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Not Impressed

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The caption here and article here reports that the guys using math, power, and speed (and variable ambient conditions) have produced a system that tells a user(s?) of said system that using 160 psi rather than 170 psi pressure on this particular indoor track (i.e, an environment pretty damn close to a smooth roller) generates a 75% increase in Crr.

Last Updated on Saturday, 09 March 2013 04:35

A Plot With Many Panels

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A bit confusing, I'll admit...but essentially, the plot shows that, during a european classic, gizmo power doles out bonus watts for a lower average power but constant variability/std deviation (lower right panel).  I still don't understand the value on pinning a single number on the deal.

Training/Racing your bike is pretty basic:


Last Updated on Friday, 08 March 2013 03:51

CFD: Drafting & Interactions

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An interesting article here regarding the folks behind the journal article on drafting I referenced a couple of weeks ago.

While reading the latter bits of that article about the catch-all disclaimer in academia: "future work" (i.e, lateral separation/passing maneuvers/echelons), I reflected upon an experience I had many moons ago where I was contacted by a UCI ProTour rider..

Last Updated on Saturday, 16 February 2013 02:06

tunnel and cfd study of 2up drafting

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Below is a study from 2013 that has cfd and wind tunnel results that shed further light on the aerodynamic interaction between drafting cyclists.  Eyeballing figure 6b indicates that at a separation distance of ~15cm (I'd consider this typical) the lead cyclist can see around a 1-2% reduction in CxA.  A few things here when placing these CFD and wind tunnel result into context:

1) a simplified inviscid analysis yields similar results

2) using 1:10 scale model race car data yields similar results

3) table 5 is something to consider when observing follow car separation distance during TT's:

4) if you are reporting 4x-8x+ what is suggested by these multiple independent lines of inquiry, check your experimental setup, and test again, and again, and again...

5) if you are using a powermeter to quantify this leading cyclist drafting effect, you've got your work cut out for you


Here's the link to the study:




Bad Graphic

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This graphic makes me want to never buy an issue of Inside Triathlon:




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