# Reality check...Are aero-looking wheelsets REALLY more aero?



## patchito (Jun 30, 2005)

There's really no way to objectively compare wheels for their Coefficient of Drag, so are all of these pre-built, really high tech-looking wheelsets really an improvement, or are they just an example of highly effective marketing to bike geeks who simply have to have the trickest looking baubles hanging off of their fashionably boutique frames? 

Take the Ksyriums for example, the ubiquitous must have wheelset for roadies with some money to burn. I've gotta hand it to Mavic for moving beyond just selling rims and creating a whole new high margin product category that's now flooded with comptetitors. The cynic in me, though, wonders if the primary advantage of the Ksyriums isn't that they just look cool.

Any place like the Weight Weenies website to compare wind drag on different wheelsets or stiffness between different wheelsets?


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## Koop (Oct 23, 2005)

patchito said:


> Take the Ksyriums for example, the ubiquitous must have wheelset for roadies with some money to burn. I've gotta hand it to Mavic for moving beyond just selling rims and creating a whole new high margin product category that's now flooded with comptetitors. The cynic in me, though, wonders if the primary advantage of the Ksyriums isn't that they just look cool.


I don't know about drag coefficient, but I love my Ksyrium SSC-SL's because:

1) They're bullet proof. 2,500+ hard miles and still running true.

2) They rail through the corners. These wheels transform a bikes cornering ability compared to lesser wheels I've used.

I didn't buy them for their aero characteristics. In fact, in a stiff cross wind the bladed spokes probably hinder more than they help. Are they worth the money? I dunno, I'm sure there are alternatives but I don't regret buying them.


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## Marc (Jan 23, 2005)

Most sources I've come across agree that rim sections really don't start providing aerodynamic benefit until at least 30mm of rim depth-some say 50mm some say 40--depends on who you ask


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## asgelle (Apr 21, 2003)

Room 1201 said:


> Most sources I've come across agree that rim sections really don't start providing aerodynamic benefit until at least 30mm of rim depth-some say 50mm some say 40--depends on who you ask


I don't know who your sources are, but there is plenty of empirical and theoretical data showing that increasing rim depth at any depth lowers wheel drag. The question is only what the magnitude of the benefit is. For example, http://www.zipp.com/tech/documents/ANoteonRimWidth_002.pdf


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## Under ACrookedSky (Nov 8, 2005)

asgelle said:


> I don't know who your sources are, but there is plenty of empirical and theoretical data showing that increasing rim depth at any depth lowers wheel drag. The question is only what the magnitude of the benefit is.


So why don't you break it down for us and tell us what benefit we'll see by switching from Open Pro rims to a 30 mm rim while riding at 20 mph?

My vote is that 30 mm rims fall somewhere in between marketing hype and scam.


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## asgelle (Apr 21, 2003)

Under ACrookedSky said:


> So why don't you break it down for us and tell us what benefit we'll see by switching from Open Pro rims to a 30 mm rim while riding at 20 mph?
> 
> My vote is that 30 mm rims fall somewhere in between marketing hype and scam.


Because I'm busy and have no desire to do the calculations again. You can search the forum and find the answer there. Or else you can just look at the data at http://www.zipp.com/tech/documents/...imWidth_002.pdf

On the other hand, can you quantify the benefit at the "hype" and "scam" levels. That way we can compare to actual wind tunnel data to see if your vote is correct.


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## euro-trash (May 1, 2004)

Under ACrookedSky said:


> So why don't you break it down for us and tell us what benefit we'll see by switching from Open Pro rims to a 30 mm rim while riding at 20 mph?
> 
> My vote is that 30 mm rims fall somewhere in between marketing hype and scam.


30 mm are not a SCAM, they are a tradeoff, like everything else. Extra weight verses a little bit of aero benefit. If we're talking Aluminum 30 mm rims verses Open Pros, a weight difference of about 100 grams is what I'd expect. It probably isn't worth it at 20 mph. At 26mph, if you aren't climbing or accelerating a whole lot maybe it's worth it, that's where you need to look at site like analyticcyclist.com


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## alienator (Jun 11, 2004)

Now you might be advised to take this with a grain of salt, but I thought I heard that Ksyriums were aerodynamically kack. Just what I heard.

