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New Enve Aero rims and some impressive SC drag numbers
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http://www.envecomposites.com/...e.pdf?20110516120258

Some good drag numbers, even better than the 808 Firecrest. I really aprecciate their approach to test the wheels with different bikes

The numbers of the SC are impressive...360grams at 13ļ of yaw

http://cds-0.blogspot.com
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Re: New Enve Aero rims and some impressive SC drag numbers [Epic-o] [ In reply to ]
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...interesting how they sort of "gloss over" the steering torque numbers...

Oh, and why a P3 instead of a P4? (edit: and why only the 3 "mid" depth wheels on the P3?)

http://bikeblather.blogspot.com/
Last edited by: Tom A.: May 16, 11 15:54
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Re: New Enve Aero rims and some impressive SC drag numbers [Tom A.] [ In reply to ]
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Tom A. wrote:
In this company, Procycling feels extremely
unintelligent and concentrates hard on
not asking stupid questions.

Not the kind of writing that gives one confidence in their reporting, huh? Still...interesting article.
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Re: New Enve Aero rims and some impressive SC drag numbers [jpb] [ In reply to ]
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Its not like many cycling publications have aeronautical engineer on staff ;-). I thought the write up was a bit better than what VN normally does and head and shoulders better than most other US based mags. Some of the German mags do a better job, mostly because they do there own testing.

Styrrell

Styrrell
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Re: New Enve Aero rims and some impressive SC drag numbers [Epic-o] [ In reply to ]
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The P3 plot is interesting. Only shows data for the 404, Stinger 6, and Enve 6.7. Granted, all wheels are roughly the same depth. I just wonder how the plot would look with the deepest wheels.

I wish the plots used a consistent symbol for the wheel depths...
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Re: New Enve Aero rims and some impressive SC drag numbers [Epic-o] [ In reply to ]
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What you can see there is that the bike itself doesn't stall at 15 degrees, but that most of the wheels do, including the new ENVE's. Seems to me like it might be worth giving up 25g of drag to the 808 Firecrest for the first 12.5 degrees in order to get back a whole lot more as it gets a bit windier...unless you are always riding 30mph and pushing the effective yaw down into the < 10 degree range.

Chris
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Re: New Enve Aero rims and some impressive SC drag numbers [Tom A.] [ In reply to ]
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I don't know about you but usually I don't use the word 'improve' to describe something that is worse.


Procycling had an exclusive early test of the

6.7 wheelset in March. That easy aero feeling

was there as we rolled along on the flat, still

chatting casually at 32kph, and during harder

efforts we found that speed clings to them like

pollen to a honey bee. Stability in crosswinds is

hard to judge without a windsock every 200m

to show you what youíre dealing with.

However, when the roadside flora and fauna is

blowing around but your bike isnít, itís clear
how the Smart Enve System improves stability



Ride Scoozy Electric Bicycles
http://www.RideScoozy.com

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Re: New Enve Aero rims and some impressive SC drag numbers [chicanery] [ In reply to ]
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except that it will add 200g of drag by being on the horns because you can't control the bike.

Ride Scoozy Electric Bicycles
http://www.RideScoozy.com
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Re: New Enve Aero rims and some impressive SC drag numbers [msuguy512] [ In reply to ]
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I can ride my SC in high wind conditions with flat sided Blackwell 100's without leaving the aerobars, so I don't think I'll have any issues with something that is designed to have reasonable crosswind sensitivity.

More importantly perhaps, riding on the horns is a lot more than 200g of additional drag unless you have a truly terrible aero position to begin with.

Chris
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Re: New Enve Aero rims and some impressive SC drag numbers [Epic-o] [ In reply to ]
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:yawn: theyve been calling their stuff aero for a long time.

more interestingly, look at the difference between the hed stingers and zipp firecrest.
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Re: New Enve Aero rims and some impressive SC drag numbers [Epic-o] [ In reply to ]
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I find it pretty questionable that they put all this stuff and can't even be bothered to mention the tire used. One important reason, as per the Velonews test, is that very often the fastest tire for aerodynamic purposes is not actually usable. I.e., the Hed S9 is fast with a 21mm tire, but you can't run that width tire on the wheel without voiding the warranty and without, in Velonew's own field testing and in others as well, damaging the rim.

