Login required to started new threads

Login required to post replies

Prev Next
Updated: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout
Quote | Reply
Update: the link below has been updated with significantly more information with regards to protocol, etc. I've included an interesting quote below
https://www.hambini.com/...which-one-is-fastest

Quote:
The testing that has been carried out is usually steady state. A steady state analysis assumes the wheels, bike and rider are in a nice environment where air is hitting them at a perfect speed and perfect angle. The drag is then recorded.
In the real world, very few riders have the ability to maintain a speed of 50km/h for a length of time as they are simply not fit enough. The reality is on the open road, wind does not come in from a perfect angle, it's speed changes and things like street furniture (hedges, kerbs, passing cars, rider rocking from left to right) upset the airflow over the rider. Modeling this type of situation is called transient analysis. It is technically more difficult to carry out transient analysis both in CFD and in a wind tunnel. Most wind tunnels are not geared up to carry out transient analysis.
Wheel manufacturers are now using a weighted analysis of yaw angles and speeds to give an overall rating for their wheels. Bare in mind they can adjust their weighting to make their wheels look better!
A superior method of analysis is to carry out a transient analysis in a wind tunnel. This requires a wind tunnel with Horizontal and Vertical Louvres to add Swirl to the air before it hits the bike and rider. This allows a much more realistic estimate of drag to be estimated as it simulates road conditions.


My notes:
  • There isn't a ton of information on the "protocol" i.e. what yaw distribution was used. (scratch that, now included)
  • There is some illusion made by the author to measuring "transient drag" instead of "steady state" drag.
  • No tire information is given (scratch that, now included)
  • The power differences between 30 km/h and 50km/h look about right
  • Other than the occasional oddball, the ordinal rankings look about right based on depth.
  • I'm guessing the "Bontrager 60mm" are the new Aeolus XXX 60mm rims as the D3 profile was not offered in a 60mm depth.
  • I find it interesting that both the Bontrager and the (presumably) Aeolus XXX performed so well. They are both very similar in shape which is a somewhat "new" shape. I tend to believe the data that Trek Bontrager produces so that gives me some confidence in the ordinal results shown here.
  • Flo wheels did not do well in this test which makes me wonder which version of their wheels were tested. The 45 is obviously the carbon model.

...I'll go get my popcorn.



Last edited by: GreenPlease: Aug 31, 18 13:30
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
Yeah...tires used can be important. Remember, the Flo wheels were designed around Conti GP4000SII tires (edit: 23C as I recall)



http://bikeblather.blogspot.com/
Last edited by: Tom A.: Aug 20, 18 14:06
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
Hahaha, I presume they didn't realise that the Shimano C50 and C60 are actually the exact same wheel with a different sticker on it?! At least their testing protocol appears robust on that basis...
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [awenborn] [ In reply to ]
Quote | Reply
awenborn wrote:
Hahaha, I presume they didn't realise that the Shimano C50 and C60 are actually the exact same wheel with a different sticker on it?! At least their testing protocol appears robust on that basis...

LOL! I didn't know that! That's a surprising control 😂
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
Jim has stressed that tire choice is critical with the Enve 7.8 and that wheel needs a 25c tire. I think he had to pull out some tricks in order to get the 7.8/25c combo to work in a P5 IIRC. While not 100% clear, the test description seems to indicate a 23c tire was used with all wheels.

More than that, it seems they tested in a rider position described as "relaxed hoods." Without using aero bars to help lock in consistent position, this would seem to introduce additional error.

Then again, the C50/C60 data are impressive, unless... [Cue Larry David voice] it was an "accidental text on purpose"

Race Director, Velo Club La Grange (http://www.lagrange.org)
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099
Last edited by: refthimos: Aug 20, 18 15:52
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [Tom A.] [ In reply to ]
Quote | Reply
Tom A. wrote:
Yeah...tires used can be important. Remember, the Flo wheels were designed around Conti GP4000SII tires (edit: 23C as I recall)

The first-gen ones most definitely were not.