As for rim depth....first, aero effects don't come into play like a light switch, so it's not as if at 50+mm they work and below they don't. At the same time, the governing equations are not linear, so if a wheel w/ a 50mm rim has a CD of X, the same wheel w/ a 25mm rim won't have a CD of 0.5X.

It is safe to assume, however, that there is a lot of hype surrounding wheels and their aero properties.


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## SDizzle (May 1, 2004)

Under ACrookedSky said:


> My vote is that 30 mm rims fall somewhere in between marketing hype and scam.


Clearly, you don't produce enough power to notice the extra stiffness provided by a deeper (and heavier, and probably not any more aerodynamic than an OP) section rim. A 30 mm rim is noticeably stiffer than an its shallower cousin. I can tie an OP up like a pretzel, though it's admittedly one of the stiffer 20 mm rims.


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## MikeBiker (Mar 9, 2003)

asgelle said:


> Because I'm busy and have no desire to do the calculations again. You can search the forum and find the answer there. Or else you can just look at the data at http://www.zipp.com/tech/documents/...imWidth_002.pdf
> 
> On the other hand, can you quantify the benefit at the "hype" and "scam" levels. That way we can compare to actual wind tunnel data to see if your vote is correct.


The PDF file evidently has been moved.


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## poshscot (Dec 14, 2004)

*if you really want to know theres an easy test you can all try...*

put a standard 32 spoke rear wheel on your bike and then do five minutes in top gear on your turbo,

then swap for an aero wheel (in my case a 16 spoke shamal) and do the same again.

i utterly guarantee you will feel a significant difference.

anyone who says otherwise either hasnt tried it or is lying.


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## alienator (Jun 11, 2004)

poshscot said:


> put a standard 32 spoke rear wheel on your bike and then do five minutes in top gear on your turbo,
> 
> then swap for an aero wheel (in my case a 16 spoke shamal) and do the same again.
> 
> ...


This won't tell you anything. Aero profiled rims are a benefit when the bike is in motion, not when the bike is stationary.


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## asgelle (Apr 21, 2003)

MikeBiker said:


> The PDF file evidently has been moved.


Try http://zipp.com/tech/aero.shtml then click on the "A note on rim width.pdf" At least that works for me.


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## MikeBiker (Mar 9, 2003)

asgelle said:


> Try http://zipp.com/tech/aero.shtml then click on the "A note on rim width.pdf" At least that works for me.


Thanks, that worked.


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## poshscot (Dec 14, 2004)

alienator said:


> This won't tell you anything. Aero profiled rims are a benefit when the bike is in motion, not when the bike is stationary.


of course it makes a difference - there is less resistance in turning the pedals. 

'aero' is not just about the bike cutting through the air in forward motion there is the 'egg beater' effect. 

at the same time as the bike is moving forward through the air, the wheel is also turning within the frame. the more easily the wheel turns within the frame the less effort required to turn the pedals at the same speed. it is just the same as having the smoothest running wheel bearings - it requires less effort to turn the pedals. 


add the effect felt whilst on the turbo to the effect of forward motion and yes - aero wheels deffinately make a difference.

seriously - dont take my word for it, go try it.


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## asgelle (Apr 21, 2003)

Your test fails for two reasons. First, you're not controlling for spoke count. Especially in your test, the number of spokes will play a much larger role than the rim depth. Second, the apparent wind in your test is nothing like the wind while in motion. You only have the circumferential flow in your test. On the road, there will be a horizontal flow equal to the vector sum of the bike speed and true wind.


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## poshscot (Dec 14, 2004)

asgelle said:


> Your test fails for two reasons. First, you're not controlling for spoke count. Especially in your test, the number of spokes will play a much larger role than the rim depth. Second, the apparent wind in your test is nothing like the wind while in motion. You only have the circumferential flow in your test. On the road, there will be a horizontal flow equal to the vector sum of the bike speed and true wind.


firstly, i thought that a reduced spoke count applied to a deep section rim is what defines an aero wheel.

secondly, are you therefore telling me that the horizontal flow equal to the vector sum of the bike speed and true wind cancels out the benefit of the reduced circumferential flow of an aero wheel over a standard?

infact the link you posted earlier actually has a note regarding this that states:

