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Re: Hambini's take on Zipp Dimples ROFL [weiwentg] [ In reply to ]
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Okay, so here are my .02 cents worth (and yes, probably only worth .02 cents for sure)..... I don't care about Hambini or anyone else's data, IF AND ONLY IF you are using bearings (be them BB, wheels, or even headset) that have been in service for 10,000Km. If you are serious about racing and squeezing every little bit of "free-speed", then why the hell are you using anything that has been in service for 10,000Km???

Team Zoot-Texas, and Pickle Juice
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Re: Hambini's take on Zipp Dimples ROFL [RowToTri] [ In reply to ]
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RowToTri wrote:
mauricemaher wrote:

I find it weird that someone would just hand over a brand new frame to hambini “to have a go” at fixing it, as opposed to just getting a new frame from the manufacturer.

Maurice

Talk about placing your life into questionable hands...

On a weird note, he has now removed any and all materials relating to the “aero test” (video, test on his blog) now mysteriously gone from the internet.

Maurice
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Re: Hambini's take on Zipp Dimples ROFL [mauricemaher] [ In reply to ]
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Re: Hambini's take on Zipp Dimples ROFL [xyei] [ In reply to ]
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xyei wrote:
I just registered into this account to say a few things.

First off, I got into this forum and post as I'm subscribed to Hambini's channel. Now don't let that get you all riled up.


I'm currently a ME student and I discovered his channel after looking into aftermarket solutions to 'inadequately-thought' design conclusions by some manufacturers. I could give less crap about aerodynamics in my current level right now and I only watch his channel for those one-off solutions to piñata-quality frames sent to him. On that regard (the aero jazz), you can go ream him as much as you want.

On one thought though: disregarding his behavior and practices, I think his premise is actually legitimate when it comes to planting skepticism towards 'innovation' by certain bicycle manufacturers, as you have all been projecting towards his line of work, tests, and data. Having perspective from a not-so-scientifically-rigid side of cycling, I see that casual people seem to be just deepthroating whatever the industry has been biffling out.

Technical forums (whether ST is one of them or not depends on you) may have been skeptic already, but the casual community has not been; at least not sufficiently enough. So while you can all go and rape the aerospace street-shitter, I think he still has his place in the aformentioned subject.

After all, isn't 'engineering' technically "providing solutions that are significantly positive-sum"? To that standard, many designs in the cycling industry aren't really 'engineered' enough. And seeing that they're really thriving, I guess there isn't enough doubt in the minds of the consumers.

For me personally, Hambone's opinion on which is crap or not tends to be a baseline if something is worth buying or not. You may see that as a very vague standard, but seeing as he doesn't prefer threaded BBs as much as I do, he must be a tad more nitpicky than the standard bloke. I'm not a die-hard racer, so for as long as my bike is 'aero' enough and structurally decent, I could give less manure about some dimples on chinese carbon.

Anyways, I haven't really explored this forum enough, but if it's not done much yet, I think you all should also give more attention to these manufacturers with regards to their umm... revolutionary, watt-saving butterfuckfest. Whatever the fuck happened to actual human training, seeing that a novice with the highest-end componentry couldn't even beat an ancient hour record.

I am a mechanical engineer (graduate degree) with significant real world experience in CFD among other skills. Not involved in bike design of any kind by the way and I am by no means an aerodynamics expert (not even close to a rookie) but have the technical background to understand the fundamentals. I often cringe when I read some of the studies, concepts, or designs by some bike manufacturers. Nobody is perfect, but I often feel an air of arrogance in the bike industry and very little ownership for some of horrible concepts and products. Having said that, there is also a lot of great innovation and good engineering. I find the "aero" side of the industry to be the one with the most snake oil.

About Hambini, it probably won't sit well with a bunch of people in these forums, but the guy is actually qualified and competent specially with aerodynamics. I disagree with some of the stuff he says (or how he conducts himself sometimes) but I enjoyed his chat on TT position discussing steady state/transient, praying mantis position, etc.
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Re: Hambini's take on Zipp Dimples ROFL [imswimmer328] [ In reply to ]
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I recall when the sub-9 was released as "first wheel that sucks the bike forward" or something like that. I would love to see those results. Too bad the wheel was discontinued.
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Re: Hambini's take on Zipp Dimples ROFL [Engner66] [ In reply to ]
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I am also a mechanical engineer, currently finishing up my masters degree. The thing is, the whole premise behind his study is flawed significantly. We have been successfully able to model time trial performance using steady state wind tunnel data for many years now. Software like bestbikesplit has several highly accurate case studies presented, also worldtour cycling teams have their own models I hear. Therefore either the transient effect he speaks of isn't seen outside of his testing, or is negligible.

