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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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I pay attention to the big announcements and white papers.

I value independent testing and analysis more. The bottom line for me is that if I am dropping the amount of money it takes to get a high end tri bike, I am going to use (and critically evaluate) every bit of information I can get my hands on.

If I can't get some credible data about the bike, or the major components like wheels I will not consider making a purchase. I also won't consider buying if that data indicates the bike is significantly slower in the wind tunnel.
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [ In reply to ]
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No.

For me, the purchase of a bike is based on expected durability, quality, and price of the bike. For me, triathlon is a hobby and it's important to maintain perspective of this. It's a hobby that is very expensive, and only supports a selfish 'need' and my triathlon results are not gonna pay for my son's college education.

I'm kind of like how aerospace selects materials, going by proven reliability over minor technical performance benefits (typically). I bought a P2 after the model was already on the market for several years and had proven its value. I still ride it today, 6 years later, so that means it has shown to be a reliable purchase. And if all goes well, it will easily last me another 6 years. My road bike is a Merckx that celebrated its 10th year this year. I'm hoping it will last another 10.

It's the same for components, I am not looking for the most complicated latest designed brake X or cable Y or electronic this or mechanical that. I'm using shimano components ranging from 105 to Dura-Ace depending on what came with the bike when I bought it. I don't replace Dura-Ace with Dura-Ace. I replace Dura-Ace with ultegra or 105.

I consider myself a strong biker and that to me confirms there's no need for a faster top of the line bike. I am usually in the top 2-3 fastest bikers in local races. My IM MD bike split last year was 4:45. Not trying to brag but the point is that a bike such as my 2009 P2 still has plenty of potential and i don't see how a faster bike would make a dramatic difference. If I want a dramatic difference I should start by eating less junk and swimming more. :-)

So to answer the question about marketing... I want proven reliability. Mechanical performance. Why this bike will be fast AND will last a lifetime. Why it is stiff and not too stiff. Why it's comfortable. Why I will love this bike for the next 10 years without feeling like I'm using something that belongs in a museum.


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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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Hmmm... Looks like a lot of no votes yet just try to launch a new, state of the art performance wheel like Dished Wheels, without the data and you'll get skewered.

Does data only count for wheels but not for frames?

I tend to view it the opposite way. Assuming a proper fit is "possible" on various bikes, then the data does matter regardless of my fit because I can have an equally bad, or good fit, so the variable left is the bike.

Of course, in the real world of budgets, it also comes down to the speed / cost ratio.
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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The only tunnel data I feel like I can trust is from Zipp and Cervelo since so many tests have been done against these two brands and the data is pretty much the same from test to test. I like reading the Tech Papers but I want to see data and have it backed up by independent sources.

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Last edited by: BryanD: Oct 15, 15 20:52
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [BryanD] [ In reply to ]
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The thing that boggles me about always trying to sell bikes in the same way is the "blank space".

The blank space is everything left over to sell a bike. Everything left besides bicycle aerodynamics.

Things like:

  • Appearance (more important than most of us are willing to admit).
  • Weight.
  • Warranty.
  • Frame stiffness (Note here: one highly credible brand has a unique feature that makes their bikes stiffer, but none of their P.O.P. displays mention it.)
  • Component specification. (I dare someone to run an ad that says, "Best value in a Dura-Ace equipped triathlon bike).
  • Fit. (Everyone acknowledges the importance of bike fit. No manufacturer actively uses it as a selling tool in their marketing.)
  • History.
  • Construction technique.
  • Durability.
  • Ride quality.
  • Comfort.
  • Ease of maintenance (honorable mention to Quintana Roo for their "Ease of Packing" campaign for their very good PR bikes).
  • Mise en scene (the cache' of the brand, an analogue that is more important than most consumers are willing to admit since some of it is subconscious.)

It took less than 2 minutes to list 13 new conversations bike companies could be having with their customers instead of the same one they are all having.


It's like being in a room full of people shouting. And someone needs to whisper to truly be heard.

