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

Cross-Manufacturer Aero Bike Comparison (S3 vs S5 vs Venge)

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

Cross-Manufacturer Aero Bike Comparison (S3 vs S5 vs Venge)

Old 10-11-11, 10:55 AM
  #1  
RecceDG
Token Canadian
Thread Starter
 
RecceDG's Avatar
 
Join Date: Nov 2008
Location: Gagetown, New Brunswick
Posts: 1,555

Bikes: Cervelo S1, Norco Faze 1 SL, Surly Big Dummy, Moose Fatbike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 200 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Cross-Manufacturer Aero Bike Comparison (S3 vs S5 vs Venge)

To review other discussion on aero bikes:

- Per the scientific literature, the drag on the bike is responsible for about 35% of the total aero drag. That percentage will vary somewhat depending on the size and shape of the rider, but as a rule of thumb, it is a decent estimate.

- This percentage is large enough that, keeping the rider constant, improvements to the aero drag of the bike will pay performance dividends for that rider; either in terms of an increase in top speed for the same wattage, or a reduction in wattage for the same speed.

- Unlike weight - which is easily verifiable through direct measurement - measuring and verifying drag claims is difficult to do. It is subject to a large number of variables and no small amount of placebo effect. Add to this that improvements, while significant, are typically small enough in absolute magnitude that it may be tough to separate signal from noise.

- Manufacturers tend not to release raw test data, and published comparisons tend to be within their own product line, rather than against competitor's bikes. Thus, we know from Cervelo's literature that the S5 is better than the S3 (and by roughly how much) but they don't talk about S5 vs Venge (or whatever).

Well I found an interesting data point in a Peleton magazine review of the latest Venge, in which a Specialized engineer states that they tested a Venge against an S3, and that the Venge had an aero profile "essentially identical" to the S3.

"Essentially identical" I parse as "slightly inferior to, but to an insignificant degree" because if the Venge had been the tiniest bit better, he would have stated "slightly better" (or similar)

He also mentioned that the McLearen partnership was not about aero, but rather about carbon layup techniques.

DG
RecceDG is offline  
Old 10-11-11, 12:10 PM
  #2  
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Posts: 7,934

Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 379 Post(s)
Liked 15 Times in 12 Posts
Interesting; I didn't realise the bike was 35% of it... I guess I'd assumed more in the neighbourhood of 20%.

But I guess it's a more turbulence-prone shape than a rider, even if most of the machine is along the axis of travel.
Kimmo is offline  
Old 10-11-11, 12:15 PM
  #3  
ColinL
Two-Wheeled Aficionado
 
ColinL's Avatar
 
Join Date: Jul 2011
Location: Wichita
Posts: 4,903

Bikes: Santa Cruz Blur TR, Cannondale Quick CX dropbar conversion & others

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I can believe it, if the weighting assumes rider's position and his equipment is as aero as possible.

This is not typical BF member out for a spin.. in that case I disbelieve the bike would ever be as high as 35%.
ColinL is offline  
Old 10-11-11, 12:43 PM
  #4  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 19,068
Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 7971 Post(s)
Liked 184 Times in 121 Posts
Don't get too caught up with the percent. How much of the pie the bike is responsible for is going to change when the other stuff (rider and wheels) change. The OP was only shooting for a fair estimate.
Seattle Forrest is offline  
Old 10-11-11, 12:58 PM
  #5  
guadzilla
Dropped again
 
guadzilla's Avatar
 
Join Date: Feb 2009
Location: A small tropical island
Posts: 3,459

Bikes: Damocles, Shiv, Lynskey, X-Fire, LHT, +

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The question is, how do these aero bikes handle in terms of stiffness and "jump"?

I want to get me an aero road bike - but I want a bike that feels lively and accelerates instantly when I stomp on the pedals. My Damocles does that - my Excalibur didnt (which is why I sold it)... I dont labor under the misconception that this affects performance, but it does affect how the bike feels. And I like them stiff (that's what she said).

