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Welcome to BTR!

Triathlon Pacing

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The insights surrounding average power contained in this plot I created about a decade ago are still important when it comes to pacing the last two events of an iron distance triathlon:

triathlon pacing



The Importance of Tire Selection

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All samples described below were tested at the Oran W. Nicks low speed wind tunnel at Texas A&M University using dedicated cycling fixtures in January of 2003.  Data is presented as axial force (which is equivalent to drag at 0 degree beta/yaw) at 30 mph.  Relative ordering will be the same at lower speeds, but the magnitudes will be decreased.

Last Updated on Saturday, 26 October 2013 01:46

build your own wind angle probe

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Here is a parts list spreadsheet for the wind angle sensor I cobbled together a year and a half ago.

If you are interested in collaborating with me to improve the prototype design/manufacture, send me a note:

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average tour stage power and speed

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I spent <5 minutes on google this evening and found these two nuggets that might help the scientists @mitaerobike, @chrisyuinc, and also @jim_gourley / @rappstar over on twitter do some helmet claim math...

5 hr flat stage power and speed:

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4


5 hr climbing stage power and speed:

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4


...and new information in the mix is that the Specialized crew is now claiming only 20W over their road helmet at 30 mph while being tested on a mannequin in isolation in a wind tunnel (as I understand things):


based on the new bits of information above, what are your estimates for watt savings during a 5hr tour stage?

***Incentive alert***

free, single BTR report for the most clever interaction on the twitter exchange here:

or the facebook post here:


good luck!




Last Updated on Saturday, 05 October 2013 17:33

Specialized Evade Aero Helmet Claims

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Awhile ago Specialized released this video during the launch of the s-works evade road helmet:

At about the 1:35 mark a claim is made that the helmet would save 400kj during a 5-hour stage of the tour de france. Sounds like a lot, doesn't it?!?  Let's take a closer look at this claim for fun.

Last Updated on Sunday, 29 September 2013 23:19
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