Tom Demerly
The Tri Shop.com
Last edited by: Tom Demerly: Oct 15, 15 21:51
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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this is purely from a technical stand point, (and assuming manf. dont fudge data, I think they dont!)
YES and NO..

YES - Because, Wind tunnel data can be credible if bikes are tested with same protocol. For ex: if test data come out of A2 wind tunnel from different manufacturers, we can rely on data, as A2 typically has a standard test protocol, use same tare/model mount setup etc. Also there are a lot of independent bike aero test comparisons by publishers out there which can be credible.

NO - because, if they are coming out of different wind tunnels, then there is no apple to apple comparison (wind tunnel size/blockage differences etc.).

Adi Prabakar
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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To be fair, Cannonade are trying to go down that route with the Slice.
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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Idk but I think there are other cheaper ways to get faster for way less money
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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Not a lot.

For me, I pay more attention to what comes out of the testing done by Jim at Ero and Brian Stover in the tunnel. Try and pay attention to trends and the things that generally test well.
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Goobdog] [ In reply to ]
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Goobdog wrote:
Hmmm... Looks like a lot of no votes yet just try to launch a new, state of the art performance wheel like Dished Wheels, without the data and you'll get skewered.

Does data only count for wheels but not for frames?

I tend to view it the opposite way. Assuming a proper fit is "possible" on various bikes, then the data does matter regardless of my fit because I can have an equally bad, or good fit, so the variable left is the bike.

Of course, in the real world of budgets, it also comes down to the speed / cost ratio.

The criticism of OISHEO had nothing to do with lack of data (well, very little anyway), and everything to do with the claims he was making and the fact that he was flat out lying, along with stealing Flo's website.

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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [SteveMc] [ In reply to ]
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SteveMc makes a good point, and there should be two brands with honorable mentions here:

1. Cannondale has maintained a good conversation about bike weight and ride quality on their tri bike.

2. Quintana Roo has discussed the mechanical simplicity of their PR bikes for bike packing and maintenance.

Interestingly, one other non-aerodynamic major (very major) triathlon/aero bike brand has a key feature unique to them that I will suggest does provide a tangible benefit across the entire performance envelope. But they never talk about it.


I've always thought that's odd, but then again, that's just me.

Tom Demerly
The Tri Shop.com
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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But you've also never thought that wind tunnel data was applicable in the real world. Or at least that was the case in the past and a source of a lot of arguments/discussions in the forums. I'm guessing you are no longer working for FELT, so you are free to continue back down that road again?

Aerodynamics are really only one part of the puzzle, and they are real and measurable. I've spent a lot of time in the tunnel with Brian and at the track with Jim doing our AeroCamps as well as doing independent testing. I can tell you for a fact that the gains we have seen are realized on the race course.

I'm also a big proponent of a proper fit. Stiffness is a red herring. Lightness is also secondary to aero.

The process is get a proper fit then find the most aerodynamic frame that works for your fit and your riding style. A frame from FELT, Scott, Cervelo, or Trek will all fit the bill nearly equally but fit differently. Cervelo is a low yaw bike and the others perform better outside of 7.5 degrees. If you are slower or racing at Kona the other bikes will perform better aerodynamically.

Beyond that, it is color and what you LBS happens to carry.



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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [GreenPlease] [ In reply to ]
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GreenPlease wrote:
I tend to listen to the proclamations of companies such as Trek, Cervelo, and Specialized (in that order) because I feel they have earned it. Everyone else I tend to take with a huge grain of salt. I'll look at their whitepaper and their data but I'm constantly looking for holes in it. When it comes to pro endorsements, I tend to mostly disregard them except for someone like Gomez swimming in a Roka wetsuit. If he's wearing that suit I know, at the very least, it's not slowing him down.

Alternative marketing script? Sheesh, that's tough. All I can say is that if you're going to put out data make sure it's good data with a solid methodology behind it.

I agree with your comment. I would add that the Giant marketing is interesting. The drag graph they published pretty much showed that most people would be better off with a Speedconcept or a P5 because they are clearly faster in the 0-5 degree range.

