TOUR MAG AERO TEST 2016

[Epic-o]

How many amateur riders that you know have lost a race because their frame was not aero enough? How many trainers that you know tell you "if you want to be faster you better buy an aero frame"?

I find quite amusing that an adult person employs so much other's decisions/opinions to justify his arguments. I would rather use physics to guide my choices regarding equipment, particularly due to the problems related to perception. A quite interesting read about this from Josh Poertner, ex-Zipp engineer:

"I don't know anything about your fit other than the 110 stem (which Aaron is right, 110 would have meant that frame was way too big for you 20 years ago as we all had 120-130s), but from experience I might guess that part of the liveliness you feel in that bike is because of it's relatively small size compared to the others you're riding. A more compact frame can have different stiffness/damping characteristics that make it feel 'livelier' than a larger one, but even moreso, I'm a strong believer in the mental aspect of the small bike. My personal opinion is that your brain likes the look of a smaller bike under you, makes you feel big and strong. When i was racing in Europe many years ago, it was common for riders to talk about good days and bad days in terms like 'I had long legs today' or 'felt like I could crush my bicycle beneath me' while bad days were days where 'I couldn't get on top of my bike today', 'too much bike under me', 'short legs today' etc.. Combine that with the improved straight line stability you feel with a longer stem (it takes larger inputs to achieve similar steering angles) and your brain is happy.

I've participated in numerous blind product studies over the years where we controlled bikes or the wheels (I've done this twice with a bike manufacturer during development work around a pro team, and many times with wheels) with fabric shield tensioned between seat post and stem, flat black rattle can paint on everything, etc. In each of these studies, the entire subject group including pro riders, engineers, and other industry people with LOTS of experience, struggled to find any real differences between any of the bikes, until after the study was de-blinded and everybody (including me) instantly began to try and rationalize it all… This is just human nature, we all do it, and from experience, it is nearly impossible NOT to do it.

One of the major discoveries was that after controlling for seat post (round post shimmed into aero frame so as to not give it away) not a single rider found the aero road bike to be less comfortable, less compliant, etc, than the identically setup 'endurance' or 'roubaix' bike (clearly this leaves room for the aero seat post to be why people feel aero bikes are less compliant..seatposts generally have more effect on bike compliance in the lab than frames do, but that's another story). We ran blind wheel tests a couple of times a year at Zipp to benchmark competitive wheels and our own prototypes, and we also found that blinded riders were generally unable to tell the difference between stiffness and inertia, had no reliable feedback on weight, lateral stiffness, or comfort in general, and in the end were generally only able to pick out the aero wheels because they were riding laps around a closed park environment using power, so the more observant ones would notice speed differences. In the end, we sort of determined that when riders didn't know what they 'should' feel, they really struggled to find differences in stiffness, compliance and weight between frames or wheels. The strongest correlation we ever saw was to tire pressure, but not in the way you would expect. Almost everybody assumed the setups with lower tire pressure to be the endurance bike and would then score it exactly as you would expect a magazine review of a comfort bike to look…so we determined that we all naturally would latch onto something we were confident in, in this case comfort, and then would proceed to perceive everything you expected from that bike: less aero, less stiff, better damping, etc. Imagine the shock for the group when it turned out that the it might have been a super stiff race bike, or an aero road bike! Let the rationalizing begin!"

My main objection is that measuring the aero performance of a bike (which is something extremely complicated and questionable by itself) cannot tell you how fast a frame is on an actual race. Certainly the claims of several minutes gained in a 100km course are false IMO.

Can you list any other factors that affect rider speed besides CdA and Crr? Have you got objective data to support this?

[kgt]

I think I have already make myself as clear as I could. There was a Canyon engineer OTOH that was clear that pro riders are faster on the equipment they fell better.

[53x12]

kgt, as a supposed engineer you would know that CdA, bike weight and crr are the 3 major factors that determine how fast a rider can go for their particular power output. Do you agree with that?

You keep saying you don't believe that "aero components have no use" but want to put them in this little box of only being useful for a flat TT, track...etc. What is the difference between a flat TT and a flat road race? Sure in a road race you are protected by the peloton somewhat, but regardless there is still wind resistance that needs to be overcome even in the peloton. Your aero gains are less in a peloton, but still exist. Also, many riders are off on the front pacing the peloton, try to go for a solo breakaway or try and win it at the sprint. Those are specific cases in a road race than an aero frame will work to save watts.

You keep saying how your opinion is so obvious, but I have yet to see data to support this supposed obvious opinion you hold. If it was so obvious, seems there would be some data in support of it. Rather, the data I have seen from manufactures, 3rd party entities and even user field testing is that you are wrong. In each and every point. So in an age of evidence based decisions, show me the data. I don't rely on what people's feelings or biases are. I rely on the data.

