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2016-03-30 12:16 PM
in reply to: marcag

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Subject: RE: How aero are you ?

Great chart! 

I plugged in the speed from a Sprint last year where I know that I averaged 240 watts and was surprised that I was in the 'average' to 'poor' range.  The coffee must not have kicked in and it took me awhile to realize I was looking at the online results and so the bike time was measured from the transition mat and it was a bit of a run to get to the start line and fumble into the pedals.  I'll have to look at the garmin file when I get home.

I see that a lot of knowledgeable people have posted to this thread and so maybe we can get a dialogue going of how to improve CDA.  Assuming that a fit is dialed in and you're working with the usual aero equipment (wheels, disc cover, helmet), what other steps can you take to reduce your CDA?  The following come to mind off-hand that typically will improve your aeroness:

  • bars narrow together and titled slightly up
  • "turtle" your head between your shoulders
  • clean up cables to get out of the wind
  • bottle between the arms
  • shaved legs
  • tight fitting clothing - I understand that sleeved tops have tested faster than sleeveless
  • taking advantage of legal drafting - draft zone for AGers in my area is 5 metres and rider has 15 seconds to complete pass

I know that testing will ultimately determine what works for each rider, but are there any other general aero tips?

 



2016-03-30 1:17 PM
in reply to: Scott71

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Subject: RE: How aero are you ?
Originally posted by Scott71
:

  • bars narrow together and titled slightly up
  • "turtle" your head between your shoulders
  • clean up cables to get out of the wind
  • bottle between the arms
  • shaved legs
  • tight fitting clothing - I understand that sleeved tops have tested faster than sleeveless
  • taking advantage of legal drafting - draft zone for AGers in my area is 5 metres and rider has 15 seconds to complete pass

I know that testing will ultimately determine what works for each rider, but are there any other general aero tips?

 




*bars narrow is often neutral, bars up is usually at least OK until you start really adding °
* shrug, turtle, duck, roll your shoulders, etc... I don't think I've ever seen it slower for anyone... but it takes a LOT of practice and generally a very stretched out front end to hold it for extended periods
* cables are bad
* torpedo bottle is usually neutral. Less likely to be neutral the higher you raised your bars though.
* despite the sketchiest wind tunnel results ever, I have not found the length of my leg hair to effect my results much in testing. It's just as possible the *right* leg hair is better than no leg hair.
* sleeves are usually good, tight is always good. Wrinkles are bad. Clothing is VERY personal. Probably just as/more personal than helmets.
* drafting is always good (as long as it's legal.)

TEST TEST TEST. Question everything. That's how you get lower cda. Not having to swim or run is helpful as well.
2016-03-30 3:24 PM
in reply to: Leegoocrap

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Subject: RE: How aero are you ?
Originally posted by Leegoocrap

Originally posted by bcagle25

Originally posted by marcag

Originally posted by bcagle25

I would more like to see a chart of bike time and run times combined with how aero people are. Those that sacrifice biomechanics for a little extra savings....wish there could be a way to measure and see the cost.


There are several metrics that are taken from the Retul data that Andy will not compromise on.


Such as....?


I would assume it's the hip angle and pelvic tilt. bdc and tdc also possibly, but that's just a guess.


Yes but that is not what I am getting at.

Biomechanics first. It will always trump aerodynamics.

Think of it this way....

Lets say you get in the most aero position possible. How much percentage did you save? How much time did you save?

Now lets say you go and do an Ironman. That position you are in you can hold well for 80 miles, then the last 30 or so you are in and out of the aero position. I promise you every time, that the drag you add by sitting up on the hoods will negate everything you earned and then some by getting as aero as possible.

So the big caveat with all of this, is that whatever aero position you are in, it is assumed you can hold it for it's entirety for the full ride. I think this part gets looked over a lot.
2016-03-30 3:45 PM
in reply to: 0

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Subject: RE: How aero are you ?
Originally posted by bcagle25

Originally posted by Leegoocrap

Originally posted by bcagle25

Originally posted by marcag

Originally posted by bcagle25

I would more like to see a chart of bike time and run times combined with how aero people are. Those that sacrifice biomechanics for a little extra savings....wish there could be a way to measure and see the cost.


There are several metrics that are taken from the Retul data that Andy will not compromise on.


Such as....?


I would assume it's the hip angle and pelvic tilt. bdc and tdc also possibly, but that's just a guess.


