Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

Aero frame tubes just ain't all that...

Notices
Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Aero frame tubes just ain't all that...

Old 01-14-14, 11:15 AM
  #1  
Campag4life
Voice of the Industry
Thread Starter
 
Campag4life's Avatar
 
Join Date: May 2007
Posts: 12,572
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1187 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Aero frame tubes just ain't all that...

Proof is in the following video which is also quite entertaining.
https://www.youtube.com/watch?v=Mh0y6S5HTtc

I won't give it away but see it through to the end and you may be a bit surprised as I was.

Bottom line is rider position on the bike trumps tube shape for speed...what many already know.
Campag4life is offline  
Old 01-14-14, 11:27 AM
  #2  
canam73
Senior Member
 
Join Date: Jun 2007
Location: Haunchyville
Posts: 6,400
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked 5 Times in 2 Posts
Are they really ranking bikes off of 1 rider, 1 run, no mention of equalizing wheels, tires or psi and admittedly setting the handle bar heights differently?
canam73 is offline  
Old 01-14-14, 11:33 AM
  #3  
RJM
I'm doing it wrong.
 
RJM's Avatar
 
Join Date: Jun 2009
Posts: 4,875

Bikes: Rivendell Appaloosa, Rivendell Frank Jones Sr., Trek Fuel EX9, Kona Jake the Snake CR, Niner Sir9

Mentioned: 80 Post(s)
Tagged: 0 Thread(s)
Quoted: 8746 Post(s)
Liked 1,938 Times in 1,164 Posts
Originally Posted by Campag4life View Post
Proof is in the following video which is also quite entertaining.
https://www.youtube.com/watch?v=Mh0y6S5HTtc

I won't give it away but see it through to the end and you may be a bit surprised as I was.

Bottom line is rider position on the bike trumps tube shape for speed...what many already know.
Sure, that makes total sense. The rider's body is a much larger portion of the bike/rider hitting the wind.
RJM is offline  
Old 01-14-14, 11:38 AM
  #4  
Campag4life
Voice of the Industry
Thread Starter
 
Campag4life's Avatar
 
Join Date: May 2007
Posts: 12,572
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1187 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Originally Posted by canam73 View Post
Are they really ranking bikes off of 1 rider, 1 run, no mention of equalizing wheels, tires or psi and admittedly setting the handle bar heights differently?
Are you? Point is the difference between all the bikes tested is 'noise'...nebula...nada. Mostly riding position dictates aerodynamics versus the air cutting quality of tapered tube sections on a bicycle frame.
Virtually nobody here is going see much if any difference between the performance of the bikes tested.
Campag4life is offline  
Old 01-14-14, 11:49 AM
  #5  
canam73
Senior Member
 
Join Date: Jun 2007
Location: Haunchyville
Posts: 6,400
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked 5 Times in 2 Posts
Originally Posted by Campag4life View Post
Are you? Point is the difference between all the bikes tested is 'noise'...nebula...nada. Mostly riding position dictates aerodynamics versus the air cutting quality of tapered tube sections on a bicycle frame.
Virtually nobody here is going see much if any difference between the performance of the bikes tested.
I got your point. But you didn't make what is apparently a running series of tests with high profile bike companies top bikes shown in a ranking down to a fraction of a second. Yes, they mention the head tube difference, but that is only at the end. It takes an seasoned, observant BFer such as yourself to catch it.
canam73 is offline  
Old 01-14-14, 12:01 PM
  #6  
shoota 
Senior Member
 
shoota's Avatar
 
Join Date: Jun 2012
Location: Stillwater, OK
Posts: 7,381
Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 1506 Post(s)
Liked 314 Times in 227 Posts
That might the most un-scientific test ever.
__________________
2014 Cannondale SuperSix EVO 2
2019 Salsa Warbird
shoota is offline  
Old 01-14-14, 12:03 PM
  #7  
gus6464
Senior Member
 
Join Date: Jan 2010
Location: San Diego
Posts: 2,235
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 353 Post(s)
Likes: 0
Liked 91 Times in 66 Posts
If anything I would think the smallest and thinnest bike frame would be most aerodynamic since it equates to a smaller area of wind resistance.
gus6464 is offline  
Old 01-14-14, 12:05 PM
  #8  
Campag4life
Voice of the Industry
Thread Starter
 
