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Aerodynamic Testing of Aero Helmets?
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Can anyone cite any studies done on the aerodynamic advantages between different aero helmets? Someone told me a certain company's aero helmet provided little to no aerodynamic benefit. (I would rather not mention the name, because it would only perpuate a rumor at this point). I have done some Google searching for tests done, but have found nothing. I'm interested in seeing what helmets might be better than others, or if there is any difference at all.

Thanks in advance.

Jim Vance
http://www.CoachVance.com/
http://www.FormulaEndurance.org/
Twitter @jimvance
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Re: Aerodynamic Testing of Aero Helmets? [JimVance] [ In reply to ]
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Let me say what I've heard to spur things the. Rudy is supposedly no better than a taped helmet.

However, if I were to pick any aero helmet for my needs right now and in the future, I'd go Rudy. It apears to have a small frontal area, the tail that is there stays fairly low, and the earwings may or may not increase effectiveness.
Currently I have a LG prologue and it took a lot of time working with the pads and straps to get it into a compromise between aero, comfort and safety. I would be highly surprised to find out it is faster than a Rudy but its way more comfortable.
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Re: Aerodynamic Testing of Aero Helmets? [Runless] [ In reply to ]
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Rudy is supposedly no better than a taped helmet.


If a taped helmet is a significant improvement then the Rudy seems like a pretty good deal long term. Granted you could continually tape and retape a road helmet, but considering how much people spend on aero wheels a little for a Rudy seems cheap to avoid the taping.

I guess that just opens the new question of how beneficial is taping a helmet.


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Justin in Austin, get it? :)

Cool races:
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Re: Aerodynamic Testing of Aero Helmets? [JimVance] [ In reply to ]
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Someone posted some comments from MIT about wind tunnel testing. I guess the jist of it was that an aero helmet is more advantageous than aero wheels. Hence all the talk about aero helmets.


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Re: Aerodynamic Testing of Aero Helmets? [Runless] [ In reply to ]
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Not knowing any better I have to wonder why Michellie Jones, Chris McCormack, and Heather Fuhr would use the Syton helmet, knowing they have all been in the San Diego tunnel recently, unless the helmet was effective. Could Rudy's sponsorship really be so great they would ignore the data?


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Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T
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Re: Aerodynamic Testing of Aero Helmets? [Runless] [ In reply to ]
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However, if I were to pick any aero helmet for my needs right now and in the future, I'd go Rudy. It apears to have....


But, isn't the whole point of Jim's post, "Anybody got data?" Without data, "appears to have..." is just guessing.

I know of one guy who tested an LG Rocket vs. LG Chrono and the Rocket was materially faster. Lots of people have tested Rocket vs. regular helmet and the Rocket wins every time I'm aware of. I can't think of a specific reference to the Rudy. However, if we resort to the "appears..." sort of analysis, it would appear to me that I'd rather have a Rocket (or Giro or Bell) than a Rudy.

Jim, head over to Biketechreview.com and post your question there. Somebody might have a specific reference for you.
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Re: Aerodynamic Testing of Aero Helmets? [Justin in OK] [ In reply to ]
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Could Rudy's sponsorship really be so great they would ignore the data?


Yes.

Who says they even took other helmets into the tunnel?

I'm not writing this to say that the Rudy is slow -- just that people shouldn't take too much out of a pro's equipment choices. Some of those folks ride tires that are proven -- proven -- to be slower than other tires. Same with wheels, frames and damned near anything else.
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Re: Aerodynamic Testing of Aero Helmets? [Justin in OK] [ In reply to ]
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I have read a study done by Kaï Hundertmarck (former pro-cyclist and usual top bike times on IM) related in the german triathlon magazine. He was riding on a track at 30mph (controled by SRM) and using different wheels, helmets, an frame (Soloïst and P3). The only things I remember is that the gain of the aero helmet was 6W on a total of around 350 watt. Also the most efficiently wheels combination was a pair of Xentis, before a Zipp 404 + disc. It can be explain by the fact that on a track there is no wind, just a only frontal resistance ... the natural incident wind would have shown the disc superiority.
HTH

Nick
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Re: Aerodynamic Testing of Aero Helmets? [JimVance] [ In reply to ]
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Can anyone cite any studies done on the aerodynamic advantages between different aero helmets?
Somewhere I should still have all the helmet test results from Project 96. However, they are >10 y old now, and none of the helmets that were tested are still being made (although you can occassionally find one on, e.g., eBay, and they do remain legal, at least for USCF racing). So, these data are probably not of much use to you, except to illustrate that the right aero helmet can reduce drag significantly (especially the long-tailed ones).
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Re: Aerodynamic Testing of Aero Helmets? [Ashburn] [ In reply to ]
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In Reply To:

Who says they even took other helmets into the tunnel?

