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Aerodynamic Hierarchy
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I have been looking a little for an article I thought I read a long time ago about the aerodynamic hierarchy. Does anyone have any links for this sort of thing? I thought it referenced that specifically the hierarchy was 1. Good Fit; 2. Bike; 3. Helmet; 4. Wheels; 5. Water bottles...etc.
I'm just trying to research for a friend about the order of benefit.
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Re: Aerodynamic Hierarchy [davedaprato] [ In reply to ]
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There are probably a number of them out there. Here are a few that came up with a Google search:

https://sites.google.com/...tspendingalotofmoney

https://cyclingtips.com/...ime-trial-equipment/ from this article:


http://www.aerosportsresearch.com/pdf/buying-time.pdf


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Re: Aerodynamic Hierarchy [davedaprato] [ In reply to ]
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Generally understood to be....

1. Your body position
2. clothing fit
3. helmet
4. front wheel
5. rear wheel
6. bike
7. front end setup of bike (handlebars, aerobottle Y/N)
8. additional bottle carriage
9. Cabling

then... you are really getting into miniscule things like pedals etc...

Of course some of those are inter-related (2&3 to 1)

David T-D
http://www.tilburydavis.com
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Re: Aerodynamic Hierarchy [davedaprato] [ In reply to ]
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It's almost impossible to give a strict hierarchy because the curve of performance gains for the various aero improvements are not the same. Some are very steep at the bottom end but flatten considerably at the top, and the differences between "pretty good" and "great" are very small. Others are closer to linear, where every step up the ladder in quality gives a similar performance gain. So the answer to the question depends somewhat on where you start.

I like to fiddle with the Aeroweenie Aero Assistant. It's not the "definitive" model for aero improvements, but it seems to be a well-reasoned one. One thing that stands out to me is how much difference they say there is between a premium aerobar set up and a middle tier one compared how little the difference they say there is between a middle tier, upper-middle tier, and high end frame. Another is how overvalued high end wheels are in their estimation. Their model suggests a set of high end, deep-aero front/rear disc wheels is worth only 17 seconds on a 40k over a 30mm semi-aero alloy wheels with a ~$100 Wheel Builders cover for the rear.
Last edited by: gary p: Mar 9, 17 6:49
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Re: Aerodynamic Hierarchy [gary p] [ In reply to ]
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cool. thanks. I definitely understand the "it depends" case. I was just looking for some general guidelines for a friend, and some literature to support the guidelines. What really lacks in triathlon are RTC's by independent researchers. I'm sure we are very far off from that point in the future though.
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Re: Aerodynamic Hierarchy [davedaprato] [ In reply to ]
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I wrote this back in 2008 for a tri publication and later hosted the (un-edited) article on my site:


http://biketechreview.com/...s/477-speed-for-sale


I'm not sure I'd change anything ~10 years later (higher rating is more important)






it's cool to see slowtwitchers adopting these early insights over time (hey, tires and clothing are pretty big deals! ;-) )

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Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
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Re: Aerodynamic Hierarchy [BikeTechReview] [ In reply to ]
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Certainly an interesting article. Thanks Kraig. It brings up for me lots and lots of questions. :). When I started the thread I had a colleague say to me that he thought more aerodynamic wheels give more bang for the buck than other things like helmet and clothing. So I aimed to help him understand that there is lots more going on in the picture, but that generally assuming you are racing with a standard road helmet, it is more important to get an aero helmet than it is to get deeper carbon wheels. I would love to see RCT's that compare lots of constant variables with tire width, tread, rolling resistance, etc. And so on for other demand type products. Though, I'm sure overhead cost is the limiting factor. Thanks again!
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Re: Aerodynamic Hierarchy [BikeTechReview] [ In reply to ]
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Another thought as I have been reading various articles on biketechreview...what were the rim widths of the tested wheels in the tire study? Have you looked at doing the same testing with wheels like Flow and wider Zipps? Listening to various conversations between other athletes and reported benefits of a wider rim, it seems like a wider rim, say 25mm and a narrow tire, like 20-21mm is ideal aerodynamics. Do you think that reigns true? We just need lots of funding for your lab and no problem. :)
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Re: Aerodynamic Hierarchy [davedaprato] [ In reply to ]
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davedaprato wrote:
Listening to various conversations between other athletes and reported benefits of a wider rim, it seems like a wider rim, say 25mm and a narrow tire, like 20-21mm is ideal aerodynamics. Do you think that reigns true? We just need lots of funding for your lab and no problem. :)

Tom A's got you covered. Though they didn't test nearly what you describe - 20-21mm on wide rims, they did test down to 22m. And there's apparently little benefit vs. 23mm/24mm tires. Once you add in rolling resistance (another graph on the same site), the overall performance gap between narrow and wide tire becomes effectively nothing for wider rims.

Also most manufactures of high-performing aero wheels explicitly state that they design around 23mm tires.



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Re: Aerodynamic Hierarchy [BikeTechReview] [ In reply to ]
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Positioning is definitely number one. Too many riders with all the flash kit have CdAs that make a stack of pallets look like a feat of aerodynamic genius.
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Re: Aerodynamic Hierarchy [davedaprato] [ In reply to ]
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davedaprato wrote:
Another thought as I have been reading various articles on biketechreview...what were the rim widths of the tested wheels in the tire study?