The Foil is another bike that made it to my list b/c of its emphasis not just on aero but also stiffness. I have also read in a few articles that some aero bikes feel dead - but those articles didnt mention which ones.
guadzilla is offline  
Old 10-11-11, 12:59 PM
  #6  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 19,068
Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 7971 Post(s)
Liked 184 Times in 121 Posts
^ You had a sword of Damocles?
Seattle Forrest is offline  
Old 10-11-11, 01:22 PM
  #7  
RecceDG
Token Canadian
Thread Starter
 
RecceDG's Avatar
 
Join Date: Nov 2008
Location: Gagetown, New Brunswick
Posts: 1,555

Bikes: Cervelo S1, Norco Faze 1 SL, Surly Big Dummy, Moose Fatbike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 200 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I can believe it, if the weighting assumes rider's position and his equipment is as aero as possible.

This is not typical BF member out for a spin.. in that case I disbelieve the bike would ever be as high as 35%.
The paper examined a number of different equipment combinations and rider positions and determined that the drag effects from various combinations were effectively additive. They then worked out a multiplicative coefficiant for each sub-assembly that could be used to fairly high accuracy to estimate the likely change in drag.

So for example, a round-tube frame, wire spoked, box section rims, rider wearing normal kit and a regular helmet, on the hoods might have a coefficant of "1" per sub-assembly. The aero frame might be 0.92, bladed spokes 0.98, aero rims 0.96, skinsuit 0.98, aero helmet 0.94, on the drops 0.94 (I'm making these numbers up) and by summing coefficients you get the total change in drag.

It was actually a surprise to see that all these sub-assemblies were additive, because that implies that there's little to no interaction between sub-assemblies... but that's what their tests showed.

When you consider this method, it means that the only thing that would really change the initial percentage would be the change in frontal area between their test rider and the sample person. The final percentage would be that plus all the changes to coefficients (which could go up or down depending)

I have no problem believing my personal bike percentage is lower than 35%, because I have a fairly robust frontal area and an aero bike. But I bet it is closer to 30% than 10% - there's a lot of bike exposed to the air stream.

DG
RecceDG is offline  
Old 10-11-11, 01:52 PM
  #8  
Fiery
Senior Member
 
Fiery's Avatar
 
Join Date: Oct 2010
Posts: 1,314
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 218 Post(s)
Liked 0 Times in 0 Posts
Originally Posted by Seattle Forrest View Post
Don't get too caught up with the percent. How much of the pie the bike is responsible for is going to change when the other stuff (rider and wheels) change. The OP was only shooting for a fair estimate.
The bike might account for 35% of the drag, but it doesn't account for 35% of the possible improvements. How much improvement is is possible to get on an aero frame nowadays? Several percent at best, and that doesn't get you more than one or two percent off the total drag. On the other hand, differing riding positions can produce a much greater net effect on the overall drag.
Fiery is offline  
Old 10-11-11, 02:31 PM
  #9  
RecceDG
Token Canadian
Thread Starter
 
RecceDG's Avatar
 
Join Date: Nov 2008
Location: Gagetown, New Brunswick
Posts: 1,555

Bikes: Cervelo S1, Norco Faze 1 SL, Surly Big Dummy, Moose Fatbike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 200 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
On the other hand, differing riding positions can produce a much greater net effect on the overall drag.
At the same time though, that's not a zero-sum game; you can reduce bike drag AND position drag at the same time.

Or put another way, if your position drag has already been minimized/optimized, the only way to further reduce it is through optimizations on the bike itself.

And while the gains from optimizing the bike may seem to be small, humans - even elite athletes - just aren't all that powerful. We just don't produce enough wattage to be able to ignore the effects of small changes to drag. What may seem like a trivial savings - would be a trivial savings in a motor-powered application - is decidedly non-trivial in a human-powered application.

Finally, if I recall correctly (I don't have the study here in front of me to double-check) the measured difference in drag between a round-tube frame and an "aero frame" made as much difference to total drag as moving from the hoods to aerobars. That I found astounding, and I wish there had been more data about which aero frame they were measuring (Lotus Superbike?) But it would appear that there is far more to an aero frame than what one intuitively expects.

Air is weird that way.