The alternative marketing angle I would appreciate would be "Don't buy are bike if you you match this set of parameters", but that isn't going to happen.
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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I've always taken the trust but verify. You look at enough of them and know a P5 has to be the fastest at 0 yaw. I suppose someone else is gonig to beat it, someday? but the best ones show the P5 doing what it does best, and ideally you see the p5, the speed concept, and some others that have been baseline bikes frequently, and in the right relationship, with the manufacturer's bike slotted in where it belongs.

While it won't be the only thing that I buy a bike off of, a lack of such data would stop me cold from buying a bike.
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [JasoninHalifax] [ In reply to ]
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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Tom Demerly wrote:

2. Quintana Roo has discussed the mechanical simplicity of their PR bikes for bike packing and maintenance.

In line with what I said before, this would be a big factor in getting a bike because simple bike packing and maintenance means better reliability and in the end, better performance. It also helps mentally when you know you can fix a problem and won't be stuck on the road or not able to use your bike while you're waiting for replacement parts.

For me, QR would definitely be an serious option if it weren't that their PRSix is so expensive (which no longer makes it an option).


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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [jackmott] [ In reply to ]
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jackmott wrote:
well I guess you are lucky you find airfoils visually appealing

Doesn't everyone?
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [chaparral] [ In reply to ]
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chaparral wrote:
jackmott wrote:
well I guess you are lucky you find airfoils visually appealing

Doesn't everyone?

strangely, no



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
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Freelance sports & outdoors writer Kathryn Hunter
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [jackmott] [ In reply to ]
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My tastes run towards "simpler and cleaner is better".

When someone comes out with something in general terms, it looks like it makes sense, I'll say "that looks like its reasonable". So if tririg says that their brake is faster than a sidepull Dura Ace, I believe that. Where I roll my eyes is when specific numbers start getting attached, when someone claims a detectable difference without showing the variability in the measurements. That's where I stop caring.

It is when someone claims one thing, and you have no idea if their claim is real or noise, then that's an issue. I haven't bothered to look at white papers in a long time, because when I did, there was no way to reasonably discern signal from noise. So I've given up.

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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [JasoninHalifax] [ In reply to ]
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Well you can always look at the totality of white papers and notice trends.
Like Cervelo still wins in other people's white papers, heh

The nice thing is now almost all of the major brands have good stuff. You can't go very wrong. So shopping by looks ins't likely to screw you anymore anyway.


JasoninHalifax wrote:
It is when someone claims one thing, and you have no idea if their claim is real or noise, then that's an issue. I haven't bothered to look at white papers in a long time, because when I did, there was no way to reasonably discern signal from noise. So I've given up.



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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There are some very important things in the white papers beyond the wind tunnel models. The first is the testing protocol. If one company tests with bottles and the other does not, it is good to see the difference and gives the consumer valuable data. They also will detail things like the size and aero-bar configuration, this can explain difference in results between different tests. This sort of information can explain why one bike ends up on top in one test and another is on top of another test.

The second aspect is it shows the design process. Take the speedconcept for example, both the whitepaper are pretty great. The first one showed their process for developing their tube shapes. They started in CFD just looking at individual tube shapes, then took a bunch of those tube shapes to the windtunnel. Then they went back and then compared the wind tunnel to the CFD and were able to correlate their CFD process to the windtunnel. Only then did they start designing the bike as a whole in CFD, then went back to the windtunnel to test some of the CFD models. Then went back again to correlate their CFD. This sort of methodical process of building up knowledge from a base and confirming bit by bit, is not guaranteed to result in a fast bike, but there is a very good chance a fast bike will be the result. This sell to me the results in the windtunnel, because clearly they did the right things leading up to final product. Similar thing for the 2nd speed concept white paper. This one had lots of information about what yaw riders actually see. There is lots of good detail information in there how they get good yaw data, like making sure their measurements were not affected by the frame behind the measurement devices. They actually put their bike and rig in a wind tunnel to make sure it worked correctly. Then they used that actual yaw data to determine what yaw to optimize the frame for.
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [jackmott] [ In reply to ]
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True, but that's not really what Demerly was asking in his OP.

