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The great helmet wars 2008
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Andrew Coggan
Aug 25, 08 11:42
Post #1 of 134 (3491 views)
The great helmet wars 2008
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Solid blue and pink lines represent computed values based on analysis of multiple test runs (n=7 west- and east-bound pairs at speeds ranging from ~6 to ~14 m/s) made on separate days (for the two helmets) through the local "natural wind tunnel".
Solid blue symbols represent the results of three west-bound and two east-bound runs made while wearing the Louis Garneau on the same day that I tested the Spiuk. (A car passed me during one east-bound run, so I had to toss out those data.)
Solid yellow symbols represent two runs (one in each direction) made while wearing a Giro Advantage 2 on the day that I tested the Louis Garneau helmet.
All data have been adjusted to account for differences in air density, mass, etc.
The Louis Garneau and Giro helmets are size M, whereas the Spiuk is one-size-fits-all. Tape was used to seal the vents of all three helmets.
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by Andrew Coggan on Aug 25, 08 11:55)
Trianthes
Aug 25, 08 11:45
Post #2 of 134 (3458 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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Sweet. What does it mean?
Andrew Coggan
Aug 25, 08 11:49
Post #3 of 134 (3411 views)
Re: The great helmet wars 2008 [Trianthes]
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Sweet. What does it mean?
Isn't it obvious?
JasoninHalifax
Aug 25, 08 11:50
Post #4 of 134 (3401 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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statistically significant differences??
____________________________________
Fishtwitch clique (ex-butterflyer)
"Cats like Ham" - Tom D.
Andrew Coggan
Aug 25, 08 11:54
Post #5 of 134 (3380 views)
Re: The great helmet wars 2008 [JasoninHalifax]
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statistically significant differences??
That depends on the alpha you choose, as well as whether you do a one-tailed or a two-tailed test.
EDIT: As illustrated by the solid symbols, the power required to travel a specific speed is generally reproducible to w/in ~1% in the absence of wind (yellow symbols), or even in the presence of wind if you consider its direction (blue symbols) (I don't know what's up w/ that one outlier).
(This post was
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Trianthes
Aug 25, 08 11:56
Post #6 of 134 (3358 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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I should use the Rocket b/c it is cheaper and no appreciable difference exists with the others tests? I thought the advantage to the Spiuk was that if was solid, in that, if you didn't have it almost touching your back it was no big deal . . . not the case with the Rocket.
ksull
Aug 25, 08 11:57
Post #7 of 134 (3345 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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Cool! what are thoughts on the LAS TT helmet?
Kerry Sullivan
USAT,USACII, CSCS, NLP practitioner
http://www.BlazingTriSpeed.com
JasoninHalifax
Aug 25, 08 11:59
Post #8 of 134 (3333 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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But you are the one with the data. What do YOU say?
____________________________________
Fishtwitch clique (ex-butterflyer)
"Cats like Ham" - Tom D.
ATX TRIHEAD
Aug 25, 08 12:04
Post #9 of 134 (3298 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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Why seal the vents? I thought that is what was creating drag in regular helments...
Small words please
GregX
Aug 25, 08 12:07
Post #10 of 134 (3276 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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interesting.
but a lot more interesting would the comparison of this data via a similar test with a "bare-headed" rider.
and comparison of this data to a similar test with a "standard helmet" (like a giro pneumo) rider.
any chance you could do that?
"Half of what we taught you is wrong. Unfortunately, we do not know which half."
-- Dean and cardiologist C. S. Burwell to a Harvard Med School graduating class.
Where would
you
want to swim ?
Andrew Coggan
Aug 25, 08 12:22
Post #11 of 134 (3189 views)
Re: The great helmet wars 2008 [JasoninHalifax]
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What do YOU say?
I'm glad that we own a Rocket?
Andrew Coggan
Aug 25, 08 12:31
Post #12 of 134 (3129 views)
Re: The great helmet wars 2008 [GregX]
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a lot more interesting would the comparison of this data via a similar test with a "bare-headed" rider.
and comparison of this data to a similar test with a "standard helmet" (like a giro pneumo) rider.
any chance you could do that?
Not really, as I would never ride w/o a helmet, or race a TT w/o an aero helmet. IOW, while the results might be interesting, they don't have much practical value (for me, anyway).