Yes but that is not what I am getting at.

Biomechanics first. It will always trump aerodynamics.

Think of it this way....

Lets say you get in the most aero position possible. How much percentage did you save? How much time did you save?

Now lets say you go and do an Ironman. That position you are in you can hold well for 80 miles, then the last 30 or so you are in and out of the aero position. I promise you every time, that the drag you add by sitting up on the hoods will negate everything you earned and then some by getting as aero as possible.

So the big caveat with all of this, is that whatever aero position you are in, it is assumed you can hold it for it's entirety for the full ride. I think this part gets looked over a lot.


A good fitter can get a person very aerodynamic without compromising biomechanics..

The numbers on that chart (from better and down) are achievable by many many people for a full IM. Guys like Cody Beals, Rapp and Lionel are between better and best,

  • 21 is tougher but certainly sustainable for an Oly.

  • I won't publish Chris' numbers but he is off this chart. By a lot. But his position is not sustainable for triathlon, never mind an IM.

    Lionel before getting in his new position could not hold aero position, and wasn't all that aero. He now can hold it, can do more watts and is a lot more aero.


    Edited by marcag 2016-03-30 3:45 PM
    2016-03-30 3:46 PM
    in reply to: marcag

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    Subject: RE: How aero are you ?

    Originally posted by marcag
    Originally posted by bcagle25
    Originally posted by Leegoocrap
    Originally posted by bcagle25
    Originally posted by marcag
    Originally posted by bcagle25 I would more like to see a chart of bike time and run times combined with how aero people are. Those that sacrifice biomechanics for a little extra savings....wish there could be a way to measure and see the cost.
    There are several metrics that are taken from the Retul data that Andy will not compromise on.
    Such as....?
    I would assume it's the hip angle and pelvic tilt. bdc and tdc also possibly, but that's just a guess.
    Yes but that is not what I am getting at. Biomechanics first. It will always trump aerodynamics. Think of it this way.... Lets say you get in the most aero position possible. How much percentage did you save? How much time did you save? Now lets say you go and do an Ironman. That position you are in you can hold well for 80 miles, then the last 30 or so you are in and out of the aero position. I promise you every time, that the drag you add by sitting up on the hoods will negate everything you earned and then some by getting as aero as possible. So the big caveat with all of this, is that whatever aero position you are in, it is assumed you can hold it for it's entirety for the full ride. I think this part gets looked over a lot.
    A good fitter can get a person very aerodynamic without compromising biomechanics.. The numbers on that chart (from better and down) are achievable by many many people for a full IM. Guys like Cody Beals, Rapp and Lionel are between better and best, .21 is tougher but certainly sustainable for an Oly. I won't publish Chris' numbers but he is off this chart. By a lot. But his position is not sustainable for triathlon, never mind an IM. Lionel before getting in his new position could not hold aero position, and wasn't all that aero. He now can hold it, can do more watts and is a lot more aero.

     

    I have a question, could being too narrow on the bars or in a bad position impact my ability to breathe when I get on the run?

    2016-03-30 3:49 PM
    in reply to: dmiller5

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    Subject: RE: How aero are you ?
    Originally posted by dmiller5
    I have a question, could being too narrow on the bars or in a bad position impact my ability to breathe when I get on the run?




    There is a guy on ST that seems to make a lot of sense and says that excess posterior tilt does reduce the ability to breath. But that's all I have ever heard on it.


    2016-03-30 3:50 PM
    in reply to: marcag

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    Subject: RE: How aero are you ?

    Originally posted by marcag
    Originally posted by dmiller5 I have a question, could being too narrow on the bars or in a bad position impact my ability to breathe when I get on the run?
    There is a guy on ST that seems to make a lot of sense and says that excess posterior tilt does reduce the ability to breath. But that's all I have ever heard on it.

    interesting, I have exercise induced asthma that is much more frequent running off the bike. Part of this is because of level of exertion, but I'm starting to become convinced part of it is the position.

    2016-03-30 4:54 PM
    in reply to: bcagle25

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    Subject: RE: How aero are you ?
    Originally posted by bcagle25


    Yes but that is not what I am getting at.

    Biomechanics first. It will always trump aerodynamics.

    Think of it this way....

    Lets say you get in the most aero position possible. How much percentage did you save? How much time did you save?

    well, looking at Marc's chart... sometimes a LOT.