DG
RecceDG is offline  
Old 10-11-11, 02:51 PM
  #10  
Bacciagalupe
Professional Fuss-Budget
 
Bacciagalupe's Avatar
 
Join Date: Aug 2005
Posts: 6,472
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Cervelo claims that the S5 is ~37s seconds faster than an S3 over 40km, if you're riding at 40kph. Under ideal conditions.

That's a 1% improvement, which does make me curious as to the margin of error of their testing methodology.

I would say "a difference along those lines is only important to a top pro," except that professionals on non-aero bikes have repeatedly beaten other pros on aero bikes to the line, time after time after time.

As such, I'm a bit skeptical of the benefits of aero bikes in general, let alone one aero bike vs another.
Bacciagalupe is offline  
Old 10-11-11, 03:02 PM
  #11  
ColinL
Two-Wheeled Aficionado
 
ColinL's Avatar
 
Join Date: Jul 2011
Location: Wichita
Posts: 4,903

Bikes: Santa Cruz Blur TR, Cannondale Quick CX dropbar conversion & others

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
It was interesting to me was when Tyler Farrar winning a sprint stage in the 2011 TdF on a R3. I have no clue if he didn't have enough time to get comfortable on the S5 or what.

No one goes out for a time trial on a non-aero bike though.
ColinL is offline  
Old 10-11-11, 03:03 PM
  #12  
eminefes
Senior Member
 
Join Date: May 2008
Posts: 409
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by RecceDG View Post
Finally, if I recall correctly (I don't have the study here in front of me to double-check) the measured difference in drag between a round-tube frame and an "aero frame" made as much difference to total drag as moving from the hoods to aerobars.
So all those guys I see with aerobars just need to buy an S5 or Venge and they can finally ride on the hoods without any loss of speed.

Yeah, I don't believe that for a second.
eminefes is offline  
Old 10-11-11, 03:48 PM
  #13  
ilovecycling
Senior Member
 
Join Date: Dec 2010
Location: RTP, NC
Posts: 2,190

Bikes: LOOK 595 & Cannondale CAAD9

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Bacciagalupe View Post
Cervelo claims that the S5 is ~37s seconds faster than an S3 over 40km, if you're riding at 40kph. Under ideal conditions.

That's a 1% improvement, which does make me curious as to the margin of error of their testing methodology.

I would say "a difference along those lines is only important to a top pro," except that professionals on non-aero bikes have repeatedly beaten other pros on aero bikes to the line, time after time after time.

As such, I'm a bit skeptical of the benefits of aero bikes in general, let alone one aero bike vs another.
If you are going 40kph on both bikes, how would one bike be 37 seconds faster? They would need to make that claim for a constant power output in Watts for that to make any sense. Example: At a constant 250 Watts over 40km the S5 is 37 seconds faster.

I've said this around here before, but I'll say it again: Aero road bikes are nonsense. There are too many variables and dynamics in a bicycle race for that 37 second aero advantage to actually come into play. Road racing is a strategic game where breakaways are countered by chases. It's not a situation where every racer goes 100% from start to finish under ideal conditions and stays in their own head trying to break their own personal record. TTs are a different story because you are racing against the clock, but even then the rider position and other variables are going to matter much more than the shape of the tubes on the bike.

Even for a "top pro" there is no significant advantage. You can throw all the scientific facts my way and it still means jack **** in the real world.
ilovecycling is offline  
Old 10-11-11, 03:59 PM
  #14  
asgelle
Senior Member
 
