Wheel Aerodynamics

[Simon Q]

http://www.rouesartisanales.com/article-15505311.html

Wheel aerodynamics showdown.

[ada@prorider.or]

http://www.rouesartisanales.com/article-15505311.html

very simple test
with very simple means

if you only look at the straingauge
very very simple

[pdxmech13]

why no new bonty stuff ?

[oldguy00]

Near meaningless to the typical rider, given that the speed tested at was 50 km/hr.
I think people would be amazed at how small the differences are between all those wheels at a more typical speed of, say, 38km/hr. I -highly- doubt there are many people on this forum, save 2 or 3, that typically average more than low to mid 30's on any ride.

[ada@prorider.or]

agree

[BumbleBeeDave]

Near meaningless to the typical rider, given that the speed tested at was 50 km/hr.
I think people would be amazed at how small the differences are between all those wheels at a more typical speed of, say, 38km/hr. I -highly- doubt there are many people on this forum, save 2 or 3, that typically average more than low to mid 30's on any ride.

It really sucks the relevancy out of the test for 95% of the people who would otherwise be interested in it, myself included. No way am I going to average 31mph on a ride unless Swoop is chasing me with a hatchet.

BBD

[brians647]

It really sucks the relevancy out of the test for 95% of the people who would otherwise be interested in it, myself included. No way am I going to average 31mph on a ride unless Swoop is chasing me with a hatchet.

BBD

Well, if that happens, just make sure you've got the right wheels!

[brians647]

Actually, just make sure you don't have the R-sys! Worst of the bunch by no small or surprising margin. :rolleyes:

[Simon Q]

very simple test
with very simple means

if you only look at the straingauge
very very simple

Maybe the watts are out but the pecking order seems about right to me: that same strain gauage was used for all wheels?

Being in the industry you may have better test data to share as I agree data points at a number of lower speeds would be interesting.

However, assuming that one's position is as aero as it can comfortably be the main other aero variable is wheel choice so wheel aerodynamics are still worth looking into IMHO:

http://www.biketechreview.com/archive/wheel_theory.htm

[Simon Q]

.

[stevep]

ditto on this.
its a nice chart. i would love to see it at 40kph/ 45kph as well.
the speed is so high that it emphasizes the aero qualities.
however , it is notable that today i pick up a new pr of carbone sls...
maybe at some point this year when not going downhill i will hit 50kph.
who knows.
a lot of rides run into 40-45kph but 50 seems elusive.

ada, how many watts different at 40k between r-sys and carbone?





Being in the industry you may have better test data to share as I agree data points at a number of lower speeds would be interesting.


http://www.biketechreview.com/archive/wheel_theory.htm

[Ti Designs]

It really sucks the relevancy out of the test for 95% of the people who would otherwise be interested in it, myself included. No way am I going to average 31mph on a ride unless Swoop is chasing me with a hatchet.

Screw the aero wheels, just yell a few insults Swoop's way while he's sharpening his hatchet and hope he doesn't learn how to throw it.

I refuse to get aero wheels. What if my wheels are faster than I am? My bike will take off down the road without me, making me look stupid (as always). Fast wheels, slow rider - bad combo!

[Registered User]

interestingly, this test actually predicted 'real' speed differences at 40kph and 35kph for 15 aero wheelsets. The fastest ones are meant to be about 1.5 kph faster at 40kph

http://www.vueltausa.com/Merchant2/graphics/00000001/media/German%20Wheel%20Test.pdf

[brians647]

Screw the aero wheels, just yell a few insults Swoop's way while he's sharpening his hatchet and hope he doesn't learn how to throw it.

I refuse to get aero wheels. What if my wheels are faster than I am? My bike will take off down the road without me, making me look stupid (as always). Fast wheels, slow rider - bad combo!


I hear you, as my bike has tried that many a time. Besides, if I have aero wheels, what can I blame for being slow?

[stevep]

you should sue the company who made the wheels that you use.
its their fault.
obviously.


I hear you, as my bike has tried that many a time. Besides, if I have aero wheels, what can I blame for being slow?

[stevep]

thats sort of it i guess.
not sure what they are comparing to but i guess the answer lies here kinda.
deeper the dish the faster... common sense i guess.

interestingly, this test actually predicted 'real' speed differences at 40kph and 35kph for 15 aero wheelsets. The fastest ones are meant to be about 1.5 kph faster at 40kph

http://www.vueltausa.com/Merchant2/graphics/00000001/media/German%20Wheel%20Test.pdf

[ergott]

I don't know about you guys, but I don't really race and I hit 33mph. This is not sustained, but if I'm going that speed, I probably really need to and I want all the help I can get. Do 20 in a 10-15mph headwind and you get the same benefits.

[Spicoli]

I dont think anyone would be too surprised by the results? I think most of the wheels finished right where you would think they'd be. The only surprise to me, and it a good one is the low profile Shimano wheels. My Brother pointed it out to me, thats pretty good for a wheel that probably spins up real fast too?