So show some data to prove us all wrong and how you are right. I bet even your bosses, customers or government agencies require data to back up your assertions for an engineering design. They don't just give you approval because "kgt" said so. They want you to show it in a proposal detailing the details and reasons and data behind a particular decision.

Btw, I know you know that your 6.7 kg Cippo bike would be faster climbing than your 6.7 kg Cippo loaded with weights to 13.4 kg. So not sure why you don't understand the same principles for CdA.

[kgt]

kgt, as a supposed engineer you would know that CdA, bike weight and crr are the 3 major factors that determine how fast a rider can go for their particular power output. Do you agree with that?

No, I don't.

[Ahillock]

I don't have to prove something that becomes obvious in every single road race, from amateur to pro level (Sagan just lost a sprint on his venge btw).

Btw, Gaviria just won a close sprint the other day on a Venge ViAS. So what is your point?

No one is claiming a aero road bike rides on its own and has its own power source (unless mechanical doping). A bike will always rely on the power of the rider. What you fail to understand with the asinine arguments you use over and over is that a bike race consists of race tactics (some riders are good at this, other riders aren't), rider strength (who is the strongest rider and most in shape), rider determination (some riders seem to have more determination to do whatever it takes to win), how fatigued the rider is from the days race, team tactics (how well the team can get the rider into a position to go for the win).

The issue of aero road bikes is not rider A on an aero road frame vs. rider B on a non-aero road frame as both riders could vastly different in their abilities and strengths (like trying to compare Cav on a Tarmac vs. Andy Schleck on a Venge ViAS).

What you need to do is compare rider A on an aero road frame vs. rider A on a non-aero road frame.

[Krackor]

Since we're talking about pro races and whether an aero frame matters:

The day after Sagan lost his sprint to GvA at Omloop Het Nieusblad, Jasper Stuyven won Kuurne Brussels Kuurne in a 17 km solo breakaway after spending much of the day in a breakaway group. He was riding a new Madone, with Aeolus 6 wheels, Ballista helmet, tight fitting clothing, and rode most of his solo effort in the invisible aerobars position. He won by 17 seconds over Kristoff who was sprinting from the peloton.

Tour's test results say that the Madone saves 18W over the Storck, which is going to be an underestimate at the speeds Jasper was moving. Realistically it's probably 50-100% more than that since he would have been doing 50-100% more than 204W - a pro like Jasper is probably doing about 400W in a 20 minute effort at the end of KBK. But we'll go with 18W as a conservative estimate.

On page 19, 53x12 posted conversion factor of 5W = 0.5 s/km saved. 18W saved over 17 km would be 18 / 5 * 0.5 * 17 = 30.6s. (This is more like 60s if we use realistic power numbers.) For Jasper, if he were riding a mediocre "aero" frame like the Storck instead of the Madone, it would have taken him from 1st place and the biggest win of his career yet, to finishing somewhere around 30th place. That's not to mention all the energy saved in the race leading up to his solo attack.

Were you watching Paris-Nice this past week? Contador finished just 4 seconds back on GC to Thomas. Contador clawed back 11 seconds on the final stage. He attacked on Col d'Eze and had nearly a minute advantage over Thomas when they crested the top, but that advantage came down to only 5 seconds at the line in the high-speed descent in the last 15 km of the race. Contador was riding a Tarmac. What could he have done on a Venge Vias? Maybe he couldn't have gotten as much of an advantage on the climb. (Anyone care to make a calculation there?) Surely he could have maintained the additional 4s advantage he needed to win the race if his bike had been more aerodynamic. It matters so much on descents where speeds reach 70 kph. 4 seconds over 15 km is in the ballpark of 2.5W by the conversion factor above. A faster frame could have easily made up that difference. He also was riding low-profile wheels and a round tube handlebar. Changing either of those could have also made the difference.

It's absolutley daft to claim that an aero frame doesn't matter except for flat TTs or on the track when one can easily find multiple examples in the past two weeks of a major road race being decided by significantly less than the difference an aero frame makes. How about some numbers to back up the claims made by the aero skeptics? I haven't seen any yet, which is telling. It's always subjective this and feeling sluggish that. The racers who hold on to these neuroses will fall behind. The racers who are open to innovation will benefit. This is a sport where Hoogerland rides on after getting ripped to shreds by barbed wire, and Contador continues to climb a mountain after fracturing his leg. The psychological strength is there. A rider has no one to blame but themselves if they can't take advantage of an aero bike.

[53x12]

kgt, as a supposed engineer you would know that CdA, bike weight and crr are the 3 major factors that determine how fast a rider can go for their particular power output. Do you agree with that?

No, I don't.

You don't think CdA (rider + bike), bike weight (should make this system weight with rider weight included) and crr are 3 major factors outside of the riders physical shape and power output? Why not?