The reason tire width has become especially important lately is that the latest "trick" to make a fast wheel is to increase the depth of the tire bed. This effectively brings the sidewalls way up, which makes a cleaner transition off the tire. But it also gives you that much less room for "error" if you hit rough roads. If you knowingly design a wheel this way, then you better test it with a tire you can run. Only problem is that isn't necessarily the fastest configuration.

So, HED S9 w/ 23mm tire vs. Zipp 808 with 19, 20, 21mm - whatever width you want - is the fair test. Because Zipp can take a tire as narrow as you want to put on there. But it's a bit misleading if pair the Zipp 808 with a 23mm tire because the HED S9 *needs* a 23mm tire, since the Zipp doesn't, and the Zipp is faster with a 21 than with a 23.

I'm not saying that this is the case with the ENVE wheels. But whenever tire choice - or choices - are omitted, i think that's a red flag (to me).

There are certainly some interesting design choices - like different front/rear wheels. But for a small company trying to make inroads, I question the wisdom of having six SKUs instead of three. I can certainly see that you'd be able to tune each wheel for optimal performance in the given environment, but as you can see with the Sub9 vs. the Super9, the bike you choose to put a wheel into makes a big difference as to how you optimize. The ideal rear wheel for a TT bike is going to be different than the ideal rear wheel for a road bike, especially if the road bike is a round-ish tubed bike.

Anyway, it's interesting, but as with most of this sort of stuff, it always raises way more questions than it answers...

"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp
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Re: New Enve Aero rims and some impressive SC drag numbers [Rappstar] [ In reply to ]
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Rappstar wrote:
So, HED S9 w/ 23mm tire vs. Zipp 808 with 19, 20, 21mm - whatever width you want - is the fair test. Because Zipp can take a tire as narrow as you want to put on there. But it's a bit misleading if pair the Zipp 808 with a 23mm tire because the HED S9 *needs* a 23mm tire, since the Zipp doesn't, and the Zipp is faster with a 21 than with a 23.

That would be true if 19, 20, 21 and 23mm tires had all the same rolling resistance. But if you want to compare two wheels, and see which one is faster, then you need to set rolling resistance the same. In order for that to happen, you have to compare with the same tire.

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The Triathlon Squad

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Re: New Enve Aero rims and some impressive SC drag numbers [Pooks] [ In reply to ]
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Pooks wrote:
I wish the plots used a consistent symbol for the wheel depths...

Not to mention the falsely curved lines between data points (especially noticeable on the sidewind torque graph - look at the FC404 plot! WTF?)

http://bikeblather.blogspot.com/
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Re: New Enve Aero rims and some impressive SC drag numbers [Rappstar] [ In reply to ]
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Rappstar wrote:

There are certainly some interesting design choices - like different front/rear wheels. But for a small company trying to make inroads, I question the wisdom of having six SKUs instead of three. I can certainly see that you'd be able to tune each wheel for optimal performance in the given environment, but as you can see with the Sub9 vs. the Super9, the bike you choose to put a wheel into makes a big difference as to how you optimize. The ideal rear wheel for a TT bike is going to be different than the ideal rear wheel for a road bike, especially if the road bike is a round-ish tubed bike.

Anyway, it's interesting, but as with most of this sort of stuff, it always raises way more questions than it answers...

Speaking of that, Smart is quoted as saying:
Quote:
The rim cross-sections will definitely be different because of the interaction with the bike and the flow past the rider's legs.

So...why don't we see the drag plots with bare bikes instead of with the "dummy" aboard?

They should have at least borrowed Speedplays "pedaling dummy" ;-)

http://bikeblather.blogspot.com/
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Re: New Enve Aero rims and some impressive SC drag numbers [Paulo Sousa] [ In reply to ]
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Paulo Sousa wrote:
Rappstar wrote:
So, HED S9 w/ 23mm tire vs. Zipp 808 with 19, 20, 21mm - whatever width you want - is the fair test. Because Zipp can take a tire as narrow as you want to put on there. But it's a bit misleading if pair the Zipp 808 with a 23mm tire because the HED S9 *needs* a 23mm tire, since the Zipp doesn't, and the Zipp is faster with a 21 than with a 23.

That would be true if 19, 20, 21 and 23mm tires had all the same rolling resistance. But if you want to compare two wheels, and see which one is faster, then you need to set rolling resistance the same. In order for that to happen, you have to compare with the same tire.

