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Welcome to BTR!

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:

This e-mail address is being protected from spambots. You need JavaScript enabled to view it



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

Training "Load": Raise and Fill

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When it comes to quantifying overall training "load" it really doesn't get any better than:

1) monitoring time spent going hard in significant/meaningful chunks (i.e - if it feels hard, then it is hard.  so, yeah, log it as such...)

2) monitoring KJ's of external work (yeah, strava gets it good enough for solo rides)


Last Updated on Saturday, 23 March 2013 20:17
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