Sounds like you need to read this scientific article published in a peer-reviewed journal:

The science of cycling. Factors affecting performance
Faria EW, Parker DL, Faria IE.
Sports Med. 2005;35(4):313-37.
https://www.researchgate.net/publicatio ... e_-_Part_2

[53x12]

For others reading this thread that wan't to know the forces and factors from a physics standpoint influencing a rider's speed, here they are:



http://www.analyticcycling.com/ForcesPower_Page.html



Don't believe the snake oil salesmen that will sell you on elastic formation, center of mass, balance...etc.

[kgt]

@Krackor
This kind of deductivism is very simplistic IMHO.

@ 53x12
Actually the paper confirms my pov.
"Factors such as body mass, height, saddle position of the cyclist, type and aerodynamic characteristics of the bicycle and cyclist’s apparel, rolling resistance of the surface, wind, temperature, air density, humidity and many more have proven valuable in the prediction of performance."
In other words: aerodynamics is just one of the many parameters that influence the performance.

[kgt]

"The transfer of power from the human body to the drive train of the bicycle depends upon the crank length, longitudinal foot position on the pedal, pedal cadence, seat height and seat-tube angle (STA). Moreover, the cyclist’s performance is influenced by the bicycle profile and cyclist’s attire."

[53x12]

Actually the paper confirms my pov.
"Factors such as body mass, height, saddle position of the cyclist, type and aerodynamic characteristics of the bicycle and cyclist’s apparel, rolling resistance of the surface, wind, temperature, air density, humidity and many more have proven valuable in the prediction of performance."
In other words: aerodynamics is just one of the many parameters that influence the performance.

Nice to see you are starting to come around in short order when you said you didn't agree with the 3 things that I listed as 3 major factors influencing a rider's speed:

kgt, as a supposed engineer you would know that CdA, bike weight and crr are the 3 major factors that determine how fast a rider can go for their particular power output. Do you agree with that?

No, I don't.

Don't forget this from the paper:

"Among those factors, aerodynamic resistance is the major resistance force the racing cyclist must overcome. This challenge can be dealt with through equipment technological modifications and body position configuration adjustments."

or this one: "Moreover, aside from equipment, the cyclists riding position has an important consequence for both speed and metabolic cost."

[53x12]

"The transfer of power from the human body to the drive train of the bicycle depends upon the crank length longitudinal foot position on the pedal, pedal cadence, seat height and seat-tube angle (STA). Moreover, the cyclist’s performance is influenced by the bicycle profile and cyclist’s attire."

You realize that aero road bikes have the same or very similar geometries as regular non-aero road bikes. Right?

- The crank length of a rider on an aero road bike would be the same as the crank length of the same rider on a non-aero road bike.
- The foot position of a rider on an aero road bike would be the same as the foot position of the same rider on a non-aero road bike.
- The seat height of a rider on an aero road bike would be the same as the seat height of the same rider on a non-aero road bike.
- The pedal cadence on a aero road bike can be the same as the pedal cadence on a non-aero road bike.


"Bicycle profile" sure sounds like it would benefit from something like this:





overs something like this:

[Krackor]

kgt, you seem to be the only person addressing the claim that "aero is everything". Of course there are factors other than aerodynamics that come into play. Who has claimed otherwise? This is another motte-and-bailey retreat from you. First you claim that aero doesn't matter much for racing. Then someone brings solid data indicating that it does matter for racing. Then you claim that aero isn't the only thing that matters for performance, or that the wind tunnel isn't a perfect simulacrum of a real race. Of course no one disputes that, and after a little while you're back at step 1 claiming that aero doesn't matter much for racing. You really have proven you have nothing useful to add to the discussion.

I agree - retrospectively calculating the effect of an aerodynamic frame is a simplistic and speculative way to judge what would have or could have happened. (What does that say about your repeated references to pro cyclists' choices and performances?) Isn't it also simplistic to claim that aero only matters in isolated time trial examples?

Racing is a game full of unpredictable factors that influence the outcome. A racer can train hard all year chasing a 2% FTP increase, but their target race may be ruined by an ill-timed puncture or cross-wind echelon. A racer has to control the factors they can control to give them the best chance they have at overcoming the factors they can't control. The larger the improvement in factors you can control, the better chance you have of winning. There's no certainty about it, just like there is no certainty in any other factor that goes into cycling performance. Your radical skepticism is not useful though. We do the best we can with the information we have, and the information we have says that aerodynamics, including an aero frame, is a very important part of cycling performance, and it would be foolish to ignore it over such a nebulous thing as the emotions and feelings conferred by a frame.

[kgt]

I do not disagree. As I was always saying: aerodynamics of the frame is just one of the many parameters that affect the overall performance. It just seems that for some of you an aero frame alone gives you a considerable advantage while I think its advantage is almost negligible.

[Krackor]

What kind of advantage do you consider non-negligible? Where is the threshold for you?