FLO initially recommended Michelin Pro 4 Comp tires which I bought. Then they tunnel-tested GP4000s tires which tested better. Anyone want to buy a Michelin Pro 4 Comp?

-------------------
Madison photographer Timothy Hughes | Instagram
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
who in the hell needs areo wheels to go 50kph on 583w???? let's get the numbers down to realistic values before making comparisons. I assume the rider had a small parachute attached
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [refthimos] [ In reply to ]
Quote | Reply
Think about the “meta” of the C50/C60 data though... are they banking on someone knowing it’s the same wheel so they say “hey, look at that, the same wheel tested the same, it must be repeatable.” Seems like a stretch. I spend an unhealthy amount of time on this stuff and I didn’t know that.

I’m genuinely curious about the 7.8. The idea of having a 25mm tire (likely 27 mm measured) is appealing especially if you were to run something like the Corsa Speed 5-10psi lower than normal.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
The new Bontrager XXX wheels come in a "2", "4", and "6" version that are 28, 47, and 60 mm deep respectively. So there is no XXX version that is 50 mm deep. I would be curious to know exactly what wheels were tested because I was mildly looking at the XXX4. Still not convinced I want to go carbon braking surface but my old 404 aluminum clinchers are starting to act up. Interesting that they didn't test any of the HED wheels.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [refthimos] [ In reply to ]
Quote | Reply
refthimos wrote:
Jim has stressed that tire choice is critical with the Enve 7.8 and that wheel needs a 25c tire. I think he had to pull out some tricks in order to get the 7.8/25c combo to work in a P5 IIRC. While not 100% clear, the test description seems to indicate a 23c tire was used with all wheels.

More than that, it seems they tested in a rider position described as "relaxed hoods." Without using aero bars to help lock in consistent position, this would seem to introduce additional error.

Then again, the C50/C60 data are impressive, unless... [Cue Larry David voice] it was an "accidental text on purpose"

My reading of it was there were 2 phases of testing. The first phase was outdoors riding that was gathering data on yaw angles and transients. The second phase was wheel tests in a wind tunnel using the data gathered in phase one, with the main difference in this testing as compared to typical tests being the transient emphasis.

The results of phase 2 are then presented as a "distilled" single number prediction of an all-up drag number for a complete bike+rider system...at least that's the gist I'm getting. But, as I said, not totally clear...



http://bikeblather.blogspot.com/
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [Tom A.] [ In reply to ]
Quote | Reply
That’s my impression as well. It’s a shame more information wasn’t given on the protocol as the results are interesting and it seems like they came up with a higher yaw distribution than we’ve become accustomed to.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [Jason N] [ In reply to ]
Quote | Reply
Jason N wrote:
The new Bontrager XXX wheels come in a "2", "4", and "6" version that are 28, 47, and 60 mm deep respectively. So there is no XXX version that is 50 mm deep. I would be curious to know exactly what wheels were tested because I was mildly looking at the XXX4. Still not convinced I want to go carbon braking surface but my old 404 aluminum clinchers are starting to act up. Interesting that they didn't test any of the HED wheels.

He confirmed in a comment that they're the XXX.

I suspect people didn't read the text closely and skipped to the charts, he says "The rim depths are split into classes to make it easier for comparison, they may not agree with the stated size from the supplier."


The Shimano C60 is also marked (50mm). Whether that means he tested them separately or not is a "who knows".

The point is, ladies and gentleman, that speed, for lack of a better word, is good. Speed is right, Speed works. Speed clarifies, cuts through, and captures the essence of the evolutionary spirit.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
I am not sure what can be learned from such incomplete data. Yaw angle is obviously a huge factor, which model 808 and 404? Which hubs? What fork were these on and at what blade width? What happened to Hed and Profile Design?
There are simply way too many unknowns to draw any conclusions.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [Jason N] [ In reply to ]
Quote | Reply
Jason N wrote:
The new Bontrager XXX wheels come in a "2", "4", and "6" version that are 28, 47, and 60 mm deep respectively. So there is no XXX version that is 50 mm deep. I would be curious to know exactly what wheels were tested because I was mildly looking at the XXX4. Still not convinced I want to go carbon braking surface but my old 404 aluminum clinchers are starting to act up. Interesting that they didn't test any of the HED wheels.
Yeah it doesn't seem to be "comprehensive" without the Hed's (often the fastest).