Join Date: Apr 2006
Location: Albuquerque, NM
Posts: 3,683
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 379 Post(s)
Liked 15 Times in 8 Posts
Originally Posted by Bacciagalupe View Post
I would say "a difference along those lines is only important to a top pro," except that professionals on non-aero bikes have repeatedly beaten other pros on aero bikes to the line, time after time after time.
Look at it this way. Cycling speed is a balance between the supply (power produced by the rider) and demand (power lost to drag, rolling resistance, gravity etc.) Although raising supply and lowering demand isn't precisely symmetric, it's pretty close. So if an aero bike lowers the power demand by 5-10 W, that's pretty close to increasing the rider's power by the same amount. First, who wouldn't want an extra 5-10 W of power if it were available, and second, it takes an awful lot of hard training for an experience rider to improve by that amount. So it isn't only the top pro who should look for this benefit, but anyone who is sacrificing and suffering in training to wring an extra few Watts of power out of their body demonstrates that it is important to them.
asgelle is offline  
Old 10-11-11, 04:31 PM
  #15  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 19,068
Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 7971 Post(s)
Liked 184 Times in 121 Posts
Originally Posted by RecceDG View Post
Or put another way, if your position drag has already been minimized/optimized, the only way to further reduce it is through optimizations on the bike itself.
You're probably counting the wheels as part of the bike. I've been told that the wheels have about the same share of the pie as the bike (frameset) in terms of aerodynamic drag. I have no way of knowing whether that's true or not. Can anyone shed some light on this?
Seattle Forrest is offline  
Old 10-11-11, 04:34 PM
  #16  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 19,068
Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 7971 Post(s)
Liked 184 Times in 121 Posts
This thread gives me an opportunity to dig up some vintage photos from an article Saint Sheldon's site, titled "Measuring Aerodynamic Drag."

Seattle Forrest is offline  
Old 10-11-11, 06:24 PM
  #17  
RecceDG
Token Canadian
Thread Starter
 
RecceDG's Avatar
 
Join Date: Nov 2008
Location: Gagetown, New Brunswick
Posts: 1,555

Bikes: Cervelo S1, Norco Faze 1 SL, Surly Big Dummy, Moose Fatbike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 200 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Even for a "top pro" there is no significant advantage.
But then you get things like Thor's massive come-from-behind rundown of the break for the stage win in this year's TdF - on an S5.

True enough, a huge part of that performance is because he's Thor Friggin' Hushvold. No random Fred is going to be able to throw down that performance just because he's on an S5. But maybe the difference between that move working the way it did, and Thor not running down the break, is the better aero of the bike.

There's no way for us to know. I'm not sure if *Thor* knows - and it's not like we can ask him to try again with different equipment.

Correlation does not prove causation - but lacking correlation disproves causation.

DG
RecceDG is offline  
Old 10-11-11, 08:04 PM
  #18  
ilovecycling
Senior Member
 
Join Date: Dec 2010
Location: RTP, NC
Posts: 2,190

Bikes: LOOK 595 & Cannondale CAAD9

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by RecceDG View Post
But then you get things like Thor's massive come-from-behind rundown of the break for the stage win in this year's TdF - on an S5.

True enough, a huge part of that performance is because he's Thor Friggin' Hushvold. No random Fred is going to be able to throw down that performance just because he's on an S5. But maybe the difference between that move working the way it did, and Thor not running down the break, is the better aero of the bike.

There's no way for us to know. I'm not sure if *Thor* knows - and it's not like we can ask him to try again with different equipment.

Correlation does not prove causation - but lacking correlation disproves causation.

DG
I understand where you're coming from, but even Thor knows he won that stage because of what was inside him and not what he was riding. It just isn't about the bike no matter what these companies are trying to trick us into believing.

Last edited by ilovecycling; 10-11-11 at 08:08 PM.
ilovecycling is offline  
Old 10-11-11, 08:16 PM
  #19  
Minion1
Senior Member
 
Join Date: Apr 2011
Posts: 548
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by RecceDG View Post
But then you get things like Thor's massive come-from-behind rundown of the break for the stage win in this year's TdF - on an S5.

True enough, a huge part of that performance is because he's Thor Friggin' Hushvold. No random Fred is going to be able to throw down that performance just because he's on an S5. But maybe the difference between that move working the way it did, and Thor not running down the break, is the better aero of the bike.

There's no way for us to know. I'm not sure if *Thor* knows - and it's not like we can ask him to try again with different equipment.

Correlation does not prove causation - but lacking correlation disproves causation.

DG
Maybe Tommy Voekler's lugged Colnago is more aero than we think.
Minion1 is offline  
Old 10-11-11, 08:32 PM
  #20  
I <3 Robots
Senior Member
 
I <3 Robots's Avatar
 
Join Date: Apr 2010
Location: So Cal
Posts: 1,657

Bikes: Cervelo S2, Workswell 062, Banshee Spitfire

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thor was going to win that stage no matter what.