I can look at the totality and say "OK, a P2 or P3 is going to be pretty good"

Or I can look at something like a PlanetX Exocet 2, which has no white paper that I'm aware of, but say "that looks pretty similar to the P2", and I can route the rear brake cable more cleanly, so it probably isn't terrible.

i.e. I can make claims in pretty general terms, but not precise claims.

What I am not comfortable doing is saying that the P2 is going to be 2 watts less drag at 25 mph than the ShivTT, or whatever highly accurate claim is being made.

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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [Tom Demerly] [ In reply to ]
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No.

It's actually not complicated, if you look at it without getting bogged down in the hype/details.


Here is the question that every triathlete should be asking regarding how fast their bike will be:

"Will it make me measurably faster on the race course?"

Wind tunnels do a good job in teasing out theoretical tiny gains with small aerodynamic changes, but all the science and hype is moot if there is no reliably measurable effect in the real world, on a real outdoor race course.

To date, there is NO bike manufacturer that will lay claim to even saying you will be measurably +20 seconds faster outdoors with their superior aerodynamic bike. And believe me, if any manufacturer had good data showing this type of effect reliably outdoors, you'd be seeing it in their ads, since they'd be the only ones good enough to pull it off.

To all those folks who say, 'well the wind tunnel gives the cleanest results which should directly translate to faster outdoor times", it's all totally meaningless if the 'noise' from outdoor practice dwarfs the speed gains.

It sounds like 'duh' common sense, but to say it again explicity - if you cannot reliably measure a speed benefit outdoors in the same race conditions that serves as what this hardware is meant to be used for, it's not making you any faster even if the wind tunnel results says you should theoretically be faster.

Now if the wind tunnel results were an excellent proxy for outdoor results (meaning there's good evidence showing that the small advantages in a wind tunnel translate to well to measurable outdoor results), I'd be more inclined to believe the data, but to date, there is not once single bike manufacturer, even ones with millions of dollars of R&D, that make the claim of having an outdoor, measurable real-world difference.

Note that this doesn't mean I don't believe in aero gear. There is no doubt that aerobars vs non-aerobars (in a good position for both) will give you a real, outdoor measurable speed advantage. There's also no doubt that non-UCI positions like the full recumbent position are much faster than standard positions in flat courses. But I would make the claim that bike manufacturs resort to wind tunnel data because they are unable to provide convincing outdoor real data that their bikes are any faster than their competitor road/tribikes.

I'd be more than happy for people to prove me wrong - show me the data showing that Cervelos, or whatever bikes are faster outdoors using a convincing sample size, and I'll gladly give the thumbs up to believing their claims that their bikes truly are faster.
Last edited by: lightheir: Oct 16, 15 8:24
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [JasoninHalifax] [ In reply to ]
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JasoninHalifax wrote:
True, but that's not really what Demerly was asking in his OP.

I don't really talk to Demerly.



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
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Re: How Much Credibility do you Assign to Bike Brand Wind Tunnel Claims? [lightheir] [ In reply to ]
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lightheir wrote:
To date, there is NO bike manufacturer that will lay claim to even saying you will be measurably +20 seconds faster outdoors with their superior aerodynamic bike. And believe me, if any manufacturer had good data showing this type of effect reliably outdoors, you'd be seeing it in their ads, since they'd be the only ones good enough to pull it off.

Cervelo, Specialized, Trek, at a minimum,I'm sure there are others, do aero testing outdoors with various "Chung on a stick" type devices.

additionally, figure 2 in the following study shows that wind tunnel measured CdA has strong predictive power for outdoor real world results:

http://www.wisil.recumbents.com/...20road%20cycling.pdf

This does not represent the only validation of wind tunnels vs real world, it was just handy.

I think the degree to which you mistrust wind tunnel testing is misplaced.



Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter
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