Campag4life's Avatar
 
Join Date: May 2007
Posts: 12,572
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1187 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Originally Posted by canam73 View Post
I got your point. But you didn't make what is apparently a running series of tests with high profile bike companies top bikes shown in a ranking down to a fraction of a second. Yes, they mention the head tube difference, but that is only at the end. It takes an seasoned, observant BFer such as yourself to catch it.
Yes there are clearly many factors including Mr. H's varied aka undialed position on each bike. No doubt he is able to power some bikes better than others based upon his snap shot fit. So yes, the test is flawed. But what is does expose with all the variability subtracting reliability of the test format is just how close the bikes are together and at the end of the day the bike with the fattest non aero tube sections won the downhill.
Largely entertaining and non scientific but bottom line is there isn't a lot of difference between those bikes tested...especially say between the Venge and Tarmac and most concede the Tarmac is a better climbing bike, lighter and with a best ride quality.
Campag4life is offline  
Old 01-14-14, 12:07 PM
  #9  
Campag4life
Voice of the Industry
Thread Starter
 
Campag4life's Avatar
 
Join Date: May 2007
Posts: 12,572
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1187 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Originally Posted by gus6464 View Post
If anything I would think the smallest and thinnest bike frame would be most aerodynamic since it equates to a smaller area of wind resistance.
The hole the rider punches in the air >>>>frame tube size/profile when it comes to aerodynamics. In a wind tunnel size to size the S5 is the most aerodynamic bike in the test. The dogma had a shorter headtube and lower rider position and hence a smaller hole punched in the wind for less resistance.
Campag4life is offline  
Old 01-14-14, 12:57 PM
  #10  
Looigi
Senior Member
 
Looigi's Avatar
 
Join Date: Dec 2010
Posts: 8,951
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 14 Post(s)
Likes: 0
Liked 9 Times in 8 Posts
Actually, considering all the variables that weren't controlled for, I'm quite surprised the times were as close as they were.

Shoot, you'd think they would have at least done multiple runs in each configuration.
Looigi is offline  
Old 01-14-14, 01:28 PM
  #11  
Wesley36
Senior Member
 
Wesley36's Avatar
 
Join Date: Jul 2009
Posts: 1,001
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Marginal gains are marginal. Rider position trumps pretty much everything, but even still, tight jerseys, aero wheels and aero frames make some difference.

Last edited by Wesley36; 01-14-14 at 02:02 PM.
Wesley36 is offline  
Old 01-14-14, 01:52 PM
  #12  
Campag4life
Voice of the Industry
Thread Starter
 
Campag4life's Avatar
 
Join Date: May 2007
Posts: 12,572
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1187 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Originally Posted by Looigi View Post
Actually, considering all the variables that weren't controlled for, I'm quite surprised the times were as close as they were.

Shoot, you'd think they would have at least done multiple runs in each configuration.
In bold...I believe is the signature take away.
As to multiple runs....hmmm...maybe Mr. H is superstitious and didn't want to hedge his bets about flatting.
Campag4life is offline  
Old 01-14-14, 02:07 PM
  #13  
lsberrios1 
Senior Member
 
lsberrios1's Avatar
 
Join Date: Jul 2012
Location: Atlanta GA
Posts: 2,844

Bikes: '13 Spech Roubaix SL4 Expert

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 297 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I wonder if bicycle companies take into the effect that the difference in rider shape can affect the aero effects of their bikes. I think aero bikes should be optimized to deflect air from the rider instead of looking which frame cuts better through the wind. I belive that bikes could be used as some sort of windshield for the rider since bikes don't ride themselves. Of course this all is dependent on shape of rider and position. In essence there is no better aero than no resistance at all, hence nothing. but when you have something behind of nothing that something becomes the un aero feature. By adding a wind deflector (bike) resistance can be lowered if the bike is shaped for it. I am sure that if you place a bike alone on a wind tunel it would do better if it had no motorcycle-like windshield, but if you put a rider on it, it would be better with the motorcycle like windshield. Then weight would be sacrificed.
__________________
Cat 6 going on PRO....
lsberrios1 is offline  
Old 01-14-14, 02:11 PM
  #14  
link0
Senior Member
 
link0's Avatar
 
Join Date: Jun 2013
Location: Los Angeles
Posts: 794

Bikes: '11 Merlin Extralight, '98 Dean Castanza, '89 Schwinn Prologue

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Although entertaining to watch, that video shows absolutely NOTHING. No variables were kept constant.
link0 is offline  
Old 01-14-14, 02:17 PM
  #15  
Jakedatc
Senior Member
 