Wattage to Spin

The drag graphs bring us to the next major point with aerodynamic wheels, wattage required to spin the wheel in the airflow. The drag of the wheel is only one component of the spinning wheel system, with the other being the wattage (power) required to spin that wheel during the test. Simultaneous to all of this wheel testing, the wattage requirements are being measured and recorded in a second set of graphs, and the information hidden within can be quite revealing, or quite perplexing depending on the situation. Much of the information on wattage to spin is also contained in A Note on Spoke Shape Utilized in Aerodynamic Bicycle Wheels, but we will drop the graph in below to help highlight the spoke count issue as well. Since our testing on spoke count contains data solely pertaining to change in spoke count of a wheel with all other factors remaining constant, the graph below becomes quite interesting and a bit perplexing at the same time. Of note is that the 18 spoke wheel seems to require fewer watts to spin than the 16 spoke wheel, and the 28 spoke wheel requires only 4 more watts to spin at its worst data point. The answers here are similar to those found in the aerodynamic graphs on this topic in that they relate to margin of uncertainty. The wattage test has a higher uncertainty than that associated with the wind tunnel balance, in fact, the uncertainty is roughly 4 watts, so in order to make really valid conclusions we should really have a minimum of 7 runs averaged for each spoke count before we could even begin to compare the data statistically. The reality is that the wheels seem very similar in performance because they are, and whatever differences exist are quite small (less than +/-2 watts). The more traditional wheels on the other hand, so show some large differences between them, with the 20 bladed spokes being more than 10 watts more efficient than the 32 round spokes.


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## alienator (Jun 11, 2004)

poshscot said:


> firstly, i thought that a reduced spoke count applied to a deep section rim is what defines an aero wheel.
> 
> secondly, are you therefore telling me that the horizontal flow equal to the vector sum of the bike speed and true wind cancels out the benefit of the reduced circumferential flow of an aero wheel over a standard?


Reduced spoke count is not necessarily an aero benefit. I'm fairly certain that Rolf wheels don't do that well in aero tests. The aerodynmics of the wheel interior is more complex, a combination of spoke number, spoke profile, spoke spacing, the dynamics of the flow coming off the bike/rider combo, and the relative wind.

Second, air flow off the spokes is going to be turbulent so I don't think an aero rim will improve that condition at all. An aero rim is aero to deal with the relative wind. 

Also, your test neglects the effects of the frame/rider on air flow incident on the rear wheel.


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## wipeout (Jun 6, 2005)

alienator said:


> This won't tell you anything. Aero profiled rims are a benefit when the bike is in motion, not when the bike is stationary.


Not entirely true, the spokes are shorter - less area to beat the air.


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## flying (Feb 17, 2004)

It was quite awhile ago but what seemed important to me when the aero started up was........At what speed does it actually help.
This is just from memory but I thought it was closer to 30 mph that the benefits really showed.
So unless it is a TT in a fairly flat area I thought hmmmm
Recently I bought a Cervelo R2.5 It has the 30mm Eastons. Not great wheels I know. But the biggest thing I notice is it is affected by cross winds quite a bit.
All of my rides involve climbing at least 1-2000' so Aero is not that critical for me but I sure have noticed the wind 

I have also often wondered why carbon climbing wheels like the Zipp 303 are so aero in shape?


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## asgelle (Apr 21, 2003)

flying said:


> It was quite awhile ago but what seemed important to me when the aero started up was........At what speed does it actually help.
> This is just from memory but I thought it was closer to 30 mph that the benefits really showed.


The aero benefit itself is pretty much independent of speed at normal cycling speeds. What that means is if one wheel has 10% lower drag at 30 mph, it will also have 10% lower drag at 10 mph or 40 mph. What changes is the contribution of drag to the total power requirement to move the bike. At low speeds, rolling resistance and frictional losses have a larger relative role than at higher speeds. The exact values can be estimated using one of the models at sites such as analyticcycling.com


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## asgelle (Apr 21, 2003)

poshscot said:


> secondly, are you therefore telling me that the horizontal flow equal to the vector sum of the bike speed and true wind cancels out the benefit of the reduced circumferential flow of an aero wheel over a standard?