    Now lets say you go and do an Ironman. That position you are in you can hold well for 80 miles, then the last 30 or so you are in and out of the aero position. I promise you every time, that the drag you add by sitting up on the hoods will negate everything you earned and then some by getting as aero as possible.

    generally I'd agree with you. However that will depend on your cda on the hoods as well, and just how much the gap between your "sustainable" position and your "as aero as possible" position. But for the most part you're right... same as not following your nutrition plan, pacing, etc will all negate everything you earned on paper.


    So the big caveat with all of this, is that whatever aero position you are in, it is assumed you can hold it for it's entirety for the full ride. I think this part gets looked over a lot.


    I agree... specific training for specific results (and events) which is something every athlete (and coach) should go into with a realistic view.


    2016-03-30 6:12 PM
    in reply to: 0

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    Subject: RE: How aero are you ?
    Originally posted by Scott71

    Great chart! 

    I plugged in the speed from a Sprint last year where I know that I averaged 240 watts and was surprised that I was in the 'average' to 'poor' range.  The coffee must not have kicked in and it took me awhile to realize I was looking at the online results and so the bike time was measured from the transition mat and it was a bit of a run to get to the start line and fumble into the pedals.  I'll have to look at the garmin file when I get home.

    I see that a lot of knowledgeable people have posted to this thread and so maybe we can get a dialogue going of how to improve CDA.  Assuming that a fit is dialed in and you're working with the usual aero equipment (wheels, disc cover, helmet), what other steps can you take to reduce your CDA?  The following come to mind off-hand that typically will improve your aeroness:

    • bars narrow together and titled slightly up
    • "turtle" your head between your shoulders
    • clean up cables to get out of the wind
    • bottle between the arms
    • shaved legs
    • tight fitting clothing - I understand that sleeved tops have tested faster than sleeveless
    • taking advantage of legal drafting - draft zone for AGers in my area is 5 metres and rider has 15 seconds to complete pass

    I know that testing will ultimately determine what works for each rider, but are there any other general aero tips?

     




    Scott,

    A few comments. Arms narrow is good, but sometimes too much. Narrower than hips for sure, but sometimes narrow locks your head into a position and head down is critical
    Hands slighly up works for a lot of people, But it depends on your setup. You want to keep your bottle, etc level and you don't want to tilt your basebar.: very important.
    Turtling very important but depends a lot on fit.
    Cable cleanup is important but don't go nuts drilling frame (IMO)
    Bottle between the arms is good, but for some bikes, a Torhans can be equally good if not better. Keep the bottle level.
    Sleeved tops, tight helps. But you need to be able to put it on and/or swim. Big cylinders are not aero. Those are the biggest cylinders exposed. if you can't test pick a proven brand.
    Speaking of cylinders, the more spacers, the more you are exposing a big cylinder to the wind. There are ways to reduce this.

    Rear hydration can help or be neutral.

    I cannot say this enough. The first step is a good fit from someone that appreciates the aero aspect. Comfort is critical, power production is critical. Aero is as well. It's not all of one or all the other, it's the balance between the three and there is a way to find balance.


    Edited by marcag 2016-03-30 6:15 PM
    2016-03-31 10:01 AM
    in reply to: marcag

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    Subject: RE: How aero are you ?

    3mar got me thinking on the other thread about aero position as it applies to wind.  Is there a wind speed when being in aero is no longer optimal? (going with the wind)  At some point, it's got to be better to sit up and catch some wind right?

    I once had my wife drive me 20 miles to the west in Nebraska because the wind was straight out of the west at 40 mph gusting to 55-60. (straight east/west running county road) I rode those 20 miles like I was shot out of a cannon. LOL

    2016-03-31 10:07 AM
    in reply to: Left Brain

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    Subject: RE: How aero are you ?

    Originally posted by Left Brain

    3mar got me thinking on the other thread about aero position as it applies to wind.  Is there a wind speed when being in aero is no longer optimal? (going with the wind)  At some point, it's got to be better to sit up and catch some wind right?

    I once had my wife drive me 20 miles to the west in Nebraska because the wind was straight out of the west at 40 mph gusting to 55-60. (straight east/west running county road) I rode those 20 miles like I was shot out of a cannon. LOL

    its only better to sit up when the wind speed is greater than your speed.  So if its blowing 20 and you're riding uphill at 15...sit up!