I don't have that info handy - but i have installed widths on the three spoke:



and the 1080:



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Have you looked at doing the same testing with wheels like Flow and wider Zipps?

Flow and zipp haven't really been doing anything that has piqued my interest. I probably won't front the money for a tunnel test any longer. I've toyed in the past with the concept that pubes has tried to make happen, but if $1k is all that can be drummed up for a complicated test of complete bikes, that idea loses some luster...

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Listening to various conversations between other athletes and reported benefits of a wider rim, it seems like a wider rim, say 25mm and a narrow tire, like 20-21mm is ideal aerodynamics. Do you think that reigns true? We just need lots of funding for your lab and no problem. :)

I think what reigns true is that a narrow, well-shaped, low crr tire is needed in the market.

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Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
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Re: Aerodynamic Hierarchy [trail] [ In reply to ]
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trail wrote:
Also most manufactures of high-performing aero wheels explicitly state that they design around 23mm tires.

I've tunnel tested some high performing aero wheels with both 23 and 20 mm tires. They may state they design around 23mm tires, but that doesn't really address which tire is most aerodynamic.

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Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
=================
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Re: Aerodynamic Hierarchy [BikeTechReview] [ In reply to ]
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BikeTechReview wrote:
trail wrote:

Also most manufactures of high-performing aero wheels explicitly state that they design around 23mm tires.


I've tunnel tested some high performing aero wheels with both 23 and 20 mm tires. They may state they design around 23mm tires, but that doesn't really address which tire is most aerodynamic.

True. But at least in what I've seen publicly available, I've never been all that impressed by *anything* with narrow (<22m) tires. Even the HED3. (ignoring the watts-to-spin). I've heard several claim they've done personal testing, or testing they can't release. I just haven't seen it.
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Re: Aerodynamic Hierarchy [trail] [ In reply to ]
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The cycling world just needs a few key benefactors to provide good quality research. So simple...not. :/
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Re: Aerodynamic Hierarchy [trail] [ In reply to ]
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trail wrote:
BikeTechReview wrote:
trail wrote:

Also most manufactures of high-performing aero wheels explicitly state that they design around 23mm tires.


I've tunnel tested some high performing aero wheels with both 23 and 20 mm tires. They may state they design around 23mm tires, but that doesn't really address which tire is most aerodynamic.


True. But at least in what I've seen publicly available, I've never been all that impressed by *anything* with narrow (<22m) tires. Even the HED3. (ignoring the watts-to-spin). I've heard several claim they've done personal testing, or testing they can't release. I just haven't seen it.


Why would you ignore watts to spin? ;-)

I don't have any idea what it takes to impress you, but when you are trying to squeeze blood out of a turnip, a single drop is miraculous!

here's some publicly available data regarding tire width:



http://biketechreview.com/...ce-of-tire-selection

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Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
=================
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Re: Aerodynamic Hierarchy [BikeTechReview] [ In reply to ]
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BikeTechReview wrote:
I think what reigns true is that a narrow, well-shaped, low crr tire is needed in the market.
I just want to echo this. I do like wider tires for a lot of things, but we still need a good narrow, well-shaped, low crr tire.
The 2016 20mm supersonic still fit that bill, but the 2017 version does not, which leaves us with pretty much nothing, so things are getting worse not better.
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Re: Aerodynamic Hierarchy [BikeTechReview] [ In reply to ]
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BikeTechReview wrote:
Why would you ignore watts to spin? ;-)

Same reason. Lack of good public data. I think Josh Poertner did a good job of relating his experiences with Watts-to-spin. But that's the only thing I remember off the top of my head. For the life of me I don't know why HED doesn't explicitly advertise their own testing on watts-to-spin. In fact all aero graphs seem to be gone from the HED Web site, which is unfortunate.


Quote:
here's some publicly available data regarding tire width:

Those older rims were designed in the days when 23mm was considered really wide, so it's not surprising they'd perform better with narrower tires vs. 25mm

The Flo tire study shows that at least on their really wide rims the 25mm GP4000SII performs identically 22m Attack with combined Crr/CdA. [Interactive graph here] And the 23mm Supersonic wins out over everything.
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Re: Aerodynamic Hierarchy [trail] [ In reply to ]
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trail wrote:
BikeTechReview wrote:

Why would you ignore watts to spin? ;-)


Same reason. Lack of good public data. <snip>

...cool - love the skepticism. I'm cut from the same vein - and also love taking the extra steps to explore things deeper into the weeds. Funny anecdote regarding that self funded A&M test back in 2003 - one of the reasons I tested those tires was because there was a lot of buzz at the time about how the Zipp product (due to their hed/zipp 1.05 patent) was more robust to tire width than the rest of their competitors. Turns out that that buzz might not have been founded in reality. <shrug>

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Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
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Re: Aerodynamic Hierarchy [lanierb] [ In reply to ]
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lanierb wrote:
BikeTechReview wrote:

I think what reigns true is that a narrow, well-shaped, low crr tire is needed in the market.

I just want to echo this. I do like wider tires for a lot of things, but we still need a good narrow, well-shaped, low crr tire.
The 2016 20mm supersonic still fit that bill, but the 2017 version does not, which leaves us with pretty much nothing, so things are getting worse not better.

yay! I'm not alone! haha! :-)

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Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
=================
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