On the XXX4, they actually brake pretty well - light years better than the old Aeolus', where you pretty much had to pray. Haven't ridden them in the rain though.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
So I read this as a don't buy FLO...

Rugby Media Dude-earfulofdirt.com

Hooker training for the Sport of Scrum-Halves [Triathlon]
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [TheStroBro] [ In reply to ]
Quote | Reply
Certainly not a great showing here. That said, Flo has always been very transparent with their testing data and their wheels have tested fast elsewhere (TomA's data comes to mind). So I think we need significantly more information about how this test was set up.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [Tom A.] [ In reply to ]
Quote | Reply
Tom A. wrote:
Yeah...tires used can be important. Remember, the Flo wheels were designed around Conti GP4000SII tires (edit: 23C as I recall)

Can't just be designed around a tire though... we need a tire and PSI and whether it has been a tire sitting and holding air for 3 weeks or brand new. ***partially in pink***


Save: $20 on Air Relax Recovery Boots| $100 on Normatec| 15% on The Most Absorbable Magnesium | Best $50 Indoor Cycling Desk

Blogs: 2018 Normatec Pulse vs 2015-2017 Normatec Pulse | QUICK Air Relax Travel Case Review | Q1 2018 Blood Test Results | Why Latex Bikes Tubes | Vittoria Corsa Speed Aero Data | 10 Reasons To Consider HED JET+
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [refthimos] [ In reply to ]
Quote | Reply
refthimos wrote:
Jim has stressed that tire choice is critical with the Enve 7.8 and that wheel needs a 25c tire. I think he had to pull out some tricks in order to get the 7.8/25c combo to work in a P5 IIRC. While not 100% clear, the test description seems to indicate a 23c tire was used with all wheels.

More than that, it seems they tested in a rider position described as "relaxed hoods." Without using aero bars to help lock in consistent position, this would seem to introduce additional error.

Then again, the C50/C60 data are impressive, unless... [Cue Larry David voice] it was an "accidental text on purpose"

Over and over and over again I've found the same results...if you don't test the 7.8 with a 25c tire, you haven't tested it properly. Tire choice and pressure is absolutely crucial to any wheel testing and, for that reason, it's practically impossible to conduct a test like this properly. If you try to make the testing "fair" by using the same tire and pressure for each wheel, you've likely produced near meaningless data. There are simply too many variables; it would take weeks to test all the different combinations. Then, of course, you'll need to repeat those results to give them value. Fun!

Jim Manton / ERO Sports

"It's not about longer, or lower, or tilted, or not tilted. It's about getting smaller. Let the wind see as little of you as possible in the best way you can."

Aero Tidbits posted on Instagram & Facebook
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
Seems to contradict my test with the flo 60 vs the 808 and 404 which it beat by a good chunk. All with a 23 supersonic.
Added to that it was the front of a p4 which has a narrowish fork. So maybe that’s a factor.
Last edited by: TriByran: Aug 21, 18 0:47
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [Jim@EROsports] [ In reply to ]
Quote | Reply
Ultimately though, people just want the fastest wheel/tyre combination. If you wanted to know the outright fastest complete wheel system, why can't a list of wheels simply be tested in the purported 'fastest configuration'?

____________________________________________
"Nobody wants to be themselves anymore. Internet, social media, goddamn talent shows for a**holes… Everybody wants to be somebody else. Nobody is happy just to look at themselves in the mirror, see themselves"
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [Jim@EROsports] [ In reply to ]
Quote | Reply
Whenever this topic comes up I always think we should view the wheel + tyre as a system. Test each wheel with the very best tyre that the manufacturer can recommend, or which has been shown in testing to work best with that wheel.