It's a real stretch to read that into what I wrote. I wrote that you are neglecting the horizontal flow and that is an important component to the total drag. I never said anything about the relative value of the circumferential flow.



poshscot said:


> infact the link you posted earlier actually has a note regarding this that states:
> 
> Wattage to Spin
> 
> The drag graphs bring us to the next major point with aerodynamic wheels, wattage required to spin the wheel in the airflow. The drag of the wheel is only one component of the spinning wheel system, with the other being the wattage (power) required to spin that wheel during the test.


Well that pretty much supports what I wrote doesn't it. There are two components and you only consider one.


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## flying (Feb 17, 2004)

asgelle said:


> The aero benefit itself is pretty much independent of speed at normal cycling speeds. What that means is if one wheel has 10% lower drag at 30 mph, it will also have 10% lower drag at 10 mph or 40 mph. What changes is the contribution of drag to the total power requirement to move the bike. At low speeds, rolling resistance and frictional losses have a larger relative role than at higher speeds. The exact values can be estimated using one of the models at sites such as analyticcycling.com


Makes sense to me 
You know thinking back I bet I was thinking of bladed spokes. Where I read about the benefits coming at higher speeds.
Still with the exception of TT's O wonder if it is worth the hassle if you live in windy areas like I do. The crosswinds make it quite a handful at times.


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## djg (Nov 27, 2001)

*There are ways to objectively compare wheels; what's*

harder is picking the objective test that's most usefully applied to the conditions under which the wheels will be used, especially if those conditions are highly varied.

Certainly, folks have doe wind tunnel testing on different wheels and they're not all equal. I'm sure others will post links to various models and data sets you can play with.

A 30 mm rim is not much taller than a traditional box section rim and may, or may not, under given conditions--and depending on other features of the rim and wheel--confer any significant aero advantage. It seems to me that "semi-aero" is a basically meaningless term that gets applied to all sorts of rims and wheels as a marketing label. That doesn't mean that something like a CXP-33 rim, or a K rim, or a Velocity Deep V rim doesn't have a legitimate application. That application may have rather little to do with shaving seconds of a TT result, however.

As for Ksyriums: you may or may not like them and you may or may not find them worth the price (which can vary tremendously, depending on how, and where, you obtain them). I've had a set of the Ksyrium SSCs for a while now, and I've talked to others who've tried Ks, and it seems to me that their virtues are real even if you don't glean any aero advantage from the rim profile and spokes. Ks have, IMO, great hubs and are respectably light (albeit not ultralight) wheels that are very sturdy, very dependable, and laterally rigid. Folks who like them like the way they roll, the way they corner, and they way they hold up. Folks who don't complain about various things. But most of their fans don't seem to mistake them for Zipp 404s or Reynolds Stratus or any other deep section wheel. I'm glad I got mine, even though I don't consider them the ne plus ultra wheel for all conditions, and even though I didn't pay (and likely would have balked at) anything close to the retail price for them.


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## alienator (Jun 11, 2004)

wipeout said:


> Not entirely true, the spokes are shorter - less area to beat the air.


Yeah, well, I think you knew what I meant. You can get shorter spokes with a 50mm tall box section rim, too. The aero, part, though of the aero rim, is what I was talking about.


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## Gnarly 928 (Nov 19, 2005)