Just looking, for example, at AFM's most recent tire chart. You have a wide selection of tires of various widths with equivalent Crr values. And there are plenty of cases where the difference in Crr values is quite small in comparison with the the aero differences for equivalent tires of different width. The wattage difference between the new 320tpi 23mm Vittoria EVO Corsa CX and the older 21mm Corsa CX - tubular for both - is about 0.6w/wheel and that includes both width differences AND different casings. Drag differences can easily be an order of magnitude higher than between tires of that width.

You can easily test multiple width tires - with a variety of Crr values - to figure out which wheel+tire = fastest (given a range of typical speeds and yaws). It's just more work.

"Which wheel has the lowest drag" and "which wheel has the lowest drag using X tire" are NOT the same question, but too often the latter is quickly redacted into the former, especially when it suits a given company's desires.

Given the emphasis they placed on how many different rims shapes they tested, you'd think they'd have tested with a selection of different tires as well...

"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp
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Re: New Enve Aero rims and some impressive SC drag numbers [Rappstar] [ In reply to ]
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Rappstar wrote:

"Which wheel has the lowest drag" and "which wheel has the lowest drag using X tire" are NOT the same question, but too often the latter is quickly redacted into the former, especially when it suits a given company's desires.


Including Zipp. I remember one of the talking points around the 404/808 wheels when they came out was that they had a better performance for 23mm tires, which was better for RR too.

EDIT: My point here is; it seems there's an attitude here, not just coming from you, where Zipp are the fastest wheels, everyone else bring data. A similar attitude was in place some years ago regarding Cervelo and every other bike manufacturer, until it became clear that some other bikes were at the same level or better than Cervelo. I, for one, think the Enve data is solid and very encouraging.

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Last edited by: Paulo Sousa: May 16, 11 19:06
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Re: New Enve Aero rims and some impressive SC drag numbers [Paulo Sousa] [ In reply to ]
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Re: New Enve Aero rims and some impressive SC drag numbers [Paulo Sousa] [ In reply to ]
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Paulo Sousa wrote:
Rappstar wrote:

"Which wheel has the lowest drag" and "which wheel has the lowest drag using X tire" are NOT the same question, but too often the latter is quickly redacted into the former, especially when it suits a given company's desires.


Including Zipp. I remember one of the talking points around the 404/808 wheels when they came out was that they had a better performance for 23mm tires, which was better for RR too.

EDIT: My point here is; it seems there's an attitude here, not just coming from you, where Zipp are the fastest wheels, everyone else bring data. A similar attitude was in place some years ago regarding Cervelo and every other bike manufacturer, until it became clear that some other bikes were at the same level or better than Cervelo. I, for one, think the Enve data is solid and very encouraging.

I agree wholeheartedly. I think that it's one of the truly unfortunate parts of this industry (any maybe every industry) where data has become just another thing for marketing to spin.

It reminds me a lot of CPUs, where increases in clock speed were all anyone looked at. But you had big underlying differences in power consumption, multi-threading, etc. Things get even worse when magazines that have almost zero understanding of the core issues then report on the marketing. So you have suddenly removed the engineers two steps from the data. Add in a forum discussion like this, and it's three steps away.

I think there is some very cool stuff - like different front/rear shapes. Though obviously a lot of questions as well.

And there are certainly things that Zipp could do better with regards to data presentation as well. I am very willing to admit that.

Ultimately, the best wheelset is the one that is most aerodynamic, most rideable, gives you the widest options for effective tire selection, practically durable "enough," and countless other options.

What folks too often fail to realize - and companies often fail to point out because it's complicated - is that "fastest" is not universal. Fastest given criteria x, y, & z. Change the criteria, and often fastest changes. Furthermore, fastest often doesn't mean "best," or at least most practical. The Zipp Super9 being a prime example. It is, in the current premier generation of bikes, the fastest rear wheel that Zipp makes, but it's only available in a tubular. If someone doesn't comprehend how to properly glue a tire, that wheel ceases to be "the best" rear wheel, even if it is - potentially - the fastest.

I used to think presentation of data was a good thing. Now everyday I drift closer and closer to thinking that in order to be digestible to most folks, it's oversimplified to the point of almost being meaningless or, even worse, false. And if it's presented in a truly accurate form, it'd be so far over the comprehension of consumers as to be meaningless.

