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4947 Views 5 Replies Latest reply: Feb 12, 2009 9:00 AM by dkhartung RSS
dkhartung Pro 98 posts since
Aug 2, 2007
Currently Being Moderated

Jan 7, 2009 8:01 AM

Total impact of Aero helmets

 

I'm looking for opinions regarding aero helmets; specifically, I'd like to better understand the real impact across overall triathlon performance.  After looking at some of the windtunnel research I have no doubt that a more aero helmet helps to reduce drag leading to a faster bike split.  Great for a timetrialist, but I'm wondering if anyone has seen any data on the impact this may have on real world performance in Olympic of 1/2 Iron distance races.  My concerns are:

 

 

-  My biking improved last year (holding just north of 20mph pace for a 40K in Olympic distance tris).  I'm working hard this offseason to improve, but "free speed" through lower drag is obviously attractive.  That said, I assume that the drag improvement is only realized if one can maintain proper head position.  Otherwise, the tail of the helmet could end up acting like a parachute!  Also, if one is able to maintain proper head position for the entire ride, can this result is neck and shoulder stiffness affecting the run?

 

 

-  I race primarily in the MidWeststern US.  That means the bike leg is often taking place with weather in the 80s and humidity in the 80% range.  Aero helmets do not appear to have much ventilation for obvious reasons (more ventilation, less aero).  To what extent does one end up with a faster bike split, but greater dehydration coming off the bike, and therefore a much tougher run.  Sure, the obvious answer is to drink more on the bike, but I'm not sure if I can carry or consume much more as I already put down 60-70 oz. over a 56 mile bike leg, and often grab another bottle along the way.

 

 

So, is anyone aware of more holistic research that looks at both improved aerodynamics on the bike leg AND the potential negative effects on the run?  Personal experiences?

 

 

Happy training,

 

 

Douglas

 

 

  • Rob Hatch Rookie 2 posts since
    Mar 24, 2008
    Currently Being Moderated
    1. Jan 12, 2009 7:33 AM (in response to dkhartung)
    Re: Total impact of Aero helmets

     

    This is totally anecdotal, but here is my experience:

     

     

    2 years ago, I was pit crew for my daughter, and stood around several transition areas as the leaders came in off the bike.  In every race, nearly all of the first 10 off the bike wore aero helmets.  After that, the proportion with aero helmets fell steadilly.  That got my attention and I bought one. I was very concerned about getting too hot, since I race in Florida.  I did a couple training rides mid afternoon (temp in low 90's and very humid).  The biggest surprise was how uncomfortably warm your ears get when they're covered.  I was eager to get it off at the end of the ride, but after a few rides I adjusted to it - just like you adjust to a new seat position, pair of shoes, whatever.  I certainly don't think it increased my fluid losses.  The helmet only covers a couple percent of your surface area, surface area that is already insulated by hair.  so compared to a non-aero, maybe a couple tents of a percent difference in surface area ventillated.  So, not as comfortable, but I doubt any fluid impact. 

     

     

    I know I couldn't stand the helmet for a really hot Florida 1/2 iron.  I could for Panama City in May (mid 70-s building to mid 80's) but not for Clermont in Sept (low 80s building to low 90s).  But it was no problem for 2 florida olys.  In fact, since I read that the vents create the biggest part of the drag, I start every race with the vents taped over by scotch tape.  Then if my head starts feeling too hot, I reach up and punch my finger tip through the tape.  At St Anthony's, which I am guessing has conditions similar to your races, I did the whole race with vents taped and had no problem.

     

     

    Re: tail position, I had someone video me and saw the tail was sitting a bit high.  It was a piece of cake to adjust the straps so that in my normal aero position, it was down almost touching my back.  I'm very horizontal on the bike, and I am guessing this would be tougher if you are a little more upright.

     

     

    Good luck.  rob

     

     

  • Angrenbarad Rookie 1 posts since
    Nov 24, 2008
    Currently Being Moderated
    2. Jan 12, 2009 6:24 PM (in response to dkhartung)
    Re: Total impact of Aero helmets

     

    Douglas,

     

     

    I can't speak from my experience, but a friend of mine picked up an aero helmet last year and increased his 1/2IM bike split by more than 1mph.  Even though we're both clydesdales, he's broader-chested than I and has trouble with overheating on the runs on humid days.  From what I've seen him do, the helmet doesn't detract from his run.

     

     

    I haven't picked one up for me because I tend to do quite a bit of looking around to keep my neck loose (previous surgery) while I'm on the bike and know that big tail on an aero helmet would be increased drag when I turn my head.

     

     

    Aero helmets can definitely make a difference if you can keep a good position, unlike me.

     

     

         Hope that helps,

     

     

                                       Ian

     

     

  • IronMakeover Community Moderator 738 posts since
    Jul 7, 2008
    Currently Being Moderated
    3. Jan 17, 2009 10:31 AM (in response to dkhartung)
    Re: Total impact of Aero helmets

    Hi Douglas,

     

    This Bikesport Michigan article will help. "Speed for Sale"

     

     

    http://www.bikesportmichigan.com/features/aero_helmet.shtml

     

     

    It reads:

     

     

    "A corroboration of studies from Texas A&M University to M.I.T. has accurately quantified the benefit of tear drop shaped aerodynamic time trial helmets. While each of these studies produce varied results about what the time savings actually are the end results are unanimous: An aero helmet saves time. Studies show time savings that range from as little as 30 seconds to as much as 2 minutes over 25 miles (40 kilometers, an Olympic triathlon bike distance).

    At an Ironman distance triathlon an aero helmet could save between 3 and 6 minutes"

     

     

    Hmm. I could definitely use a new helmet...

     

     

    Sara





    Sara Cox Landolt

    http://www.ironmakeover.blogspot.com/

  • IronMakeover Community Moderator 738 posts since
    Jul 7, 2008
    Currently Being Moderated
    4. Feb 21, 2009 8:00 AM (in response to IronMakeover)
    Re: Total impact of Aero helmets

    Another opinion on aero helmets, this time from Canadian triathletes Trevor & Heather Wurtele

     

    http://ironmantriathlontips.com/2009/02/07/aero-helmets/

     

     

    Sara

     

     

    *update

     

     

    Doug, I know this didn't answer your whole question. I think your idea for a study looking at the overall impact of aero helmets across the bike and run legs would be a great thesis for someone! So far no luck finding this answer.





    Sara Cox Landolt

    http://www.ironmakeover.blogspot.com/

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