BB to the tip of the saddle) and saddle to handlebar drop; see below. It is interesting to note that while saddle to handlebar drop shows an overall increasing trend with increasing height, the average value is 11.7 cm with a relatively low standard deviation of 2.2 cm (which means that 68.3% of riders fall within a range of 10.5 to 13.9 cm).

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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