I'm not writing this to say that the Rudy is slow -- just that people shouldn't take too much out of a pro's equipment choices. Some of those folks ride tires that are proven -- proven -- to be slower than other tires. Same with wheels, frames and damned near anything else.
You are right and I know/knew it. In the absence of any real data I just have to hope that those 3 people who went to the tunnel and wear the same aero helmet tested said helmet for it's aerodynamic properties. Seems like not much of a stretch, but as you point out, Pro's make stranger choices. Until there is real data for the Syton (that is available to me) that is all I have to go on. Not very scientific, but a reasonable rationalization for the time being.


----------------------------------
Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T
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Re: Aerodynamic Testing of Aero Helmets? [Justin in OK] [ In reply to ]
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Until there is real data for the Syton (that is available to me) that is all I have to go on. Not very scientific, but a reasonable rationalization for the time being.


I'm sure there is data for the Syton. I've seen tunnel pics of riders with and without one, so I assume they tested the helmet versus a regular lid (which is what the pictures show). I just wouldn't assume that they tested a series of aero helmets from different manufacturers.

I have no doubts that the Syton is faster than a regular bike helmet.
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Re: Aerodynamic Testing of Aero Helmets? [Runless] [ In reply to ]
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I think Jordan Rapp has an article on the Timex site about aero helmets and specifically mentions the Rudy (presumably a sponsor?).

I am sure they are faster but I just can't convice myself to get one. I am afraid some old school dude will pass me and laugh. That is what I am going to do if I pass someone with an aero helmet ;-)
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Re: Aerodynamic Testing of Aero Helmets? [TriMike] [ In reply to ]
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That is what I am going to do if I pass someone with an aero helmet ;-)


Was that you laughing at me a while back? ;-)

Remember, the point of all this aero gear and positioning stuff is not to compare your new result to the guy next to you, it's to compare it to how you would have done without it.

In my case, getting my bike fit sorted out, using race wheels (808 front and cover on the rear), and an aero helmet took me from needing 240 watts to go 23 mph to only needing about 205-210. Sure, plenty of people can still beat me, but I'm beating a lot more of them than I used to.

In the last two years at Oceanside, I had faster bike splits than guys who I know for a fact are phenomenally stronger cyclists than me.
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Re: Aerodynamic Testing of Aero Helmets? [TriMike] [ In reply to ]
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I am afraid some old school dude will pass me and laugh. That is what I am going to do if I pass someone with an aero helmet ;-)


Giggling madly for 15 minutes at my last Oly would have had a negative impact on my bike split.
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Re: Aerodynamic Testing of Aero Helmets? [JimVance] [ In reply to ]
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First disclaimer, I'm not doing helmets or selling helmets for anybody. I just have that problem of curiosity and because I still position a lot of racers I needed to know some facts. I went to the A&M tunnel on August 1st, got a volunteer to test some things and here are the results. Note**** helmets test a little different on different riders because of back shapes and pelvis rotation. These results are for this rider but I think they generally would have the same results.

The bike was a New Look TT frame, FSA aerobars, 50mm Blackwell wheels front and rear. Wheels were spinning, rider was 6'2" - 170 lbs, multi-time Ironman racer, Mark Miller, owns a bike shop in lafayette, La. He supplied most of the helmets, Mark has been to the tunnel with me many times and knows how to sit accurately and repeatable.

First run for base line in his current race position with an untapped Giro Atmos helmet, rear water bottle cages.

Yaw 0 2.5 5 10 15 20

untaped Atmos @ race angle 7.64 7.75 7.41 7.47 7.56 8.33

taped vents Atmos @ same race angle 7.47 7.12 7.31 7.10 7.73 8.16

L. Gar. rocket, tail up 6.97 7.24 7.21 7.26 7.00 7.16

L. Gar. Rocket tail dn 7.24 6.95 7.03 7.03 7.28 7.73

Bell/ Walmart Impulse, taped 7.27 7.63 7.36 7.27 7.38 7.98

Rudy Syton w/flaps 7.31 7.50 7.29 7.07 7.31 7.74

Rudy Syton No flaps 7.24 7.34 7.33 7.18 7.28 7.81

For me, same setup as test #2 - taped vents, Atmos - Landis High hands replicated pretty close: 7.89 7.73 7.62 7.53 7.58 7.97

I'll stick with lower hands for a little longer.

Andrew Coggan can figure the speed/time for you for fun.

New Blog - http://www.johncobbresearch.com
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Re: Aerodynamic Testing of Aero Helmets? [John Cobb] [ In reply to ]
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John, thanks for posting this data. Can anyone interpret this data into relative watt or time savings?



QT2 Systems

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Re: Aerodynamic Testing of Aero Helmets? [John Cobb] [ In reply to ]
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John...did I read in this data that the Rocket Tail up is quicker than the Rocket Tail down? Is this like all those short airfoils that stick upright out of the fuselage of many commercial and fighter aircraft to keep the airflow laminar?
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Re: Aerodynamic Testing of Aero Helmets? [devashish paul] [ In reply to ]
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John...did I read in this data that the Rocket Tail up is quicker than the Rocket Tail down? Is this like all those short airfoils that stick upright out of the fuselage of many commercial and fighter aircraft to keep the airflow laminar?