    2016-03-31 10:11 AM
    in reply to: 0

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    Subject: RE: How aero are you ?
    Originally posted by dmiller5

    Originally posted by Left Brain

    3mar got me thinking on the other thread about aero position as it applies to wind.  Is there a wind speed when being in aero is no longer optimal? (going with the wind)  At some point, it's got to be better to sit up and catch some wind right?

    I once had my wife drive me 20 miles to the west in Nebraska because the wind was straight out of the west at 40 mph gusting to 55-60. (straight east/west running county road) I rode those 20 miles like I was shot out of a cannon. LOL

    its only better to sit up when the wind speed is greater than your speed.  So if its blowing 20 and you're riding uphill at 15...sit up!




    I'd say it depends on power. If you can produce more power out of the aero bars, then that scale slides. If you are riding 20 mph with a 15 mph tail wind, your wind speed is 5mph, however, if you can produce more power up out of the aerobars, you still may be better off wind-wise. I've noticed I produce more power and I am more comfortable in aero than out, so I'd stay in regardless unless the wind was actually greater than my speed by enough that 'catching' it would help.

    Edited by 3mar 2016-03-31 10:11 AM
    2016-03-31 10:21 AM
    in reply to: 3mar

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    Subject: RE: How aero are you ?

    Originally posted by 3mar
    Originally posted by dmiller5

    Originally posted by Left Brain

    3mar got me thinking on the other thread about aero position as it applies to wind.  Is there a wind speed when being in aero is no longer optimal? (going with the wind)  At some point, it's got to be better to sit up and catch some wind right?

    I once had my wife drive me 20 miles to the west in Nebraska because the wind was straight out of the west at 40 mph gusting to 55-60. (straight east/west running county road) I rode those 20 miles like I was shot out of a cannon. LOL

    its only better to sit up when the wind speed is greater than your speed.  So if its blowing 20 and you're riding uphill at 15...sit up!

    I'd say it depends on power. If you can produce more power out of the aero bars, then that scale slides. If you are riding 20 mph with a 15 mph tail wind, your wind speed is 5mph, however, if you can produce more power up out of the aerobars, you still may be better off wind-wise. I've noticed I produce more power and I am more comfortable in aero than out, so I'd stay in regardless unless the wind was actually greater than my speed by enough that 'catching' it would help.

    And before anyone gets too carried away with that, keep in mind that those of use who make more power up than down should still not see that much of a gap in either position. Otherwise take another look at it.

    2016-03-31 11:48 AM
    in reply to: dmiller5

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    Subject: RE: How aero are you ?

    Originally posted by dmiller5

    Originally posted by Left Brain

    3mar got me thinking on the other thread about aero position as it applies to wind.  Is there a wind speed when being in aero is no longer optimal? (going with the wind)  At some point, it's got to be better to sit up and catch some wind right?

    I once had my wife drive me 20 miles to the west in Nebraska because the wind was straight out of the west at 40 mph gusting to 55-60. (straight east/west running county road) I rode those 20 miles like I was shot out of a cannon. LOL

    its only better to sit up when the wind speed is greater than your speed.  So if its blowing 20 and you're riding uphill at 15...sit up!

    Threre was an extremely funny but true statement on ST made a few years ago on this subject.  They said to tie a light string or ribbon to your handlebars...and if that ribbon is ever leaning or pointing forward, you can sit up.  

    2016-04-04 1:09 PM
    in reply to: marcag

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    Subject: RE: How aero are you ?

    OK Marc, now that I have some data fresher than two years old, a fit tweak from Jim Manton at ERO and a couple mew toys, can this be used at a semi hilly course like Oceanside (approx 2400 feet elevation)?  I know the caption says flat course...   But my bike time was decent but shows up in the "poor" column unless I am totally reading it wrong (a distinct possibility!).   

    I have a flattish (1500 foot elevation) HIM coming up and I'd like to do well there.

    Time was 2:48 on 187AP/208 NP.   195#.  Anything you can tell me from that info?  Or need more info?

    I am not very good at these technical discussions, and usually just look at the pretty pitchurs....