Additionally, not only is hambini a little all over the place in how he attacks people, but I am unable to find any publications of his, including a PhD dissertation, in any database. I don't think he is who he says he is at all.
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Re: Hambini's take on Zipp Dimples ROFL [xyei] [ In reply to ]
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xyei wrote:
I just registered into this account to say a few things....
My that's an unpleasant post to read!
I'll assume you plan to use a rather different writing style for your thesis.

I do agree that many, even most, cyclists tend to take much of the industry's assertions almost at face value, and I agree there's a huge amount of nonsense being perpetuated. Of course that's the case in virtually all marketing. It's incredibly easy to start imagining an assertion has some validity just because you've heard it so often, from so many sources. I'm fortunate to be very qualified to assess most of these assertions, and I can't guarantee I've never been caught out so I think it's rather unfair of you to be so scathing in your assessment of the typical, less prepared cycling customer and the members of this forum. I'm not shy in pointing out when people are talking crap, and it happens a lot. However, I do think you're painting with an excessively broad brush in your post.

As for Hambini. I don't think he's part of the cure. Industry can't be trusted to be honest and transparent because it's biased. But then so is Hambini. His tone is extremely unprofessional and creates a problem in terms of trustworthiness. It makes it extremely difficult, indeed virtually impossible, for him to admit any error without severe embarrassment. That's never a good idea if you want to be taken at face value.

I think there is some merit among his assertions, but he's devalued them, and made himself part of the noise. I simply couldn't be bothered listening to the guy without a very compelling reason.
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Re: Hambini's take on Zipp Dimples ROFL [xyei] [ In reply to ]
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xyei wrote:
I just registered into this account to say a few things.

First off, I got into this forum and post as I'm subscribed to Hambini's channel. Now don't let that get you all riled up.


I'm currently a ME student and I discovered his channel after looking into aftermarket solutions to 'inadequately-thought' design conclusions by some manufacturers. I could give less crap about aerodynamics in my current level right now and I only watch his channel for those one-off solutions to piñata-quality frames sent to him. On that regard (the aero jazz), you can go ream him as much as you want.

On one thought though: disregarding his behavior and practices, I think his premise is actually legitimate when it comes to planting skepticism towards 'innovation' by certain bicycle manufacturers, as you have all been projecting towards his line of work, tests, and data. Having perspective from a not-so-scientifically-rigid side of cycling, I see that casual people seem to be just deepthroating whatever the industry has been biffling out.

Technical forums (whether ST is one of them or not depends on you) may have been skeptic already, but the casual community has not been; at least not sufficiently enough. So while you can all go and rape the aerospace street-shitter, I think he still has his place in the aformentioned subject.

After all, isn't 'engineering' technically "providing solutions that are significantly positive-sum"? To that standard, many designs in the cycling industry aren't really 'engineered' enough. And seeing that they're really thriving, I guess there isn't enough doubt in the minds of the consumers.

For me personally, Hambone's opinion on which is crap or not tends to be a baseline if something is worth buying or not. You may see that as a very vague standard, but seeing as he doesn't prefer threaded BBs as much as I do, he must be a tad more nitpicky than the standard bloke. I'm not a die-hard racer, so for as long as my bike is 'aero' enough and structurally decent, I could give less manure about some dimples on chinese carbon.

Anyways, I haven't really explored this forum enough, but if it's not done much yet, I think you all should also give more attention to these manufacturers with regards to their umm... revolutionary, watt-saving butterfuckfest. Whatever the fuck happened to actual human training, seeing that a novice with the highest-end componentry couldn't even beat an ancient hour record.

I am also a ME and I would suggest having a look at the NPSE code of ethics (or your locality’s equivalent). They do a good job of setting expectations around appropriate engineering behaviors, Hambinis not exactly in line.
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Re: Hambini's take on Zipp Dimples ROFL [Engner66] [ In reply to ]
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Engner66 wrote:
I am a mechanical engineer (graduate degree) with significant real world experience in CFD among other skills. Not involved in bike design of any kind by the way and I am by no means an aerodynamics expert (not even close to a rookie) but have the technical background to understand the fundamentals. I often cringe when I read some of the studies, concepts, or designs by some bike manufacturers. Nobody is perfect, but I often feel an air of arrogance in the bike industry and very little ownership for some of horrible concepts and products. Having said that, there is also a lot of great innovation and good engineering. I find the "aero" side of the industry to be the one with the most snake oil.

About Hambini, it probably won't sit well with a bunch of people in these forums, but the guy is actually qualified and competent specially with aerodynamics. I disagree with some of the stuff he says (or how he conducts himself sometimes) but I enjoyed his chat on TT position discussing steady state/transient, praying mantis position, etc.

