First of all, thank you to Kiley, Brian, Heath, David and everyone else who contributed to this ambitious project. Having been to the wind tunnel a couple times, I have some appreciation for the challenges they must have faced. It was also great to see involvement by Jimmy from Ventum and Dan from PremierBike, who were taking a risk by facilitating this independent testing.
Like others, I'm struck by how close together all the bikes are. As the report points out, four of the six bikes had essentially indistinguishable drag when accounting for error. I agree that, given the stated uncertainty, it makes more sense to view the results as two performance groups rather than a definitive ranking. Unfortunately, this may be difficult to grasp for those who haven't studied statistics. Kudos to the authors for including an error analysis (albeit limited, as they pointed out), which is too often overlooked in whitepapers.
In general, the test protocol looks sound, given the limitations of the testing (just 4 hours). My biggest reservation is that the
Ventum was the only bike tested without front hydration. My own testing at the FASTER wind tunnel with Ventum showed a significant decrease in drag when adding front hydration. This is consistent with nearly all the other data I've seen; well placed front hydration (whether it's a standard, round BTA bottle or other system) tends to lower drag. The Ventum was likely penalized by testing without front hydration.
An alternate test protocol would have been to optimize each bike setup rather then attempt to standardize them. This would include finding the fastest position, helmet, clothing, wheels, fluid and storage options for each bike. This would have been prohibitively time consuming (Jimmy estimated ~6 hours per bike!), but more realistic and definitive. Just one example is that the Diamondback was tested without its integrated storage which would usually be in place, putting it at a disadvantage.
Slowman wrote:
there is nothing wrong with the ventum. this was like an 800 meter run, with 1st place clocking 1:42.68 and last place clocking 1:43.03. there were no dogs in this test. the best bike and the worst were separated by where you choose to place your hydration.
to wit, i *think* all the bikes had an aerobar mounted bottle except the ventum, which has on-board storage and much more than 1 bottle. therefore, if you placed 2 bottles on any of these bikes perhaps the ventum wins. now, the flip side of this, if you also placed a handlebar bottle on the ventum, this makes the ventum test worse (one assumes).
so, the ventum is either the best bike, or the worst, or somewhere in between, depending on storage and hydration preferences. this tells you how close all these bikes are.
(i'm sure someone will disabuse me of any error in my analysis.)
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