    2016-04-04 1:18 PM
    in reply to: ChrisM

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    Subject: RE: How aero are you ?
    Originally posted by ChrisM

    OK Marc, now that I have some data fresher than two years old, a fit tweak from Jim Manton at ERO and a couple mew toys, can this be used at a semi hilly course like Oceanside (approx 2400 feet elevation)?  I know the caption says flat course...   But my bike time was decent but shows up in the "poor" column unless I am totally reading it wrong (a distinct possibility!).   

    I have a flattish (1500 foot elevation) HIM coming up and I'd like to do well there.

    Time was 2:48 on 187AP/208 NP.   195#.  Anything you can tell me from that info?  Or need more info?

    I am not very good at these technical discussions, and usually just look at the pretty pitchurs....




    Send me your Garmin file :-) PM me a Garmin connect link if you want


    2016-04-04 1:28 PM
    in reply to: marcag

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    Subject: RE: How aero are you ?
    Marc-Am I understanding the first table correctly-an average aero rider should be able to go 20 mph on 155 Watts?
    That seems low.

    I know it goes along with the 'bikecalculator' model, but my real world data isn't close. Of course, I am a human parachute...
    2016-04-04 1:41 PM
    in reply to: dtoce

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    Subject: RE: How aero are you ?
    Originally posted by dtoce

    Marc-Am I understanding the first table correctly-an average aero rider should be able to go 20 mph on 155 Watts?
    That seems low.

    I know it goes along with the 'bikecalculator' model, but my real world data isn't close. Of course, I am a human parachute...


    You may have multiple things going on

    Bad CRR (tires) are big
    Being a parachute is big
    A PM reading a few watts high is common

    The model work incredibly well in real life and the reason people should test


    2016-04-04 1:51 PM
    in reply to: 0

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    Subject: RE: How aero are you ?

    Sent

    Thanks

    And more on equipment to the extent relevant

    BMC TM02
    HED 3 front, 23 mm Conti 4000ii
    PT rear with disc cover
    Specialized SW TT helmet
    Torhans frame bottle flat kit
    Xlab versa BTA
    XLab BTS (one cage)



    Edited by ChrisM 2016-04-04 1:53 PM
    2016-04-04 1:57 PM
    in reply to: ChrisM

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    Subject: RE: How aero are you ?
    Well, I'm officially average. Taking out the data from when I'm getting in/out of my shoes from my last race, 25.1 mph on 277 watts. Guess I need to look into a new fit.
    2016-04-04 2:07 PM
    in reply to: ChrisM

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    Subject: RE: How aero are you ?

    Originally posted by ChrisM


    HED 3 front, 23 mm Conti 4000ii




    2016-04-04 2:13 PM
    in reply to: Jet Black

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    Subject: RE: How aero are you ?
    Originally posted by Jet Black

    Well, I'm officially average. Taking out the data from when I'm getting in/out of my shoes from my last race, 25.1 mph on 277 watts. Guess I need to look into a new fit.


    Hey, I recognize you from the race! I think the rough road conditions on the way back altered the numbers a bit. I know I was getting caught up in a lot of that patchy asphalt on the way back and it was really slowing me down. Doing the same as you, and cutting off the beginning and the end I was at 23.1 mph on 216....so in the same boat as far as "good", of course, without so much power.
    2016-04-04 2:13 PM
    in reply to: ChrisM

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    Subject: RE: How aero are you ?
    Originally posted by ChrisM

    Sent

    Thanks

    And more on equipment to the extent relevant

    BMC TM02
    HED 3 front, 23 mm Conti 4000ii
    PT rear with disc cover
    Specialized SW TT helmet
    Torhans frame bottle flat kit
    Xlab versa BTA
    XLab BTS (one cage)




    Setting up the model is time consuming but I don't mind doing it because I have to do it for someone else that did this race. And I like you :-)

    But after my ride later ...priorities priorities




    2016-04-04 2:13 PM
    in reply to: Leegoocrap

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    Subject: RE: How aero are you ?

    Originally posted by Leegoocrap
    Originally posted by ChrisM
    HED 3 front, 23 mm Conti 4000ii

    Yeah, I know.    

    21 on that front worries me a bit *especially* at oceanside which has some really bad pavement sections with nice longitudinal cracks.

    2016-04-04 2:15 PM
    in reply to: marcag

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    Subject: RE: How aero are you ?

    Marc, thanks much. please don't go out of your way.  Just more out of curiosity than anything else.   Jim at ERO has told me my fit is really good, and it feels good on the bike.  But it doesn't correlate at all with your table.  I don't think...

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