Jakedatc's Avatar
 
Join Date: Oct 2007
Location: CT
Posts: 3,054
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 9 Times in 6 Posts
Stupid attempt to be like Top Gear. even worse than Top Gear US. whatever else.. who cares.
Jakedatc is offline  
Old 01-14-14, 02:18 PM
  #16  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,322 Times in 832 Posts
If you get there first , Top of the podium, atribute it to what you rode to get there If you wish.

the Bike Companies' sales campaigns will want you to think so.. shop away Lads.
fietsbob is offline  
Old 01-14-14, 02:22 PM
  #17  
Campag4life
Voice of the Industry
Thread Starter
 
Campag4life's Avatar
 
Join Date: May 2007
Posts: 12,572
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1187 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Originally Posted by link0 View Post
Although entertaining to watch, that video shows absolutely NOTHING. No variables were kept constant.
You don't get it. You saw nothing but others more astute like Looigi did...lol.
Campag4life is offline  
Old 01-14-14, 02:23 PM
  #18  
Campag4life
Voice of the Industry
Thread Starter
 
Campag4life's Avatar
 
Join Date: May 2007
Posts: 12,572
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1187 Post(s)
Likes: 0
Liked 6 Times in 6 Posts
Originally Posted by Jakedatc View Post
Stupid attempt to be like Top Gear. even worse than Top Gear US. whatever else.. who cares.
I bet you're fun at parties.
Campag4life is offline  
Old 01-14-14, 02:25 PM
  #19  
Wesley36
Senior Member
 
Wesley36's Avatar
 
Join Date: Jul 2009
Posts: 1,001
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by lsberrios1 View Post
I wonder if bicycle companies take into the effect that the difference in rider shape can affect the aero effects of their bikes.
Yes, Cervelo uses a dummy modeled on Dave Zabriskie

Attached Images
File Type: jpg
28679-medium_test9.jpg (14.0 KB, 16 views)
Wesley36 is offline  
Old 01-14-14, 02:27 PM
  #20  
wphamilton
Senior Member
 
wphamilton's Avatar
 
Join Date: Apr 2011
Location: Alpharetta, GA
Posts: 15,280

Bikes: Nashbar Road

Mentioned: 71 Post(s)
Tagged: 0 Thread(s)
Quoted: 2932 Post(s)
Liked 333 Times in 223 Posts
Originally Posted by gus6464 View Post
If anything I would think the smallest and thinnest bike frame would be most aerodynamic since it equates to a smaller area of wind resistance.
That is a very reasonable surmise and it's not clearly wrong. In most of the possible comparisons between frames, I'm guessing that it's accurate. Yet, I've seen enough data from different tests to convince me that, at least in some cases, the aero-shaped frame has an aerodynamic advantage over a same-sized thinner round-tube frame. Even so I have to question a lot of the assumptions about aero frame shape.

One, I don't believe that head tube and downtube cross sections are truly that aero in shape. They have the appearance, but they aren't actually long enough (front to back side of the tube) for the lower-drag shapes, in other words tapering too quickly. Second, if you draw the shape on paper and visualize different apparent wind angles, at some point not very far from dead on the aero tube shape loses all advantage, and is possibly worse than a simple cylinder. Third, it's not really a static system in that the streamlines (where there are streamlines) depend not only on the immediate surface and shape but also on what the air is doing in nearby areas. And finally, how much does it depend on how you're riding a particular bike, even if you have the exact same position on each? Rocking it back and forth or steady on the rivet, how often you gun it hard, how you attack the corners and what line, maybe these (and other differences I'm not thinking of) depend on how the bike responds and maybe that also affects the aerodynamics? I think that's probably true.

