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.

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:
- Redman
- Desoto American Triple T

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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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

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.

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.

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

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).

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.

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Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T

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.

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 ;-)

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.

Giggling madly for 15 minutes at my last Oly would have had a negative impact on my bike split.

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.

John, thanks for posting this data. Can anyone interpret this data into relative watt or time savings?

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http://www.mountainmettle.com

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...

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.

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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My latest book: "Out of the Melting Pot, Into the Fire" is on sale on Amazon and at other online and local booksellers

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.

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- Matt

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?

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Christopher Kautz
Director of Technology, Product Development, and Education
GURU Sports, a division of Cannondale Sports Unlimited

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!

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2017 Cervelo P2
2017 Cervelo S2
itraininla.com
#itraininla

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!

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Jim Vance
http://TodaysPlan.com.au (Disclosure: I am contracted with Today's Plan)
http://www.CoachVance.com/
Twitter @jimvance

"Yaw" just means there is a slight crosswind. And there almost always is, especially for us middling folk.

A - Yes, and more.

B - Not very. I rode mine at the 91-degree Caliman IM. I didn't even notice it.

C - Quiet going straight, and it whistles in a crosswind. Kinda cool, actually.

So, which ont to get?

[reply]F 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.[/reply]

You are right with the first part. Aerodynamics is a tricky thing...small changes in one part can have huge impact on others... If you change your bodyposition a little, another helmet might (will!) be better. Same goes with wheels and bars and everything. There is just not such thing as a standallone best helmet, wheel, frame... The only serious approach would be: Get your most ergonomic, yet aerodynamic, position on the bike set. THEN go to the tunnel and test various equipment for your own riding position. I realize this is costly and for most (me included) no option. But i think it´s the only way to go if you want optimal results.

That doesn´t mean that almost any aerohelmet is probably better then a standard, just that data from another rider means little to nothing for yourself.

Axel

Thus clearly illustrating the importance of testing at multiple yaw angles...so once again I'm left wondering why they apparently don't normally do this in San Diego?

Ok, I did some age group speed math, I picked two avg speeds for a 40k distance that should be attainable, 24mph and 22 mph. In this model, I used a rolling hills course and Mark the rider made 300 watts avg@ 24mph. Then, I averaged the data using a bell curve I like, with more weight in the 5 - 10 degree crosswind range.

225 watts 300 watts

untaped giro 67:41 60:40

taped Giro 67:05 60:07

L.Gar. tail up 66:23 59:29

L.Gar tail dn 66:23 59:29

Bell/Walmart 67:07 60:09

Rudy Syton w/ flaps 66:50 59:54

Rudy Syto No flaps 66:52 59:55

With the avg. drag used and using the more realistic bell curve for these numbers, tail up or down doesn't matter. Not having many vents exposed [taped over] is important and race wheels are still more important than aero helmets.

I wonder... Did the test rider lower his head for the tail up runs? Simply putting your head down to lift the tail up may lower drag in itself, regardless of the effect the tail has. Or was the rider's head in the same position in both runs, with tail up and tail down?

John thanks again for all this info we all appreciate it.

Could you give me/us a link to some info on correct taping of standard road helmets. I don't have an aero helmet but would like to tape my vents. Do you cover all the vents? Leave any open?

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http://www.mountainmettle.com

Very interesting and informative post there dennis. :)

Anyway, looking at the data for the Rocket vs the other helmets, a weighted average gives a savings of 0.3-0.5lb drag for this guy. It is very interesting that the high yaw tail up is way lower in drag than the tail down. That's very unexpected.

Jens posted some data for his CdA earlier on biketechreview, he said with the Chrono it was 0.2343 and with the Rocket it was .2172. Extrapolating this up to meet John Cobb's data (drag force proportional to CdA) this would indicate the Chrono is somewhere in the 7.7lb average drag range??? That's worse than an Atmos. There must be something else funny going on here...

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"There must be something else funny going on here..."

That is why you cant always take the data from one individual and apply it to another. John measured the data for one particular rider, if anyone of us were going to go into the windtunnel our results could be somewhat different.

My guess is perhaps Jens benefits particularly from aero helmets, it might be due to the fact that his position is most likely more aero than the rider used for this study.

KR

They do, it's just a question of money. When the ProTour teams come, they test at multiple yaws. For the general public, you have the option, but each change requires a few minutes to turn the splitter, which can add up to a several less runs in your alloted time.

Scott

so which helmet?

The other thing is that I used a visor with the Rocket, but not with the Chrono.



- jens

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My latest book: "Out of the Melting Pot, Into the Fire" is on sale on Amazon and at other online and local booksellers

[reply]The other thing is that I used a visor with the Rocket, but not with the Chrono. [/reply]

Ah yes that could certainly make a difference. Although I thought that a previous test on BTR showed little difference with the visor. I'll have to go searching again.