Everyone wants to know, "what's fastest?" And some companies try to give it to them. But the most honest answer is, most often, "it depends... On a LOT of things."

My point here is, it should be made clear what the limitations/caveats/etc. are with regards to "data." When a couple of guys who admit that their primary goal was not to appear stupid are the ones presenting the data, I don't exactly give that high marks. I'm certainly not saying Zipp is perfect. But I think they do the best job of publishing their own data (which always seems to match up with independent data, unlike some companies...) with more of the relevant data than their competitors. Could they do better? Yes. But I don't think anyone else has yet even come close to the standards that they've set...

"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp
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Re: New Enve Aero rims and some impressive SC drag numbers [Epic-o] [ In reply to ]
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A few observations...

The steering torque vs yaw graph implies that the Enve wheels suck. Even if they had it backwards, how could the 8.9 be "better" than the 3.4?

Different shapes and depths for fronts and rears. I understand the different shape part (theoretically), but not really the different depth. I guess if you are going to have different shapes though, then why not...

The rims are ~75g per rim heavier than their current light tubulars, and significantly heavier than Zipps and Heds. The 404 Firecrest set for instance is only 28g heavier than the 3.4s... and beats it on drag.
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Re: New Enve Aero rims and some impressive SC drag numbers [rruff] [ In reply to ]
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Are larger wheel builders able to source Firecrest rims yet? I have King 20/24 hubs that need to be built up...
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Re: New Enve Aero rims and some impressive SC drag numbers [Rappstar] [ In reply to ]
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Rappstar wrote:
Paulo Sousa wrote:
Rappstar wrote:

"Which wheel has the lowest drag" and "which wheel has the lowest drag using X tire" are NOT the same question, but too often the latter is quickly redacted into the former, especially when it suits a given company's desires.


Including Zipp. I remember one of the talking points around the 404/808 wheels when they came out was that they had a better performance for 23mm tires, which was better for RR too.

EDIT: My point here is; it seems there's an attitude here, not just coming from you, where Zipp are the fastest wheels, everyone else bring data. A similar attitude was in place some years ago regarding Cervelo and every other bike manufacturer, until it became clear that some other bikes were at the same level or better than Cervelo. I, for one, think the Enve data is solid and very encouraging.


I agree wholeheartedly. I think that it's one of the truly unfortunate parts of this industry (any maybe every industry) where data has become just another thing for marketing to spin.

It reminds me a lot of CPUs, where increases in clock speed were all anyone looked at. But you had big underlying differences in power consumption, multi-threading, etc. Things get even worse when magazines that have almost zero understanding of the core issues then report on the marketing. So you have suddenly removed the engineers two steps from the data. Add in a forum discussion like this, and it's three steps away.

I think there is some very cool stuff - like different front/rear shapes. Though obviously a lot of questions as well.

And there are certainly things that Zipp could do better with regards to data presentation as well. I am very willing to admit that.

Ultimately, the best wheelset is the one that is most aerodynamic, most rideable, gives you the widest options for effective tire selection, practically durable "enough," and countless other options.

What folks too often fail to realize - and companies often fail to point out because it's complicated - is that "fastest" is not universal. Fastest given criteria x, y, & z. Change the criteria, and often fastest changes. Furthermore, fastest often doesn't mean "best," or at least most practical. The Zipp Super9 being a prime example. It is, in the current premier generation of bikes, the fastest rear wheel that Zipp makes, but it's only available in a tubular. If someone doesn't comprehend how to properly glue a tire, that wheel ceases to be "the best" rear wheel, even if it is - potentially - the fastest.

I used to think presentation of data was a good thing. Now everyday I drift closer and closer to thinking that in order to be digestible to most folks, it's oversimplified to the point of almost being meaningless or, even worse, false. And if it's presented in a truly accurate form, it'd be so far over the comprehension of consumers as to be meaningless.

Everyone wants to know, "what's fastest?" And some companies try to give it to them. But the most honest answer is, most often, "it depends... On a LOT of things."

My point here is, it should be made clear what the limitations/caveats/etc. are with regards to "data." When a couple of guys who admit that their primary goal was not to appear stupid are the ones presenting the data, I don't exactly give that high marks. I'm certainly not saying Zipp is perfect. But I think they do the best job of publishing their own data (which always seems to match up with independent data, unlike some companies...) with more of the relevant data than their competitors. Could they do better? Yes. But I don't think anyone else has yet even come close to the standards that they've set...