Cervelo loves to throw number out. Numbers that the average Cervelo buyer will not likely ever test.

I saw an S5 last weekend...it had 40mm's of spacers and the stem was turned up.
I <3 Robots is offline  
Old 10-12-11, 02:59 AM
  #21  
WHOOOSSHHH...
Senior Member
 
WHOOOSSHHH...'s Avatar
 
Join Date: Aug 2007
Location: RVA
Posts: 6,404
Mentioned: 2 Post(s)
Tagged: 1 Thread(s)
Quoted: 24 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by I <3 Robots View Post
I saw an S5 last weekend...it had 40mm's of spacers.. .
I agree with you....I have a venge and was running no spacers with a -10 degree pro Vibe stem 120mm. was not comfortable. Added spacers and a -6 degree
3T stem...Kind of defeated the purpose....
WHOOOSSHHH... is offline  
Old 10-12-11, 04:05 AM
  #22  
guadzilla
Dropped again
 
guadzilla's Avatar
 
Join Date: Feb 2009
Location: A small tropical island
Posts: 3,459

Bikes: Damocles, Shiv, Lynskey, X-Fire, LHT, +

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Seattle Forrest View Post
^ You had a sword of Damocles?
Yeah, i lost my head while shopping.
guadzilla is offline  
Old 10-12-11, 04:09 AM
  #23  
guadzilla
Dropped again
 
guadzilla's Avatar
 
Join Date: Feb 2009
Location: A small tropical island
Posts: 3,459

Bikes: Damocles, Shiv, Lynskey, X-Fire, LHT, +

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by ilovecycling View Post
I've said this around here before, but I'll say it again: Aero road bikes are nonsense. There are too many variables and dynamics in a bicycle race for that 37 second aero advantage to actually come into play. Road racing is a strategic game where breakaways are countered by chases. It's not a situation where every racer goes 100% from start to finish under ideal conditions and stays in their own head trying to break their own personal record.
That doesnt make the aero advantage of the bike "nonsense". People go off the front. Others, like me, specialize in bringing the rear. From way, way back. Besides, applying your logic, we dont need deep section wheels either. Do you go around posting that they are useless as well?

You can throw all the scientific facts my way and it still means jack **** in the real world.
So fine. Presumably, others can - and do - feel differently.
guadzilla is offline  
Old 10-12-11, 04:55 AM
  #24  
MajorMantra
Senior Member
 
MajorMantra's Avatar
 
Join Date: Jan 2009
Location: Bristol, UK
Posts: 1,136
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by ColinL View Post
It was interesting to me was when Tyler Farrar winning a sprint stage in the 2011 TdF on a R3. I have no clue if he didn't have enough time to get comfortable on the S5 or what.

No one goes out for a time trial on a non-aero bike though.
Ahem.




http://www.bikeradar.com/news/articl...e-bikes-31480/


Of course this wasn't a completely typical TT.
MajorMantra is offline  
Old 10-12-11, 04:58 AM
  #25  
RecceDG
Token Canadian
Thread Starter
 
RecceDG's Avatar
 
Join Date: Nov 2008
Location: Gagetown, New Brunswick
Posts: 1,555

Bikes: Cervelo S1, Norco Faze 1 SL, Surly Big Dummy, Moose Fatbike

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 200 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Maybe Tommy Voekler's lugged Colnago is more aero than we think.
Or maybe if he'd been on an aero bike he would have saved enough energy to keep yellow all the way to Paris.

Thor was going to win that stage no matter what.
That was by no means a given. Only Thor knows how close to the ragged edge that effort took him.

There's no way to definitively *know* the answer here, to either of these questions/postulations. There are so many other variables it is nearly impossible to nail down if the use or lack of an aero bike was the deciding factor.

What IS clear is that aero bikes go significantly faster for the same wattage expended. That's an advantage no matter who you are. It may or may not be the decisive advantage, but it is an advantage nonetheless.

DG
RecceDG is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.