In Reply To:
the drag/speed numbers imply a Cda around 0.245-0.255. For a small guy like Levi that's surprisingly large. Perhaps he ought to hire Jens/Tom/AC as consultants :-)
If the numbers have been 'adjusted' to protect his true data that should have been stated ...
Something does not quite compute ... else my spreadsheet is just way off.
I think you have hit it right on the head.
Back in March, Trek got Pezcyclingnews to write an article on the February tunnel testing with Basso on a Equinox TTX and a P3C and the difference was "within the margin of error". According to several people who were at the tunnel, it took 2 days of changing Basso's position before they could get his drag as low as on the P3C in his original position, so the TTX was only as fast as the P3C because they improved his position, not because the bikes were equally fast. According to my sources, there was a significant difference in favor of the P3C when the rider positions and the parts used were the same.
Now they show tunnel tests with the same February date, but all of a sudden the rider is Levi. Yet the CdA of Levi is supposedly the same as the CdA of Basso, and way above where Levi tested previously. Could it be that they would rather not use Basso's name anymore, and Levi was never tested on a P3C? Or do they really buy a P3C for every Disco rider to test him in the tunnel on our bikes? Or did they squeeze Levi on Basso's P3C, which would obviously be way too big for him? I can't make sense out of it.
And to top it all off, the already unsustainable "the bikes are the same" from the pez article has turned into a significant gap in favor of the TTX on bikeradar, even though they are supposedly comparing the same frames? The SSL name of the bikeradar makes no difference, that just changes the weight, the shape is the same (especially since this test is from February when there wasn't even an SSL to begin with). In the most benevolent case, it shows that tests with a rider on the bike are completely unreliable and unrepeatable (we have done tons of tests with riders on the bike, and you just cannot get riders to keep the same position when switching bikes - which is why we use a test dummy, see our latest eNews (
https://customercare.cervelo.com/esupport/enews.aspx). In a less benevolent way, maybe the inaccuracy of the test was used to skew the results in favor of the one paying for the test.
Gerard Vroomen
3T.bike OPEN cycle