X2

From training to transition to diet. This is gold ""fastest" is not universal. Fastest given criteria x, y, & z. Change the criteria, and often fastest changes. Furthermore, fastest often doesn't mean "best," or at least most practical...Everyone wants to know, "what's fastest?" And some companies try to give it to them. But the most honest answer is, most often, "it depends... On a LOT of things." "
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Re: New Enve Aero rims and some impressive SC drag numbers [cincytri] [ In reply to ]
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They won't sell me any, but I haven't begged either (yet).
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Re: New Enve Aero rims and some impressive SC drag numbers [cincytri] [ In reply to ]
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wheelbuilder.com is offering them

"When the going gets weird, the weird turn pro."
Hunter S. Thompson
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Re: New Enve Aero rims and some impressive SC drag numbers [rruff] [ In reply to ]
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rruff wrote:
A few observations...

The steering torque vs yaw graph implies that the Enve wheels suck. Even if they had it backwards, how could the 8.9 be "better" than the 3.4?

Different shapes and depths for fronts and rears. I understand the different shape part (theoretically), but not really the different depth. I guess if you are going to have different shapes though, then why not...

The rims are ~75g per rim heavier than their current light tubulars, and significantly heavier than Zipps and Heds. The 404 Firecrest set for instance is only 28g heavier than the 3.4s... and beats it on drag.

That's what I thought too. But after a more careful it's not the case. It's ENVE's own metric. It is *supposedly* the linearity and slope of that line which is important. Big surprise that they did the best at excelling in a metric which they created...

That graph is, roughly, the equivalent of Jeep calling all of their vehicles, "Trail Rated." Or McDonald's 100RealBeefTM. Make up some standard, and then boast that you are the only ones to meet it.

"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp
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Re: New Enve Aero rims and some impressive SC drag numbers [Rappstar] [ In reply to ]
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Rappstar wrote:
rruff wrote:
A few observations...

The steering torque vs yaw graph implies that the Enve wheels suck. Even if they had it backwards, how could the 8.9 be "better" than the 3.4?

Different shapes and depths for fronts and rears. I understand the different shape part (theoretically), but not really the different depth. I guess if you are going to have different shapes though, then why not...

The rims are ~75g per rim heavier than their current light tubulars, and significantly heavier than Zipps and Heds. The 404 Firecrest set for instance is only 28g heavier than the 3.4s... and beats it on drag.


That's what I thought too. But after a more careful it's not the case. It's ENVE's own metric. It is *supposedly* the linearity and slope of that line which is important. Big surprise that they did the best at excelling in a metric which they created...

That graph is, roughly, the equivalent of Jeep calling all of their vehicles, "Trail Rated." Or McDonald's 100RealBeefTM. Make up some standard, and then boast that you are the only ones to meet it.


I don't know...the legend of that plot does say "steering torque vs. crosswind angle". I'm thinking that's exactly what that plot represents.

On that same subject, if linearity of the response is the "be all and end all" of this subject, then why do people consider lower profile rims to be easier to handle, despite their "linearity" being "worse". For example, take a look at the plot for the 24mm deep aluminum baseline wheel...

http://bikeblather.blogspot.com/
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Re: New Enve Aero rims and some impressive SC drag numbers [Tom A.] [ In reply to ]
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Exactly. And imagine some sort of gusty wind where while it is a linear response, the amplification is huge.

Ride Scoozy Electric Bicycles
http://www.RideScoozy.com
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Re: New Enve Aero rims and some impressive SC drag numbers [Tom A.] [ In reply to ]
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Tom A. wrote:
On that same subject, if linearity of the response is the "be all and end all" of this subject, then why do people consider lower profile rims to be easier to handle, despite their "linearity" being "worse". For example, take a look at the plot for the 24mm deep aluminum baseline wheel...
I'm looking and I see that the baseline 24mm rim (and the FC 404) have better linearity than the other two (if the graph between the dots is for real).