I mean, the idea of the thing is to find out how to go as fast as possible so just test everything in its fastest configuration.

If the manufacturer cannot recommend the tyre that works best with their wheel, or no additional test data is available, then screw 'em they can have a 28 on there as punishment because if they are trying to sell something to us based on its aerodynamic merit then they should have learned this by now, and be able to provide an answer.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [lanierb] [ In reply to ]
Quote | Reply
lanierb wrote:
On the XXX4, they actually brake pretty well - light years better than the old Aeolus', where you pretty much had to pray. Haven't ridden them in the rain though.

For the "old Aeolus" do you mean the Aeolus Pro 5 and similar? This one:

https://www.trekbikes.com/...colorCode=black_grey

If so, that's disappointing, because that price had been tempting me for a while.

The point is, ladies and gentleman, that speed, for lack of a better word, is good. Speed is right, Speed works. Speed clarifies, cuts through, and captures the essence of the evolutionary spirit.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [IntenseOne] [ In reply to ]
Quote | Reply
IntenseOne wrote:
I am not sure what can be learned from such incomplete data. Yaw angle is obviously a huge factor, which model 808 and 404? Which hubs? What fork were these on and at what blade width? What happened to Hed and Profile Design?
There are simply way too many unknowns to draw any conclusions.

It's been a few years, but I'm pretty sure this was the exact same opening and closing line for my thesis defense.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
GreenPlease wrote:
..... I think we need significantly more information about how this test was set up.
Yep, there's a lot I'm not clear on including how they gathered the data to generate the transient template and whether or not this took airflow velocity gradient into account (i.e. did they measure airflow magnitude and direction at a single height above the ground or did they do a sweep from the ground up - which would be very difficult to do well, I suspect. This is a pretty fundamental factor.
Also, is the wheel rotation mapped directly against airspeed, or does it take account of the fact groundspeed and airspeed (however that's measured) will not be the same except when travelling in a homogeneous body of still air - which is not what the test is about.
Quote Reply
Re: A Comprehensive (But Controversial) Wind Tunnel Wheel Shootout [GreenPlease] [ In reply to ]
Quote | Reply
GreenPlease wrote:
https://www.hambini.com/...which-one-is-fastest

My notes:

  • There isn't a ton of information on the "protocol" i.e. what yaw distribution was used.
  • There is some illusion made by the author to measuring "transient drag" instead of "steady state" drag.
  • No tire information is given
  • The power differences between 30 km/h and 50km/h look about right
  • Other than the occasional oddball, the ordinal rankings look about right based on depth.
  • I'm guessing the "Bontrager 60mm" are the new Aeolus XXX 60mm rims as the D3 profile was not offered in a 60mm depth.
  • I find it interesting that both the Bontrager and the (presumably) Aeolus XXX performed so well. They are both very similar in shape which is a somewhat "new" shape. I tend to believe the data that Trek Bontrager produces so that gives me some confidence in the ordinal results shown here.
  • Flo wheels did not do well in this test which makes me wonder which version of their wheels were tested. The 45 is obviously the carbon model.

...I'll go get my popcorn.



Bunch of horseshit test by Yoeleo , they finally figured out how to market/move their stock. They use to have YT channel with some chick talking/showing their frames and wheels... It was painful to watch, but with 500-600$ for set of wheels/frame people were watching.


They describe testing protocol without reviling testing protocol...relaxed hoods at 50km/h who was doing this test in UK ? Wiggo, Mr G or Froome?


You can't go wrong with those prices if you are on the budget, I just don't understand why people need validation from some BS test, like few watts would matter. You want to show off in front of friends: envy and zipp, no $, and want to lie to yourself you are faster get Yoyo.

If I offended anyone I'm sorry, I just call it how i see it.
Quote Reply

Prev Next