On the other side, there's something about the frame transitional points, like where the head tube meets the top tube, behind the seat tube, other places. If some frames test out more aero than others, I think - and this is just a surmise - that it's in large part if not entirely due to smoothing out the air flow at these places. So there may be something there.
wphamilton is offline  
Old 01-14-14, 02:29 PM
  #21  
lsberrios1 
Senior Member
 
lsberrios1's Avatar
 
Join Date: Jul 2012
Location: Atlanta GA
Posts: 2,844

Bikes: '13 Spech Roubaix SL4 Expert

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 297 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Wesley36 View Post
Yes, Cervelo uses a dummy modeled on Dave Zabriskie

Thanks for the clarification. So the next logical step is to buy a bicycle based on the person the company modeled the bike after.
__________________
Cat 6 going on PRO....
lsberrios1 is offline  
Old 01-14-14, 02:31 PM
  #22  
donrhummy
Senior Member
 
donrhummy's Avatar
 
Join Date: Dec 2005
Posts: 3,481
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Campag4life View Post
Proof is in the following video which is also quite entertaining.
https://www.youtube.com/watch?v=Mh0y6S5HTtc

I won't give it away but see it through to the end and you may be a bit surprised as I was.

Bottom line is rider position on the bike trumps tube shape for speed...what many already know.
This is not even a little bit scientific and tells you nothing. Some of the MANY variables it ignores:

1. Speed and direction of the wind on each of those days

2. The exact watts he put out at every point of each ride

3. The exact angles, lines he took when going downhill

4. His weight for each ride (a person's weight can differ by 5 pounds)

5. The other components on each of the frames (wheels/tires have the biggest impact)
donrhummy is offline  
Old 01-14-14, 02:37 PM
  #23  
JasonCarp
Senior Member
 
JasonCarp's Avatar
 
Join Date: Sep 2011
Location: Grand Rapids, MI
Posts: 129

Bikes: Specialized Cross Trail, Specialized Roubaix, Paramount PDG 5, Framed Alaskan Carbon, BMC Roadmachine 01

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I am betting at just over 200 lbs right now, my gravitational pull would put me under 2:00.0 on either of those bikes.
JasonCarp is offline  
Old 01-14-14, 03:54 PM
  #24  
hueyhoolihan
Senior Member
 
Join Date: Dec 2010
Location: Above ground, Walnut Creek, Ca
Posts: 6,681

Bikes: 8 ss bikes, 1 5-speed touring bike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by lsberrios1 View Post
I wonder if bicycle companies take into the effect that the difference in rider shape can affect the aero effects of their bikes. I think aero bikes should be optimized to deflect air from the rider instead of looking which frame cuts better through the wind. I belive that bikes could be used as some sort of windshield for the rider since bikes don't ride themselves. Of course this all is dependent on shape of rider and position. In essence there is no better aero than no resistance at all, hence nothing. but when you have something behind of nothing that something becomes the un aero feature. By adding a wind deflector (bike) resistance can be lowered if the bike is shaped for it. I am sure that if you place a bike alone on a wind tunel it would do better if it had no motorcycle-like windshield, but if you put a rider on it, it would be better with the motorcycle like windshield. Then weight would be sacrificed.
you make a good point.
hueyhoolihan is offline  
Old 01-14-14, 03:57 PM
  #25  
Jakedatc
Senior Member
 
Jakedatc's Avatar
 
Join Date: Oct 2007
Location: CT
Posts: 3,054
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 9 Times in 6 Posts
Originally Posted by lsberrios1 View Post
I wonder if bicycle companies take into the effect that the difference in rider shape can affect the aero effects of their bikes. I think aero bikes should be optimized to deflect air from the rider instead of looking which frame cuts better through the wind. I belive that bikes could be used as some sort of windshield for the rider since bikes don't ride themselves. Of course this all is dependent on shape of rider and position. In essence there is no better aero than no resistance at all, hence nothing. but when you have something behind of nothing that something becomes the un aero feature. By adding a wind deflector (bike) resistance can be lowered if the bike is shaped for it. I am sure that if you place a bike alone on a wind tunel it would do better if it had no motorcycle-like windshield, but if you put a rider on it, it would be better with the motorcycle like windshield. Then weight would be sacrificed.
Except that it is against UCI regulations to have anything resembling a fairing. which is what you are talking about.
Jakedatc is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.