IME (from MotoGP), linear response is crucial in all human-machine interactions that are taken to the extreme, be it throttle control, brake performance, tire grip or suspension response. When Simon Smart says that I'm inclined to nod and say "that sounds familiar".
Last edited by: Nicko: May 17, 11 13:27
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Re: New Enve Aero rims and some impressive SC drag numbers [Nicko] [ In reply to ]
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that linearity of response argument doesn't hold up though, all of the analogies are bad.

in all of those examples the human is in control of the action which then has a linear response in its effect.

in the case of a bike wheel, the human has no control over the wind. If a sudden gusts hits you, it doesn't matter if the wheels torque is linear.

similarly if the wind is a steady 10mph all day, again it doesn't matter if the response is linear.



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: New Enve Aero rims and some impressive SC drag numbers [jackmott] [ In reply to ]
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we need someone with a wind tunnel to create an "impulse gust." so we can quantify the transfer function of the "human control system."
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Re: New Enve Aero rims and some impressive SC drag numbers [jackmott] [ In reply to ]
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also while linearity of response in a race tire is good, you still pick the stickier one, usually, even if its response is not as linear. at least if you have talent =)



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: New Enve Aero rims and some impressive SC drag numbers [jackmott] [ In reply to ]
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Umm..
Sure it does.

A gust is not a step input. The side wind component goes from one level to another in a time frame that you react to. If the effect of your response changes sign or magnitude while you perform the response, all bets are off.
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Re: New Enve Aero rims and some impressive SC drag numbers [Nicko] [ In reply to ]
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as time frame approaches zero the importance of response linearity does too.

and its already starting out pretty low given that light weight women can handle all kinds of deep wheels =)


Nicko wrote:
Umm..
Sure it does.

A gust is not a step input. The side wind component goes from one level to another in a time frame that you react to. If the effect of your response changes sign or magnitude while you perform the response, all bets are off.



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: New Enve Aero rims and some impressive SC drag numbers [jackmott] [ In reply to ]
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jackmott wrote:
in all of those examples the human is in control of the action which then has a linear response in its effect.
Umm..
Believe me that the MotoGP rider is NOT in control of the highly ilinear (unlinear?) event of catastrofic tire slip from too much braking-, acceleration- and side force.
That's when the linear character of the response is crucial.

They are not "just riding along".
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Re: New Enve Aero rims and some impressive SC drag numbers [Nicko] [ In reply to ]
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the rider is in control of how much braking force is occurring, how fast he is going, and how much cornering force he is generating.

force - braking - response - slip
rider in control of braking force - not in control of slip, so linearity is good

wind force - response - steering torque

rider not in control of wind force, linearity of response less important. the wind will be stochastic to a degree anyway so what the response is will be stochastic even if the force->steering relationship is linear



Nicko wrote:
jackmott wrote:
in all of those examples the human is in control of the action which then has a linear response in its effect.
Umm..
Believe me that the MotoGP rider is NOT in control of the highly ilinear (unlinear?) event of catastrofic tire slip from too much braking-, acceleration- and side force.
That's when the linear character of the response is crucial.

They are not "just riding along".



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: New Enve Aero rims and some impressive SC drag numbers [jackmott] [ In reply to ]
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jackmott wrote:

similarly if the wind is a steady 10mph all day, again it doesn't matter if the response is linear.

I submit it does. Even if it's steady at 10mph at 12deg yaw, it's still going to require micro-input from the rider... it just seems that their shapes make for a wheel that requires less rider input. Do enough of those over the course of a five and a half hour ride and it all goes into a nice little pile called "fatigue," physical and mental.

But the real world dictates it won't ever be "steady" at 10mph. Nor will the yaw. The more the wheel can blunt the effect of each and save you from fighting the wheel, the better.

I've been testing a set of the 6.7 prototypes wheels the last few months (canyon blasts and flatland crosswinds in Borrego Springs, Calif.). Yes, you still have to control the action of canyon gusts (no argument with you there) as on any deep aero wheel. But on a "steady" crosswind day on the flats (coming off the mountain at about 18-20mph at about 18-20 degrees (it's been an effing windy spring in the Springs), I can attest to it being a pretty valuable metric. It just makes for a less worn-out rider during and after the ride. To simplify it, it's akin to taking 5mph off the crosswind, particularly up front while in the aerobars. I've not ridden Firecrest 808s yet with a 404 to compare apples-to-apples, but have been thoroughly impressed with the Enve debut.... will have a piece at LAVA pretty soon on it.