*The Data I found says "Yes, most certainly" ()long post)*

I don't have links to all the sources I found during my recent 'research' on just this very topic, but after a few weeks of Googling "bicycle aerodynamics""Bike wheel aerodynamics", etc. etc. every study I found shows a significant aero edge for all those "Gucci wheels" The best(most comprehensive) write up I found was from a Euro magazine, I wish I could cite a name but I've forgotten what it was or where I found it, exactly. It agreed with what all the other studies and aero/wind tunnel testing says, but this study had no 'vested interest' that I could discern. The makers of these wheels(Zipp, Reynolds, FSA, Cane Creek, HED, etc) all post their own 'test' data showing *their* product to be the most aero..If you get past all that and look at as many different sources as you can find, they all show data that agrees, in essence. It indicates Aero wheels are indeed, very much more efficient.
This is from memory, but the Euro-Mag. test did about 20 different makes and configurations of wheels. They used a wind tunnel and a roller to turn the wheel, and somehow measured the drag of each at various angles to the wind. They limited the published results of the testing (for brevity, I guess) to what a given wheel would do in a 40k time trial at a speed of 20mph.(Coinciding with an event distance and speed that I recently did).There are all kinds of different measurments in the study, but the main one that meant something to me was: Given the same distance and the same amounts of watts of energy..they somehow tabulated the amount of time you would save using each wheel over their " base" wheels:--Mavic Ksyriums. If I recall correctly, the Mavic Ks were significantly more efficient than a 32 spoke box rim, which they didn't even bother with in the tables, after they showed to be so much 'slower" than even the Ksyriums, which were very slow, indeed..compared to most of the "slick, Gucci, Unobtanium-priced" wheels. This was a racer mag. so they assumed that no one would ever race on regular wheels any more, hence they didn't test the box rims. I hear that Mavic no longer even makes the Open Pro rim..no demand in Europe..
A few numbers, again from memory. Some conservative Aero wheels like the Zipp 303s, the Stratus DVs, and the Corima 40mm section...Those were good for around 66 seconds over the Ksyriums, if you ride em on a 40 k time trial at 20mph with a 20 degree head wind. The taller section ones were even more efficient if the wind was not a factor, but less advantageous in a side wind..still a significant advantage over the Ksyriums. One interesting figure was that about 15 degrees of "yaw" (angle off) a full disc wheel had NEGATIVE drag..A minus number of watts to move it through the air! Like a well trimmed sail, it actually provided some forward drive..
What caused all this study on my part was a couple of recent races I did at the Senior Games in Utah. We did a hillclimb into a very strong headwind and the next day we did a 40k time trial, again into about 30/40mph winds on the out leg..I finished a few minutes off the pace, using Ksyruims and clip ons on the Time trial..All the other guys were decked out with the best aero stuff and quite vocal that I was "giving them the race" by not using aero wheels, at least..Using the figures I found in my research against the results of the race, they were very right..the difference in our times was remarkably close to the figures I found..So, I now have some Aero wheels(ebay) and they ARE a LOT faster..I got a set of 303 Zipps for road racing and crits and some Corima (4 spoke rear, tall section 12 spoke front) for time trials.
The Zipps are much lighter than the Ksyriums, also..the Corimas less so, but still lighter..drawbacks? Expensive, Tubulars, not good to ride in the rain because you get grit on the brakes and wear the wheels..
So, there is what I found..I suggest some net-crawling for information..Every source says that carbon aero wheels are very much better than anything else available. One other thing I found..the new wheels are the biggest equipment performance gain I've had all season in my times over various known routes, much more of a gain than any new carbon bike frame..
Don Hanson aka Gnarly 928
PS. I have some Ksyriums SL SCCs that I love and use as training wheels. For an everyday performance wheel, they are hard to beat,. They are pretty harsh feeling.


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## Kerry Irons (Feb 25, 2002)

*Generally correct, but*



Gnarly 928 said:


> IIf I recall correctly, the Mavic Ks were significantly more efficient than a 32 spoke box rim, which they didn't even bother with in the tables, after they showed to be so much 'slower" than even the Ksyriums, which were very slow, indeed..compared to most of the "slick, Gucci, Unobtanium-priced" wheels. This was a racer mag. so they assumed that no one would ever race on regular wheels any more, hence they didn't test the box rims. I hear that Mavic no longer even makes the Open Pro rim..no demand in Europe.


Your time saving numbers are generally correct - the best aero wheels give you about 0.4 mph at 25 mph, which corresponds to 0.3 mph at 20 mph. That's a minute or so in a 25 mile/40 km time trial. That is compared to a "standard" 32 spoke wheel with a box section rim. Chet Kyle did a well-controlled study in 1997 quantifying these numbers, and the speed advantage of aero wheels has not changed in the interim. The fastest wheels then were the Hed TriSpoke (then it was the Specialized/DuPont), which is still on a par with the fastest wheels.

You are way off is in saying that "Mavic Ks were significantly more efficient than a 32 spoke box rim". In fact, the K is essentially the same as a standard wheel - your research showed that the advantage of aero wheels over the K was the same as the advantage over the standard wheel. Also, you are obviously not correct in saying that the MAVIC no longer makes the OP. This rim is widely available and considered the reference standard - if MAVIC has discontinued it, they have kept that very quiet. Even if MAVIC had discontinued this rim, they would have an equivalent unit in their lineup.