Notice, that was only @ zero yaw, or 15-20 degrees...almost no one is ever @ zero, and I don't know about you, but some basic trig means that at 20 degrees of yaw, I'm probably not riding my TT bike....

Also, factor in the Cda of actually moving the helmet up and down (since tail-up means you can't see anything), and tail-down seems like the winner.

I've seen tunnel video on Willet's site that show the effects of moving the helmet around, and even if "tail up" were faster, the act of getting it there is pretty messy from an aero standpoint.

Those numbers seem to make a good arguement for the Rocket...
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Re: Aerodynamic Testing of Aero Helmets? [devashish paul] [ In reply to ]
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I think that when the tail was up it helped mask the rear water bottles on this rider by shooting the air past the rear bottles before it reattached. If you notice, most of the numbers shot up from 20* and on but I didn't list the further out numbers. I believe this was from the rear bottles in most cases adding a lot of surface area suddenly.

New Blog - http://www.johncobbresearch.com
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Re: Aerodynamic Testing of Aero Helmets? [Spindogg] [ In reply to ]
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In Reply To:
John, thanks for posting this data. Can anyone interpret this data into relative watt or time savings?


It looks like @ 28mph for 40K, the saving of the Rocket vs. regular/untaped helmet, at 5-10 mph variable wind, 20 degree angle, comes to almost a 2 minute savings...someone feel free to check my calcs on analyticcycling.com, but that seems about right to me.



http://www.analyticcycling.com/...WindCourse_Page.html
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Re: Aerodynamic Testing of Aero Helmets? [roady] [ In reply to ]
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In Reply To:
In Reply To:
John, thanks for posting this data. Can anyone interpret this data into relative watt or time savings?


It looks like @ 28mph for 40K, the saving of the Rocket vs. regular/untaped helmet, at 5-10 mph variable wind, 20 degree angle, comes to almost a 2 minute savings...someone feel free to check my calcs on analyticcycling.com, but that seems about right to me.



http://www.analyticcycling.com/...WindCourse_Page.html


That's in the ballpark of what I got when I tested it. Though I didn't do all the yaw angles.



-- jens
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Re: Aerodynamic Testing of Aero Helmets? [roady] [ In reply to ]
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It would be interesting to see how the new(sort of) Giro Advantage 2 tests. I was told by the rep for our lBS that is is due out soon so it will be another one to throw into the mix.

- Matt

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Re: Aerodynamic Testing of Aero Helmets? [John Cobb] [ In reply to ]
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Assuming tail up equals head down, wouldn't the lower drag numbers most likely result from the significantly lower FA an athlete has with the head dropped?


Christopher Kautz
Director of Technology, Product Development, and Education
GURU Sports, a division of Cannondale Sports Unlimited
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Re: Aerodynamic Testing of Aero Helmets? [John Cobb] [ In reply to ]
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Ok I am just an air freight sales guy who is ready to buy one the these things because they look cool, and freight is boring but pays the bills.

But what in the H. E. double hockey sticks does this mean? and how often do we ride with a yaw rate??? I know we think we are fast but we are not airplanes.

I know for pros like Jim and the tour guys this stuff means something because they racing for money, but does it mean to us guys who are "playing" on the weekend.

A) Will it make me :30 faster over an Olympic at 21 ave
B) How hot do they get?
C) Do you get wind noise on LG Rocket?

Seriously though when you front of pack 40 to 45 ers go by me just say nice helmet and cool bike! OH wait they passed me in the water!

2015 Felt B12
2009 Ridley Noah
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Re: Aerodynamic Testing of Aero Helmets? [roady] [ In reply to ]
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In Reply To:
In Reply To:
John, thanks for posting this data. Can anyone interpret this data into relative watt or time savings?


It looks like @ 28mph for 40K, the saving of the Rocket vs. regular/untaped helmet, at 5-10 mph variable wind, 20 degree angle, comes to almost a 2 minute savings...someone feel free to check my calcs on analyticcycling.com, but that seems about right to me.



http://www.analyticcycling.com/...WindCourse_Page.html


John, thanks for posting that! It's exactly what I'm looking for. Now I just need to learn how to interpret the data accurately. A few questions I am hoping someone can answer for me: (Sorry if they sound a little basic)

1. What does "yaw" stand for or mean exactly?

2. Wouldn't this statement above only be true if a course is straight out, point to point? Would it still have the same effect if it was out and back? Or would the angle of the wind not change, just be from a different side? And what if the course is a loop? Do tailwinds affect it?

3. What kind of things can we attribute to the Rudy Helmet differences with the side flaps on vs. off?

Thanks again, that's awesome data!

Jim Vance
http://www.CoachVance.com/
http://www.FormulaEndurance.org/
Twitter @jimvance
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