Snake oil? Definitely. Lots of waffle and miniscule gains being sold as revolutionary developments. But what are these "horrible concepts and products" of which you speak? Have various brands in the industries made mistakes? Yes, they have - and they have corrected them. Is this more prevalent in the bike industry than any other area? Not that i know of.

As for Hambini's expert status on aerodynamics - all the stuff he says is pretty much the same that anyone experienced with bike fits also states.

His persona from a few years ago had a lot more credibility - but not as many clicks. Now he's like a child who realizes he gets attention when he acts up, and so he acts up more and more. There are so many exaggerations and overly-broad generalizations in his videos that it is actually painful to sift through the noise. Add to that his history of lying like a rug, and he is not a credible source anymore.

How many of you would pay attention to a scientist who, while knowledgable, lied about his data & exaggerated his results?

I suspect the reason Hambini appeals to so many people is because of that overly-simplistic vision he sells - "the bike industry is out to fool everyone, and i am the only one who tells it like it is". It reaffirms their beliefs that the Evil Marketing Guys are at it. Nevermind that this is just as idiotic as buying all the snake oil the industry sells.


--
Those who are slower than me suck.
Those who are faster than me dope
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Re: Hambini's take on Zipp Dimples ROFL [Engner66] [ In reply to ]
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Engner66 wrote:
I recall when the sub-9 was released as "first wheel that sucks the bike forward" or something like that. I would love to see those results. Too bad the wheel was discontinued.

I had one. Great wheel, but I once dropped it and it started to roll away from me. Due to the claimed aerodynamics, it just kept going and I was never able to catch it. Last I heard it has circumnavigated the globe twice now. The last sighting was crossing the steppe in Mongolia.
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Re: Hambini's take on Zipp Dimples ROFL [Engner66] [ In reply to ]
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Engner66 wrote:
I recall when the sub-9 was released as "first wheel that sucks the bike forward" or something like that. I would love to see those results. Too bad the wheel was discontinued.


Negative drag over some yaw angles is well documented in a number of disc wheels. Even some non-disc wheels.

I don't know if the Zipp was the first to publicly document that phenomena (I suspect not), or if Zipp exaggerated that effect in marketing to be a common condition rather than just at higher yaws. (though I've done some entire races at pretty high yaw, so it's not an effect to just ignore)

But the effect is likely real.







Last edited by: trail: Jul 10, 20 7:30
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Re: Hambini's take on Zipp Dimples ROFL [trail] [ In reply to ]
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Thanks for sharing. So it does seem as if the sub 9 was not the first since almost any disc would yield the same result?

I have a sub 9, in real world testing it has never performed better than my renn disc. Not a study or anything, just sharing my experience.
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Re: Hambini's take on Zipp Dimples ROFL [Engner66] [ In reply to ]
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I am no expert but here is someone else who I think might be believable saying there is negative drag or sailing effect:
https://www.swissside.com/...o-tip-sailing-effect
he purports in this short <2 min video to get 10 watts of added thrust.. free power. Marketing hype or aero reality? I have been in a sail boat and worked the sails as welI have felt the impact of a favourable wind on my S5. I hit speeds on a course I ride a lot which I can not replicate on my S3 with low profile wheels... but that is not doing any good science for sure just one point against many.
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Re: Hambini's take on Zipp Dimples ROFL [s5100e] [ In reply to ]
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Run the math on wind speeds and rider speeds for those huge yaw angles and you start to understand the charts are a bit much.

20 deg yaw? Cmon. Not to mention the forward speed used in a tunnel is 25 to 30mph. That takes a solid wind to get to 20 degrees at those speeds.

I ride 25mph or so in the flat and probably have never experienced 20 degrees.
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Re: Hambini's take on Zipp Dimples ROFL [burnthesheep] [ In reply to ]
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burnthesheep wrote:
Run the math on wind speeds and rider speeds for those huge yaw angles and you start to understand the charts are a bit much.

20 deg yaw? Cmon. Not to mention the forward speed used in a tunnel is 25 to 30mph. That takes a solid wind to get to 20 degrees at those speeds.

I ride 25mph or so in the flat and probably have never experienced 20 degrees.



I did an entire 40K TT @ 29MPH where I never saw less than 10 degrees. (according to BBS, grain of salt). Wind wasn't that strong either.

So the 10-15 range is valid, to me. It may be a low percentage of time overall. But when it happens the right equipment can be an enormous advantage because the drag differences are much more dramatic (the lines all bunch up around 0 degrees, but can seriously fan out past 10 degrees)

I agree that 20 degrees takes more extreme conditions, but it makes sense to run 5-10 degrees past typical to characterize performance.
Last edited by: trail: Jul 10, 20 11:34
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