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## Gnarly 928 (Nov 19, 2005)

*A-ha! someone agrees...*



Kerry Irons said:


> Your time saving numbers are generally correct - the best aero wheels give you about 0.4 mph at 25 mph, which corresponds to 0.3 mph at 20 mph. That's a minute or so in a 25 mile/40 km time trial. That is compared to a "standard" 32 spoke wheel with a box section rim. Chet Kyle did a well-controlled study in 1997 quantifying these numbers, and the speed advantage of aero wheels has not changed in the interim. The fastest wheels then were the Hed TriSpoke (then it was the Specialized/DuPont), which is still on a par with the fastest wheels.
> 
> You are way off is in saying that "Mavic Ks were significantly more efficient than a 32 spoke box rim".
> 
> ...


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## AlexCad5 (Jan 2, 2005)

Kerry Irons said:


> You are way off is in saying that "Mavic Ks were significantly more efficient than a 32 spoke box rim". In fact, the K is essentially the same as a standard wheel - your research showed that the advantage of aero wheels over the K was the same as the advantage over the standard wheel. Also, you are obviously not correct in saying that the MAVIC no longer makes the OP. This rim is widely available and considered the reference standard - if MAVIC has discontinued it, they have kept that very quiet. Even if MAVIC had discontinued this rim, they would have an equivalent unit in their lineup.


 While k's have a reputation of being bullet proof, my favorite LBS has routinely complained of having to replace cracked rims. Now, I had NEVER heard of this from any other source, not on these boards, nor from any other rider. Then they showed me one that had just been returned. A nearly new k SSC wit a large crack running in the machined section between two spokes. 
So I said, "Oh, it's because they have lightened up these new rims by machining out that section, making it weaker."
And they said no. It happened on the older models too.
I have never considered them to be areo, not with that flat section facing the wind, but I had always considered them to be strong and stiff. I guess I'm left with stiff.

As far as Zipps and the various wheels that they offer, isn't it interesting that the wheels that CSC helped develop are not aero, nor are they carbon?

I've been riding AM Classics 420s for 2 full seasons and 350's for 1 season. I have decided that I like the short profile of the 350 in the front and the 420 with it's more aero profile in the rear. The 350 up front is much better for steerage in the inevitable crosswinds. I don't notice a problem with higher profile rims in the rear in terms of cross winds, probably because it is somewhat protected by my forward motion of my body/bike fram mass.


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## Under ACrookedSky (Nov 8, 2005)

So bringing this back to the OP, what is the advantage of a 30mm rim like the Ks or a Eurus versus a standard box one at reasonable speeds? The last few posts indicate that is neglible. They don't mention that a cyclist of average weight can easily use a 28 spoke OP for at least the front and often the rear, which would probably narrow any difference further. The Open Pro itself is not a true box rim like the GL 330, which has not been made for ten years. There are many other standard rims that do not have a flat backside but taper to a point, like Velocity Aeroheads, CXP 33, CXP 12 (if it is still being manufactured), et cetera.

It seems to me that 30 mm rims are really used in boutique wheel sets because they need a stronger rim to bridge the larger span between fewer spokes. The marketting men then decided they could turn this to an advantage by touting them as aero or semi-aero.


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## danl1 (Jul 23, 2005)

Here's a take on the topic from a voice I trust. Check about 2/3 of the way down the page, and again at the very bottom.

http://www.spectrum-cycles.com/64.htm

Answer? It depends. Out front, or in a TT? Sure they help, but how much depends on many variables, including wind direction and speed. Mixing it up in the peloton or on a crit circuit, doesn't matter a whit, and may be to one's detriment.


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## asgelle (Apr 21, 2003)

danl1 said:


> Here's a take on the topic from a voice I trust. Check about 2/3 of the way down the page, and again at the very bottom.
> 
> http://www.spectrum-cycles.com/64.htm
> 
> Answer? It depends. Out front, or in a TT? Sure they help, but how much depends on many variables, including wind direction and speed. Mixing it up in the peloton or on a crit circuit, doesn't matter a whit, and may be to one's detriment.