Jay Prasuhn
Marketing Specialist, American Bicycle Group (Quintana Roo//Litespeed//Obed)
twitter.com/jayprasuhn

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Re: New Enve Aero rims and some impressive SC drag numbers [jackmott] [ In reply to ]
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Sigh.
A MotoGP rider in a race does not control how fast he is going, his competitors does.
If that forces him to the limit, things turn unlinear real fast. That's when you don't want an unlinear response from your reactions.
Ideally you want the optimum/fastest driving "state" to be in a linear sub-range.
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Re: New Enve Aero rims and some impressive SC drag numbers [STJay] [ In reply to ]
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which metric? the steering torque at given wind speeds and yaw angles? I agree

the linearity of how the steering torque *changes* with yaw angle or wind speed? I disagree

STJay wrote:
I can attest to it being a pretty valuable metric..



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Re: New Enve Aero rims and some impressive SC drag numbers [Nicko] [ In reply to ]
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Nicko wrote:
Sigh.
A MotoGP rider in a race does not control how fast he is going, his competitors does..

I don't think we are having a discussion any more.



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: New Enve Aero rims and some impressive SC drag numbers [Nicko] [ In reply to ]
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Nicko wrote:
Umm..
Sure it does.

A gust is not a step input. The side wind component goes from one level to another in a time frame that you react to. If the effect of your response changes sign or magnitude while you perform the response, all bets are off.

I think I'd take a very low torque across all yaw angles (even if the slope changes sign) over linearly increasing torque that becomes MUCH larger at higher yaw angles (i.e. in gusts).

Just looking at the torque plot, I'd probably prefer the 404 Firecrest response over the Enve 6.7 response any day of the week...

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Re: New Enve Aero rims and some impressive SC drag numbers [Tom A.] [ In reply to ]
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It would be interresting to see the H3 and the 1080 in that plot.
If Mr Smart says that the linear response (and not the magnitude) is key, I believe him.
Not that it really matters to me, my H3 is completely controllable.
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Re: New Enve Aero rims and some impressive SC drag numbers [Nicko] [ In reply to ]
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and the previous version, to see this 'improvement' he speaks of

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Re: New Enve Aero rims and some impressive SC drag numbers [Tom A.] [ In reply to ]
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Speedplay could rent her pedalling dummy for other companies' aero testing, seriously

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Re: New Enve Aero rims and some impressive SC drag numbers [Epic-o] [ In reply to ]
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I'll add this, I take great pride in the data here that 2 months after we launched Firecrest technology, ENVE got serious about aero, locked in a consultant with some good aero credibility and spent 12 months and a lot of money more or less recreating almost exactly: Firecrest (further Kudos to them for making the rims in the US) Whatever that quote is about mimicry being the sincerest form of flattery holds here...I really hate that we have so quickly been followed by this and numerous others, but it really does speak to how amazing this technology truly is, we use the phrase game-changer a lot, but here it actually fits. Firecrest is the modern equivalent of the P3 wheel cuttout, it's just plain better, and everybody wants a piece, and everybody has to stake their claim to some nuance which makes them different.

Now onto the question at hand:
I am not sure how they intend for us to read the handling graph, and the wheels are not available to test, but the idea that having a shallower rim up front to improve stability has made sense forever, just as it did when we sold a 404 front/808 rear as the 606 wheelset beginning in 2004. The one I'm not sure of is the the plot of 'Steer metric' and how that plot represents more stable performance, but I do have to give credit to them for this work, and for publishing data on this. Since we launched Firecrest, 4 different manufacturers have begun touting 'Stability' as a design feature, and not one has been able to discuss how stability was improved, or what was done to improve it, there are even quite a few products that have 'stability' technologies associated with them today that are no different than they were previously, so at least Enve didn't just put a sticker on the wheel they appear to have put some thought into it.