[Sasha18]

I really wish someone would throw in a low profile 32h 3x mavic or velocity wheel in these tests. I suspect it might show up about the same as those shimano wheels.

[jerk]

I really wish someone would throw in a low profile 32h 3x mavic or velocity wheel in these tests. I suspect it might show up about the same as those shimano wheels.


no it wouldn't.

jerk

[saab2000]

Please, jerk, be more clear. The ambiguity of your posts is aggrivating. Quit beating around the bush!

[zap]

I really wish someone would throw in a low profile 32h 3x mavic or velocity wheel in these tests. I suspect it might show up about the same as those shimano wheels.

I've seen tests that consistently place mavic box rims with 32 3x round spokes at the bottom of the pile then one place ahead of ksyriums, with al spokes, when they came out. Now it appears the r-sys is the newest brick, aero wise, in the bicycle wheel world.

Other than the Mavic Cosmic aero line up, the Mavic prebuilts just don't make any sense to me. I'm not much of a fan of current Mavic hubs either. I had to modify my '06 atb crossmax sl hub with the newest x pawls as the original fts-l version was getting ground down.

[Sasha18]

For the record, I'm talking about the wh-r550, which does really well in these tests for what it is. The only difference between this wheel and a conventionally spoked wheel, it seems, are the slightly lower spoke count, hidden nipples, and aero spokes (?). Is there another feature that would allow them to perform better than a chorus/ultegra hub with a reasonable spoke pattern? I can't imagine these being that big of a difference (within the scale of this test).

I rather like the Jerk's aggravating responses, but I too would like to know the logic behind this?

[my2cents]

can anyone easily/quickly identify the top 5-10 performing clinchers in the bunch?

[oldguy00]

For the record, I'm talking about the wh-r550, which does really well in these tests for what it is. The only difference between this wheel and a conventionally spoked wheel, it seems, are the slightly lower spoke count, hidden nipples, and aero spokes (?). Is there another feature that would allow them to perform better than a chorus/ultegra hub with a reasonable spoke pattern? I can't imagine these being that big of a difference (within the scale of this test).

I rather like the Jerk's aggravating responses, but I too would like to know the logic behind this?

From any reading I've done, it is in fact the lower spoke count, combined with the fact that they aren't big fat spokes like on Ksyriums, that make the shimano wheels do well in the tunnel.
Isn't that why the original shamals always did so fantastic in the tunnel, because they only had 12 spokes?

[ergott]

AC 420 is the highest ranked alloy rim. There is a Shimano carbon/alloy rim higher. The 30mm rims are all significantly more aero than the Ks

[Tobias]

Do 20 in a 10-15mph headwind and you get the same benefits.I can still hold zero speed into a 50 km/hr wind. :cool:
Not quite the same but close.

Seriously, does anyone see how the wheels are being spun while in the windtunnel? I can't see the means for spinning in the picture.

[jthurow]

I can still hold zero speed into a 50 km/hr wind. :cool:
Not quite the same but close.

Seriously, does anyone see how the wheels are being spun while in the windtunnel? I can't see the means for spinning in the picture.The wind from the tunnel makes the wheels spin.

jimi

[Tobias]

The wind from the tunnel makes the wheels spin.

jimiHow? I don't see how they control spin speed.

I'd guess the wind is moving fastest along the middle of the tunnel so it would spin the wheel, but at what rate? How is it controlled and measured?

[J.Greene]

AC 420 is the highest ranked alloy rim. There is a Shimano carbon/alloy rim higher. The 30mm rims are all significantly more aero than the Ks

Will there ever be a way to get that rim by itself? Are there any other private labels using it? After I unload my AC wheels I'll never roll on their hubs again?

JG

[ergott]

The wheel is touching a roller at the bottom.

[Simon Q]

From any reading I've done, it is in fact the lower spoke count, combined with the fact that they aren't big fat spokes like on Ksyriums, that make the shimano wheels do well in the tunnel.
Isn't that why the original shamals always did so fantastic in the tunnel, because they only had 12 spokes?

According Zipp's testing the spoke count isn't as big a factor as one would expect but that is assuming your spokes are CX Rays, not Mavic parachutes. There is a paper on it on their site. Their testing seems to reveal that it is the depth and shape of the rim that is far and away the major factor. This explains most of the results and why Zipp rims test well but perhaps doesn't explain why the low profile Shimanos do so well.

[saab2000]

FWIW, I once did a pretty long ride on some Zipp 808s. They are very deep dish and I was pleasantly surprised. I am not sure I could tell any advantage, but I also didn't notice any disadvantage, at least in terms of crosswind, etc.

There is undoudtedly an aero advantage, but for the normal rider going on normal rides I can't see having them.

That said, for racing if I were ever serious about it again I would get a set of something, very possibly Zipps.

[Tobias]

The wheel is touching a roller at the bottom.Thanks ergott. I can't see the details -- tire touching the rollers or how they are driven -- but will take your word for it.
So much depends on how the wheel is mounted, spun, and loads measured that it would be great to have some close-up pictures.