CN big aero wheel test

[aeroisnteverything]

Here is a question I have. Some of the deeper wheels (more so than others) exhibit a marked stalling behavior at high yaw angles - Scope, Vision Metron, Enve 6.7. being examples of this. Pretty clear that this is highly correlated to the wheel depth, but again, not every deep wheel is the same in this regard; shape seems to matters too - e.g., PCW 6560, which is also very deep, has a lot less of this stall at high yaw.

So which wheel would be more stable in cross winds (which is when these high yaw angles happen)? E.g., will Scope be more stable than PCW or will it be the other way around? Does anyone know?

[alanyu]

You need addional gauges to measure lateral force vs yaw. E.g, some of Tour tests show them, not all though.

[toxin]

Are you sure you know what stall means? Because from the drag plot it's the exact opposite of what you're saying, in fact it sounds more like you're talking about sailing effect, not stall

[Rabble]

Just for clarity (and as a participant in the test with our Strade wheelset), no payment was made to CN as part of taking part in the test. As a smaller business we have also never advertised with CN so I think it's fair to say we're not in any way a "sponsor".

We had a request a few weeks ago for product which we supplied, along with a comment post-test having seen the results. Having spoken a few times with the team behind the testing, I'm confident it was all carried out as thoroughly and independently as possible which is actually a very impressive exercise when you consider the scope of testing they attempted.

It might not be perfect, but I'd argue the more of these independent tests the better, for all of us - designers, brands, riders. If nothing else, the CN team are open to feedback and very willing to learn. And I commend that.

Dov-

It's great that your products were included. I'm glad that you'll get visibility here, which can only be helpful.

If you believe they did this for any reason other than expectation of future advertising potential, I would love to discuss the availability of a nice bridge which has recently been listed for sale in the New York area.


I've run a business in the racing industry for a long time. We supply championship winning teams in MotoGP, WorldSBK, NHRA, and on and on. I'm roughly familiar with how the testing articles work, having participated in them as a participant and also having helped design the test protocols for them.
The media conglomerates need manufacturers to spend money in some way in order to survive. The membership model is so new, that to believe it has displaced other revenue streams is...difficult to fathom.

[parcourswheels]

Just for clarity (and as a participant in the test with our Strade wheelset), no payment was made to CN as part of taking part in the test. As a smaller business we have also never advertised with CN so I think it's fair to say we're not in any way a "sponsor".

We had a request a few weeks ago for product which we supplied, along with a comment post-test having seen the results. Having spoken a few times with the team behind the testing, I'm confident it was all carried out as thoroughly and independently as possible which is actually a very impressive exercise when you consider the scope of testing they attempted.

It might not be perfect, but I'd argue the more of these independent tests the better, for all of us - designers, brands, riders. If nothing else, the CN team are open to feedback and very willing to learn. And I commend that.

Dov-

It's great that your products were included. I'm glad that you'll get visibility here, which can only be helpful.

If you believe they did this for any reason other than expectation of future advertising potential, I would love to discuss the availability of a nice bridge which has recently been listed for sale in the New York area.


I've run a business in the racing industry for a long time. We supply championship winning teams in MotoGP, WorldSBK, NHRA, and on and on. I'm roughly familiar with how the testing articles work, having participated in them as a participant and also having helped design the test protocols for them.
The media conglomerates need manufacturers to spend money in some way in order to survive. The membership model is so new, that to believe it has displaced other revenue streams is...difficult to fathom.

I do fully appreciate that & after 9 years running the business am well aware there's "no such thing as a free lunch" in cycling media. But I was addressing the suggestion earlier in the thread that this test was in some way sponsored by participating brands, i.e. it was "pay to play". Or that some brands were being excluded due to a reluctance to pay.

FWIW, I don't have any insight into why say a Winspace, Farsports or similar wasn't included in the test. I'd actually welcome seeing them in there but that's not my choice to make.

[TobinHatesYou]

Here is a question I have. Some of the deeper wheels (more so than others) exhibit a marked stalling behavior at high yaw angles - Scope, Vision Metron, Enve 6.7. being examples of this. Pretty clear that this is highly correlated to the wheel depth, but again, not every deep wheel is the same in this regard; shape seems to matters too - e.g., PCW 6560, which is also very deep, has a lot less of this stall at high yaw.

So which wheel would be more stable in cross winds (which is when these high yaw angles happen)? E.g., will Scope be more stable than PCW or will it be the other way around? Does anyone know?

What toxin said. The Scope, Vision, Enve, Syncros, Reserve, Parcours, etc. all had lower CdA beyond 15deg yaw vs at 15deg. The Black Inc, Princeton, SwissSide, Campagnolo, Roval and Scribe wheels all show evidence of stall beyond 15deg as their CdA ticked up.

Delayed stall is one predictor of improved control in crosswinds, but it’s not the only one.

[chrisw91]

The Scope, Vision, Enve, Syncros, Reserve, Parcours, etc. all had lower CdA beyond 15deg yaw vs at 15deg. The Black Inc, Princeton, SwissSide, Campagnolo, Roval and Scribe wheels all show evidence of stall beyond 15deg as their CdA ticked up.

I think you are mis-reading the chart. The test was only run to 15deg of yaw so we don't know how any wheels that we tested perform at higher yaw angles. The screenshot posted by Jaisen has leader lines to help identify each line on the chart. These are not data points!

[TobinHatesYou]

I think you are mis-reading the chart. The test was only run to 15deg of yaw so we don't know how any wheels that we tested perform at higher yaw angles. The screenshot posted by Jaisen has leader lines to help identify each line on the chart. These are not data points!

