Road Bike Aerodynamics

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climbandpunishment
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by climbandpunishment

The legal aspects were something I'd considered but the lack of specific mentions was more out of respect for manufacturers and the engineers behind the designs. Though inevitably certain bikes are going to look worse as a consequence of distributing this, I wanted to avoid dragging anybody's name through the mud.

I can't update the document instantly whenever a manufacturer has a new, much more believably aero frame, nor can I name every single frame that doesn't appear to live up to expectations, so I didn't think it fair to name and shame. Plus, it's always a possibility that I'm wrong in specific cases, since I'm only human and can't rigorously test every frame.

And thanks DanW; it was originally aimed to be written from that perspective, but devolved somewhere in the process. I'll work on bringing it back around to that sort of wording and message.

DanW
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by DanW

I don't think a naming and shaming crusade helps anyone. You may be frustrated with some frames on the market but this doesn't help anyone to vent it publicly. Nor does it really help anyone to give a thinly veiled critique of every new frame coming to market. Keep it general and note your observations from your testing. Everyone is a winner then.

I'd also start with the key points you want to make, then pad it out. Currently the important information is a bit hidden and some points that might be interesting to a would-be customer aren't covered.

That said, I applaud you for putting this together and always love to learn more about our fantastic hobby :thumbup:

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wingguy
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by wingguy

I don't think a naming and shaming crusade helps anyone. You may be frustrated with some frames on the market but this doesn't help anyone to vent it publicly.


That makes no sense at all. If the object is to help prospective buyers recognise which frames are more or less aero then the single most helpful thing possible would be to say which frames are more or less aero. QED.

wingguy
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by wingguy

climbandpunishment wrote:The legal aspects were something I'd considered but the lack of specific mentions was more out of respect for manufacturers and the engineers behind the designs.


But if you think they've made a bad bike, either through lack of true R&D or too much emphasis on styling over engineering then why does that deserve respect?

What's the harm in giving an example of a bad aero bike?

DanW
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by DanW

if I want an aerodynamic bike, how can I, as a consumer, choose one without a supercomputer or wind tunnel?

As an aerodynamicist by trade, I thought I'd try to put together a set of guidelines that would make it easier to eyeball-judge a given bike and its design methods, and to evaluate how much truth there is to a given company's claims. I obviously can't write a set of rules that will always be unimpeachable for every frame, but I figured if I can help people identify the best few frames that likely really do live up to marketing claims, it'll benefit the industry through competition and therefore me when I look to buy a new bike.


Wingguy, I interpret this as a set of guideline to know what to look for in an aero frame. The guidelines are currently a little hidden and could be clearer. It doesn't need to be model or brand specific or even apply in all circumstances (as the OP already says) as it is still good info to arm a buyer with, to start getting people in to making informed decisions. There are some interesting discussions in the OP's frame build thread so I think it is nice to effectively have a summary of all of this which is what seems to be happening.

The author can only speak to their own testing and experience or reviews of available literature. It doesn't make any sense to completely discredit another company or model based solely on these general guidelines as aerodynamics is a complex subject with a lot of variables.

Short of testing all existing designs, if you want to start digging in to specific manufacturer claims then you have to look at all the available data, test methodologies and conclusions drawn to see how they all stack up together, find strengths, limitations, etc... as you would with any body of scientific work. I wouldn't expect to be able to say x frame/ bike is absolutely the most aero. You'll end up with a long list of "bike a is most aero in condition b, bike c in condition d, bike e for rider position f, bike g with wheels h" and so on. That doesn't seem to be the purpose of the document and would be a heck of a literature review :beerchug:

wingguy
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by wingguy

The author can only speak to their own testing and experience or reviews of available literature. It doesn't make any sense to completely discredit another company or model based solely on these general guidelines as aerodynamics is a complex subject with a lot of variables.


If the guidelines really are useful then it makes perfect sense. If the author says he can eyeball which aero bikes aren't aero how in the world could it not make sense to give an example of an aero bike that isn't aero and how he can tell it isn't? That's crazy talk.

The only way it wouldn't make sense to use those guidelines to call out an aero bike that isn't aero is if the guidelines aren't reliable enough to make that judgement, in which case what's the point of any of it?

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Calnago
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by Calnago

I think most people can get where the author is coming from. Good for him if he wants to try and give some easy "at first glance" intuitive guidelines based on the actual in depth knowledge that he has. And it sounds to me like his knowledge is quite substantial. I believe he has more than the basic level of knowledge on the subject that enables him to reasonably evaluate a lot of factors without the use of a wind tunnel, at least on a comparative basis.
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RyanH
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by RyanH

I'm sure pointing out specific manufacturers by name is a good way to get blacklisted in the industry. So, if the OP wants to possibly work in the industry, it might not be the best career move.

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H0RSE
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by H0RSE

If you're going to touch this subject then do it properly. The subject of a fluid dynamics is relatively rigourous and covers everything from boundary flows, turbulence modelling, CFD and PDEs to say the very least. The subject has proper applications to far heavier stuff such as aeronautics and flight dynamics. F1 and applications to bicycles all come far later as mere corollaries t of the major princicples involved. Almost everything to do with aerodynamics with respect to bicycles can literally be explained in one sitting.

In terms of bicycles the flow models are essentially around laminates really. What we've seen since the turn of the century is corporations are willing to invest and have, in researching frame design to optimize what are certain performance characteristics in frame design. By contrast, before it was like, take seven tubes and slap welds amongst them. Whilst there has now been a concerted trend to genuinely push things forwards there have also been some dumb innovations along the way as well. The three characteristic performance features have been frame weight, stiffness, comfort, and now much more lately aerodynamics.

wingguy
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by wingguy

@Calnago That's fine. But if he has this knowledge and wants to give people a method to easily evaluate aero frames, then how could it possibly be bad form for him to... wait for it... evaluate an aero frame using that method?

That's like saying you'll happily give someone a set of scales to weigh a frame, but you think it would be disrespectful to the manufacturers tell them which frames you've weighed yourself. It doesn't make any sense.

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H0RSE
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by H0RSE

In that respect Jam Sandwich, marketing speaks for itself. You need a proper education in the subject as it is to call out what's a dumb idea or looks like it in the first place. I know one or two major companies who have done this in the name of style over substance.

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