Snapshot: New Stubby Aero Helmet vs. Long Tail Aero Helmet.

my thought (albeit I can't back it up with data...or much at least) is that

*if*

you find an aero helmet that works well with your "profile" (that is, when you are in aero position it is a clean line, unlike the rider in the picture...)

*and*

considering you keep that position, as opposed to spending the day with the tail in the air looking down

then a tail will have real benefits. If not, then the stubby tail is a *safer* pick.

Plus, it's chic right now.

For the companies marketing these bobtail aero helmets the big challenge will be to produce that de facto, "golden BB" metric, the vaunted "white paper" that people like to throw around to prove its "betterness".

That is so cornerstone to marketing in this industry. A chart showing other aero helmets with lots of lines and "X" and "Y" axis with one of these designs either at the top or bottom of "betterness" is all it will take. Some photos from the wind tunnel won't hurt either. Add one to the head of an Ironman winner they will go out the door so fast dealers willl have to take their hinges off.

Once that "data" is established for the forums to link to and reference, the sales loop will be closed. Then it is just a matter of Visa or Mastercard. Until then, the debates will rage...

One reason why this new-ish category may hunt is that they are more visually digestible than pointy-tail aero helmets. Nothing screams "tri geek" (and I use that term in the most endearing way as one myself) like a pointy-tail helmet. The appearance of these bobtail helmets may be more appealling and conventional (wearable) to a larger segment of the triathlon population who doesn't always want to look like they are setting an hour record or trying to win the final time trial in the Tour de France.

We'll see....   I do like new product categories though. Always fun.

Who's actually selling these stubby aero helmets now?  I looked on Kask's site and I didn't see a stubby helmet listed.

Giro has one coming out, but it looks like it's not going to be out until next year.

What's the current 'rumor' regarding these helmets?  Are they said to be more aero at yaw than pointies?  Are they more aero when looking down and there's a reason to look down a lot? 

They must have some, at least perceived, advantage for them to have been chosen by a pro team.

Old is the new, what's next flannel shirts and Timberland boots!  Glad I got my shorty LG on Nashbar 50% off closeout with free shipping back when the long pointy helmets were the hot new thing!

From what i've seen/read/heard about the stubby helmets the aero effect is more to do with wind than body/aero position.  The theory (if i've understood it right) being both styles provide similar levels of aero if the air is still (i.e. no wind); if the wind is blowing directly against you from the front then the longtail helmet provides more aero (how often is the wind going to do this??); if the wind direction varies even slightly from directly against you then the resultant crosswind effect on a longtail helmet works against any aero effect therefore making the stubby the more aero helmet.

Does that make sense?

Yup!  I'm still deciding on which one to get.

The bobtails will start to show up later this year at retail.

Here's a nice cat instead of that duplicate post.  

I didn't see the nice cat. =(

Well... what you're saying sort of does and sort of doesn't... as you go faster yaw DEcreases... so if a long tail is really faster from straight ahead, then guys like Wiggins probably should be wearing long tail helmets. (I mean... he rides a Trispoke... same scenario)

From my own experience, a stub helmet was slower than a Rudy Wingspan (which isn't exactly Long tailed, but longer) at 0 and 10 degree yaw.

giro air attack, looks pretty sweet to me

Interesting.

An aero helmet is in the very back of my mind but I just can't get passed the appearance. I race a lot of small local races and am usually one of a handful of ladies that even rides a tri bike. The aero helmet seems like overkill but at the same time I would like to do what I can to get faster. At this point I can continue to work a lot harder on my bike though.

Here is what I would be looking at to put down the cash - is the stubby going to be faster than the vented Bell helmet I'm wearing now? Assuming yes and price points of stubby  vs pointy are close then that is what I would go with.

The part about the head on doesn't make sense. It's all about the rider's speed relative to the air. It doesn't matter if the rider is going faster  in still air or if there is a headwind. 25 mph relative air speed is 25 mph no matter how you get there. It does change where the rolling resistance will be at as the rider will be at different speeds relative to the ground, but aero benefits are relative to air speed.

That is my understanding as well, and makes aerodynamic sense.   On that topic, what one *thinks* is aerodynamic is not necessarily the case.  In the aircraft wing design, one has to consider the type of boundary layer flow desired/encountered, which would be laminar, turbulent or separated (in aircraft design this latter one produces no lift and the aircraft stalls).  Typically turbulent flow involves more energy, and therefore drag,  than laminar flows.  That is where the pointy helmets come from (and wind tunnel tests), the idea that air coming straight at you needs to be laminar all the way down, so they engineer the helmet to avoid the boundary layer to become turbulent.   The downside, as you put it, is that air doesn't come straight at you, but at an angle, about 99% of the time in the real world, so pointy helmets don't get the full benefit.  The non-pointy TT helmets acknowledge this and attempt to keep some laminar flow around the front and over the top, but seek to separate the helmet from the air flow downstream while avoiding boundary layer separation.  They do this in a variety of ways and shapes, but effective ones like the LG Black Knight use golf ball dimples for the laminar frontal section, high pressure intake at the front, and low pressure outake at the back (sucking the boundary layer from the helmet into a rear exit as opposed to separating).  Their shape is more conducive to side impigement as well.

Yep, that's what I meant!!

What cracks me up about all of this is that this is all the second go round for all of this. Anyone remember the aerodyne hemlet and then short after the Giro Lemond wore to victory? Aero helmets were the fastest thing you could by based on wind tunnel data then too. Then they tightened up the tail. See the pic below of Paula in the 1997 Ironman. No vents, snubbed nose. 1997.

I'm going to just take a guess that the experts will discover that they can make a relatively aero helmet, but with vents, as they discover that the cooling effect on the body far outweighs the extreme aero benefits. So they will come out with ridiculously light helmets (Sub 6 anyone?). Just a guess....or maybe just that I raced through the '90's, so I already know how this history repeats itself!haha

(pnf97.jpg)

So what kind of helmet do you race in?