Okay that makes more sense. Non-data being represented as lines on a line chart is definitely a choice. But so is making everything a slightly different shade of purple I guess.

[Keykey1985]

Here is a question I have. Some of the deeper wheels (more so than others) exhibit a marked stalling behavior at high yaw angles - Scope, Vision Metron, Enve 6.7. being examples of this. Pretty clear that this is highly correlated to the wheel depth, but again, not every deep wheel is the same in this regard; shape seems to matters too - e.g., PCW 6560, which is also very deep, has a lot less of this stall at high yaw.

So which wheel would be more stable in cross winds (which is when these high yaw angles happen)? E.g., will Scope be more stable than PCW or will it be the other way around? Does anyone know?

What toxin said. The Scope, Vision, Enve, Syncros, Reserve, Parcours, etc. all had lower CdA beyond 15deg yaw vs at 15deg. The Black Inc, Princeton, SwissSide, Campagnolo, Roval and Scribe wheels all show evidence of stall beyond 15deg as their CdA ticked up.

Delayed stall is one predictor of improved control in crosswinds, but it’s not the only one.

I can kind of back this up with user experience, I've owned a set of Scribe Core 70mm and the 'equivalent' Parcours Chrono. The Scribe wheels got sketchy as crosswinds approached double digits and once into double digits they were quite a handful, to the point where they were no quicker the my LightBicycle AR56.
My Parcours in the same conditions just do not budge, I can even ride the old faithful 'puppy paws' position in winds close to 20mph.

[HiFi]

Several are hookless, currently under review:

• https://www.uci.org/pressrelease/use-of ... Q2d7bAiRy7
  https://granfondo-cycling.com/hookless-rims/

The second link (Sep24) summarizes:

• "Even though hookless rims don’t necessarily pose a safety risk when used correctly, many questions remain unanswered and it’s difficult to discern any major benefits to riders. Rather, we get the impression that certain brands are chasing greater profit margins at the cost of safety with the production of hookless rims, at least for their high-end products."

[HiFi]

There's no doubt Scope have done a good job, but the advantage of any wheel is slight before you reach the 10-15 degree band, and here Scope's advantage becomes clearer. As part of this the Scope fish scales tech is very interesting, but expensive (£4,000 wheels once you throw in ceramic bearings). Like a real fish, the size and placement of the scales may well allow tuning to a target environment. Scope's own graph (https://www.scopecycling.com/wp-content ... 6x1366.gif) strongly suggests the scales were tuned to improve performance between 10 and 15 degrees, when compared to rims w/o scales. But at both 10 and 20 degrees the two solutions are not that different. There are often competing claims about yaw angles in the real world, but Flo performed a credible analysis (https://blog.flocycling.com/aero-wheels ... lection-1/) that showed 80% of riding yaw was below 10 degrees, 14% was 10-15 degrees, and 7% was 15-20%. So in reviewing CN's +/-15 degree graphs, the significant part of the Scope advantage will apply to 14% of your ride. Scope's graph shows an advantage of 6W at 15 degrees and 0W at 10 degrees. So an average 3W advantage across the 10-15 degree band. That's a credible 3W advantage over 15% of your ride, but it does come at quite a price.

[toxin]

These are the 6.a wheels that are almost 3mm wider. The regular Artech 6 would be a bit faster still

[HiFi]

CN's tests didn't reach 20 degrees, but Scope's graph shows a 3W average saving from 10 to 20 degrees, which is (14%+7%=) 21% of your ride. However, averaging out 3W x 21% over a whole ride gives just 0.6W saving per ride, which might be less of a real-world benefit than CN's graphs might initially suggest.

[chrisw91]

Okay that makes more sense. Non-data being represented as lines on a line chart is definitely a choice. But so is making everything a slightly different shade of purple I guess.

And not a good choice in any way!

[Nereth]

Here is a question I have. Some of the deeper wheels (more so than others) exhibit a marked stalling behavior at high yaw angles - Scope, Vision Metron, Enve 6.7. being examples of this. Pretty clear that this is highly correlated to the wheel depth, but again, not every deep wheel is the same in this regard; shape seems to matters too - e.g., PCW 6560, which is also very deep, has a lot less of this stall at high yaw.

So which wheel would be more stable in cross winds (which is when these high yaw angles happen)? E.g., will Scope be more stable than PCW or will it be the other way around? Does anyone know?

What toxin said. The Scope, Vision, Enve, Syncros, Reserve, Parcours, etc. all had lower CdA beyond 15deg yaw vs at 15deg. The Black Inc, Princeton, SwissSide, Campagnolo, Roval and Scribe wheels all show evidence of stall beyond 15deg as their CdA ticked up.

Delayed stall is one predictor of improved control in crosswinds, but it’s not the only one.

As I'm sure you're aware though, it's not on it's own a great predictor - as long as the stall doesn't happen, the side force just keeps on rising. It drops once the stall happens and that's a lot worse if it's built up much higher first. If it's going to stall, then you would want it to stall early for stabilities sake. Unfortunately, that's also slower. No free lunch.

Furthermore, the deeper wheels which typically delay stall longer, also tend to generate more side force per unit of lateral wind speed. Me riding around on an 80mm front wheel in strong/smooth cross wind down our coast here, gets pretty egregious if they don't stall. I find myself noticeably pushing forward with my right hand for 10 minutes straight to keep the wheel pointed straight, to the point it is fatiguing