I know that the papers written by Matt Godo of Intelligent Light have made the rounds here, you can search if needed, we worked in depth with Matt on the design of Firecrest technology, as it was his 2008 paper on wheel CFD that set me thinking about wheel stability in the first place (we have since collaborated with him on a number of papers available online). We ultimately built our own tunnel balance to replicate what we could learn from the CFD and with the Firecrest launch, really launched the idea of stability tuning for wheels...now having said all of that, once we realized we could manipulate the yaw torque, the burden on us was to figure out what was 'best'. We were able to create versions of Firecrest that had positive yaw torque (this is normal, the wheel steers with the wind), negative yaw torque (self correcting) and wheels that were very neutral...now of course, different yaw angles and different wind speeds affect this...one thing we found was that some wheels like our own 1080, the S9 and most all 3 spoke wheels would actually reverse behavior beyond some angles, so you may have positive torque to a point, and then suddenly negative beyond some wind angle...not good. From this we created ridable prototypes, basically the same plastic prototypes we've used for 10 years (just like what Enve is showing) but we developed a technique to make them fully structural...2 years ago we published a great photo of a rider riding the Firecrest prototypes in the tunnel...those aren't just plastic afterall! From that we ultimately decided that the neutral handling wheel was what people liked (as well as creating real world data sets using powermeters, but that's another story) ..and you see it in the Enve data, the 404 really does exhibit nearly identical torque response to a box section rim...and that is a very low torque, which in turn requires very little rider energy to correct. I find it ironic that Rappstar a few weeks ago told somebody that the 808 handles like the old 404 and the new 404 handles like a box section rim...it was one thing for me to agree with him, but even better to hear it from a third party! The final piece of the stability equation that we created relates to the harmonic shedding frequency of air off of the wheel...this was really the last piece of the puzzle and something that we learned our own dimples to be very beneficial for...though that was not their initial intention. This is lightly covered in the mini-documentary on Firecrest posted here: http://www.youtube.com/user/zippspeed and includes the never before seen footage of the CFD models showing the flow shedding behavior. I don't want to come across as advertising or blatant marketing, but there is some amazing stuff in there that has never before been shown. All in all, one of the coolest aspects of the Firecrest project was the sort of basic science work done with Intelligent Light, that has been published in 4 papers before the AIAA, and really has advanced the general understanding of these affects. I would post the time in the video where the CFD stuff is, but I haven't seen it as I can't stand to see or hear myself...so I welcome anybody posting that info to the thread if you'd like.

Now back to the science, as I said before, when you break ground like this, there is a real burden try and figure out what is beneficial...and then that becomes the conventional wisdom, but at the time we were learning all of this it really wasn't very obvious what should be done or even what could be done to move the center or pressure around. One thing we knew was that certain wheels just didn't handle well, and we learned that they all shared similar characteristics, high positive yaw torque (or positive yaw torque that reversed with increased wind angle) and low shedding frequencies (a few wheels showed high negative yaw torque AND low shedding frequency and that was not good either!). These shedding frequencies could get very near the natural frequency of the bike...some as low as 2 Hz..which is more or less the frequency of speed wobble! We found that the dimples help the air 'round the corner' on the trailing edge of the front half of the rim, but that the dimples in conjunction with the Firecrest shape were a real game-changer in this area, natural frequencies for Firecrest rims are generally between 20 and 40Hz, which is well above the natural frequency of the bike/rider system (in that particular axis..) and the magnitudes of the lateral forces resulting from this shedding (and consequently the torque the forces result in..) are significantly lower than in traditional systems.

Lastly, let's talk drag. Simon Smart is spot on in his assertion that the wheels will behave differently in different forks/frames, and his method of testing with different road frames and TT frames is exactly what we have been advocating and doing for some time. The problem is that if you added 4 more frames, you would have 4 more answers...these frames do not represent bookends, but are simply points along a continuum of the available frames on the market. Once you are fully optimized, the conditions are such that tweaks that make the wheels better in one frame will cost you drag in another. Same for the bike only vs mannequin, vs pedalling mannequin...you end up adding astronomical cost to learn that you ultimately have to pick between 3-4 options that could each be argued to be the best depending on what bike YOU are riding at the time (or want to show in your marketing). My guarantee is that had they tested bike only or using Speedplay's dynamic mannequin, the results would not change and no new product direction would have resulted...we have tried all of that stuff and you just end up adding a LOT of noise and uncertainty to the data and the engineers still have to make some really hard choices over what the the best compromise will be relative to the actual bikes that actual customers are likely to have... and that doesn't even mention the issue of tires, which can be every bit as large as the differences between frames!

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Re: New Enve Aero rims and some impressive SC drag numbers [joshatzipp] [ In reply to ]
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Re: New Enve Aero rims and some impressive SC drag numbers [joshatzipp] [ In reply to ]
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I agree too. Awesome post.

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