Andrew Coggan
Aug 25, 08 12:32
Post #13 of 134 (3122 views)
Re: The great helmet wars 2008 [ATX TRIHEAD]
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Why seal the vents? I thought that is what was creating drag in regular helments...
Small words please
Vents = turbulence = drag.
trvfsub2
Aug 25, 08 12:33
Post #14 of 134 (3110 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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So the Rocket is the best? Or the best for you?
tfun~
ATX TRIHEAD
Aug 25, 08 12:34
Post #15 of 134 (3100 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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I understand that but why test them differently than they are worn?
Andrew Coggan
Aug 25, 08 12:35
Post #16 of 134 (3081 views)
Re: The great helmet wars 2008 [ksull]
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what are thoughts on the LAS TT helmet?
This one?
http://www.glorycycles.com/lascrtitrhe.html
I'm far from an expert on helmet aerodynamics, but my eyes don't like the way the helmet curves so quickly down to the tail.
That said, if anybody in St. Louis wants to loan me one, I
might
be able to find time to test it.
Andrew Coggan
Aug 25, 08 12:36
Post #17 of 134 (3069 views)
Re: The great helmet wars 2008 [ATX TRIHEAD]
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I understand that but why test them differently than they are worn?
I tested them as I would wear them.
Andrew Coggan
Aug 25, 08 12:37
Post #18 of 134 (3059 views)
Re: The great helmet wars 2008 [trvfsub2]
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So the Rocket is the best? Or the best for you?
It is the best (so far) for me.
bpq
Aug 25, 08 12:37
Post #19 of 134 (3056 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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Knowing your position, and given that they're all good helmets, I am not surprised that they posted relatively similar numbers with taped vents. Or that the longer, smoother shape of the Rocket bore out the best, but - do you race w/ taped Vents?
It would seem that anything over 20 min and 70 degrees, and you would start to see negative effects from the lack of ventilation. I don't know if I'd lose power, but I'd probably run into a tree after about 3 miles due to all the sweat in my eyes.
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Vir prudens non contra ventum mingit - A wise man does not urinate against the wind.
ATX TRIHEAD
Aug 25, 08 12:38
Post #20 of 134 (3046 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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LOL, I don't see many people taping up the vents. It seems like the more and more areo lids come out the more vents they have. Just from observation. I kind of thought it defeated the purpose.
Andrew Coggan
Aug 25, 08 12:42
Post #21 of 134 (3014 views)
Re: The great helmet wars 2008 [bpq]
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Knowing your position, and given that they're all good helmets, I am not surprised that they posted relatively similar numbers
I guess that depends on how you define "relatively similar". For me, choosing the Giro over the Louis Garneau would cost me ~1 s/km.
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with taped vents. Or that the longer, smoother shape of the Rocket bore out the best
The Spiuk is actually just a smidgen longer than the Rocket.
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, but - do you race w/ taped Vents?
Yes.
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It would seem that anything over 20 min and 70 degrees, and you would start to see negative effects from the lack of ventilation.
I don't have that problem.
(This post was
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by Andrew Coggan on Aug 25, 08 12:57)
ksull
Aug 25, 08 12:43
Post #22 of 134 (3004 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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yea thats the LAS helmet I was thinking of.
Kerry Sullivan
USAT,USACII, CSCS, NLP practitioner
http://www.BlazingTriSpeed.com
jeffp
Aug 25, 08 12:46
Post #23 of 134 (2988 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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I, on the other hand, can't see where I am going after about 10 minutes no matter how many vents a helmet has. I just kind of ride through the blurr. Part of the problem with hitting all those unnoticed potholes, I guess. :)
Tom A.
Aug 25, 08 13:04
Post #24 of 134 (2902 views)
Re: The great helmet wars 2008 [Andrew Coggan]
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It would seem that anything over 20 min and 70 degrees, and you would start to see negative effects from the lack of ventilation.
I don't have that problem.
Me neither...and I even have a visor on mine too :-)
Have you thought about trying the LG with a visor in place? My own testing showed it to be possibly
slightly
faster with it in place (in any case, not slower)...but the reduction in wind noise alone was worth it.
Andrew Coggan
Aug 25, 08 13:07
Post #25 of 134 (2882 views)
Re: The great helmet wars 2008 [Tom A.]
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Have you thought about trying the LG with a visor in place?
Thought about it, but there are some other things I want to test first.
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