Jens, do you still have your Chrono in size M? I remember measurements you made of the width, but I had a hard time interpreting the 202mm width you stated on BTR. I wasn't sure if you meant the width was measured on *top* of the screw head, or from shell-to-shell. I measured 195mm from shell-shell on my S, and desert dude said his M was also 195mm shell-shell. I get 201.2mm wide at the top of the screw heads.

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Would it still be beneficial to use an aero helmet while sitting up, hands on the hoods, doing a hillclimb? More specifically...

.25 miles @ -1% slope followed by 3.55 miles at 5.7% slope
17.5 mph overall average
bike + rider = 74kgs.
crr = .0042
air density = 1.18

Taped Atmos v. Untaped Atmos v. Rocket?

John.....did either the Rudy or the Rocket have the visor on? Any testing to compare with a visor vs. without?

Thanks.

They do, it's just a question of money. When the ProTour teams come, they test at multiple yaws. For the general public, you have the option, but each change requires a few minutes to turn the splitter
Scott[/reply]
Having experienced the whirlwind of wind tunnel testing three times (pun intended), I certainly understand that, in this setting, time definitely equals money. What I didn't realize was that the splitter platform in San Diego took so long to turn (manually??). At the TAMU tunnel, the balances are on a turntable that can be rotated to a new yaw angle in just seconds.

The Zipp folks did some looking into average wind speed around the country. They concluded that most of our riding involves yaw angles of 10 to 20 degrees. However, I'm not sure if they took ground effects into account. On a day when the weather service reports 10 mph wind, the wind at 3-4' off the ground is probably more like 5-7 mph, which serves to decrease the effective yaw angle.

Look at John's data for the 5-to-10 degree yaw trials. Which helmet has the best set of values in those ranges?

How fast you're riding has pretty big effect on yaw also.

Scott

Having experienced the whirlwind of wind tunnel testing three times (pun intended), I certainly understand that, in this setting, time definitely equals money. What I didn't realize was that the splitter platform in San Diego took so long to turn (manually??). At the TAMU tunnel, the balances are on a turntable that can be rotated to a new yaw angle in just seconds.[/reply]

San Diego's tunnel has an electronic splitter/turntable also. And it is only a matter of seconds to turn it. I'm not sure if you have to get off the splitter to do so or not. I am pretty sure they need to re-zero after turning it though, which means letting the tunnel wind down, then winding it back up for each yaw test (meaning it's at least as time consuming as testing an entirely different position). It would be nice if you didn't have to re-zero and could stay mounted. Then you could just keep the tunnel running and turn through the different yaws...

The behind the saddle bottle thing is interesting, but that's the first real example (besides wheels of course) where I can see the utilty of testing accross a wind yaw range. I still think that if time is limited (which it always is!), a person is likely to get more out of testing lots of things at a single, realistic yaw, than a few things at several yaws (especially since a vast majority of the time you'll see the lower yaws anyway...).

Scott

I do have such an article, and Rudy IS a sponsor. I race in the Rudy helmet because that is what I am required to wear. BUT, I do find the helmet to be very comfortable and faster than my road helmet, although I couldn't give you an exact wattage number. One of these days, I'll do some TT runs with both. I hope to get a chance to do some test runs of it vs. my LG Rocket as well. The Rocket "appears" to be faster than the Rudy, just based off my loose interpretation of my SRM files. But I also would sweat like a banshee (not sure how much banshees actually sweat) in the LG (it is great in the winter, though), and I don't in the Rudy. I think that is definitely a factor given that we run after biking. Were this a bike-only sport, temperature and fluid management would be a non-issue. But it isn't.

The point of my article on the Timex site was more to encourage people to get *an* aerohelmet. The Rudy is a nice compromise for people that don't want the full dome covering. I have a friend who races in a Rocket, and he definitely notices extra strain in his neck. Maybe a bit of extra weight, but also with that big tail (which is what makes it fast) crosswinds are going to affect you more. So the Rudy is a nice balance of comfort (weight and heat) and aerodynamics. But if you want to go as fast as possible, I will readily admit that there are helmets that are going to be faster.

Even the folks at Rudy know it is not the fastest possible design. Most of the Rudy sponsored teams raced in the helmet with the carbon fairing shell in the TdF & Giro. There are pics of it somewhere. That shell will be available next spring ('07), so similar to the visor and earpieces, you can make your helmet more aero (and a bit hotter) should you choose to.

I'd love to have some real tunnel data to quote, but I don't. If I get around to doing some tests with my SRM, I'll post those, as flawed as they may be.

EDIT: I replied before seeing John's data. Certainly not suprising. I'd still like to do some runs on my own, just to see what I get out on the road, which of course will be less precise, but also unique to my position.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Yup. A 5-degree yaw for you is 10 degrees for me. ;-)

I cant find a pic of the new giro aero helmet that will be coming out...anybody see it yet? I heard it is a bit different than what we have seen in the tours that some teams are wearing!

Bottom of the page:
http://www.cyclingnews.com/road/2006/tour06/tech/?id=/tech/2006/features/tour_giro_ionos

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

thanks Rapp. Looks very nice! I cant wait to get one!