From the link.
"* Aerodynamics; this should be important to you if you race without a pack at times (time trial or off the front) or if you just want to look cool. Aero wheels are of essentially no additional value in a field. There the air is "dirty" and sitting in is no more difficult with box section rims. Of course more aerodynamic wheels offer no advantage during slower riding either. For example; during climbing, aero wheels give the rider no advantage. Strong cross winds will also eliminate any aerodynamic advantage you may get from deep section rims (with the exception of Shimano wheels). "


Tom may know alot about frames but about aerodynamics not so much. If you're using aero rims you should be racing. If you're racing the objective is to get to the line first which means being out front in the wind at some point. That point which separates first from second is the point of aero rims. Even in a pack, at moderate and higher speeds aero drag is the most significant cost in terms of power. Lowering C_d (which is all aero wheels do) is almost as effective in disturbed air as clean air. The statement regarding benefit at slow speeds is just plain wrong. The reduction in C_d gives an equal percentage drop in aero drag regardless of speed - drop C_d 5% aero drag drops 5% from 1 mph to 100 mph. It is true this benefit to the overall power requirement drops as speed drops, and may be small compared to the power to overcome gravity, but the benefit from reduced aero drag is always there. Finally, there is plenty of data available to show that drag reduction from aero wheels increases with yaw angle. That means aero wheels are more effective in a cross wind than a straight headwind. The only drawback is some people have trouble controlling their bike in a crosswind with deep profile rims, but that is another matter. In terms of drag, as long as you keep putting power to the pedals, aero rims are faster in a crosswind.


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## Nessism (Feb 6, 2004)

My understanding is that the flat blade spokes like used in the K's, or oval spokes like CX-rays, DO hold an aero advantage over round spoked wheels - rims being equal. Zip has some data to this effect posted on their website which is worth reading.


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## ttug (May 14, 2004)

*no sorry*



AlexCad5 said:


> While k's have a reputation of being bullet proof, my favorite LBS has routinely complained of having to replace cracked rims. Now, I had NEVER heard of this from any other source, not on these boards, nor from any other rider. Then they showed me one that had just been returned. A nearly new k SSC wit a large crack running in the machined section between two spokes.
> So I said, "Oh, it's because they have lightened up these new rims by machining out that section, making it weaker."
> And they said no. It happened on the older models too.
> I have never considered them to be areo, not with that flat section facing the wind, but I had always considered them to be strong and stiff. I guess I'm left with stiff.
> ...


You must not get out often

I have caused that wheel and others to fail. My weight was 195 and yes, the rim cracked. In fact, it untrued then cracked. That was a 2 pair extravaganza. 

Most of the wind tunnel models I have seen agree with what Kerry and others have pointed out and what John Cobbs published studies would also reflect. Aero wheel s are largely a function of the ride NOT rider type. A TT or for that matter off the front and solo rides of greater distances where you can get long straight distances. As to total aero bike and rider, thats another topic. A regular (round tubed bike, with aero wheels can be just as aero as some of the more zooty frames out there. See the total BS debacle of vertical flex and the bladed down tube. 

In the pack or in a cross wind, aero wheels are like testicles on a priest or big breasts on a nun: USELESS. 

I ride CXP-33's which are triple laced and I do so because they are truly sturdy. I do not give a toss as to their tested value


----------



## asgelle (Apr 21, 2003)

ttug said:


> In the pack or in a cross wind, aero wheels are like testicles on a priest or big breasts on a nun: USELESS.


Why USELESS in a crosswind? While it's true that drag goes up with yaw angle after abour 15 degrees, the drag on deeper rims remains lower than shallower ones at least to 30 degrees. Now if you're saying deep rims can't be controlled in a cross wind that's another matter and depends mainly on rider skill. I've never had trouble controlling deep rims in a crosswind and it's not uncommon to have reported wind speed over 30 mph.


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## ttug (May 14, 2004)

*because*



asgelle said:


> Why USELESS in a crosswind? While it's true that drag goes up with yaw angle after abour 15 degrees, the drag on deeper rims remains lower than shallower ones at least to 30 degrees. Now if you're saying deep rims can't be controlled in a cross wind that's another matter and depends mainly on rider skill. I've never had trouble controlling deep rims in a crosswind and it's not uncommon to have reported wind speed over 30 mph.



Any advantage that is conferred by "aero" rims would be negated by a significant cross wind. While there are models that would lessen this it is pretty much null and void at a specific point. It is however, way way below 30 mph. 

As to 30mph........When I weighed 255 and was riding my road bike I was picked up off the road and dumped in a ditch by 35mph winds that day. How did I know these were 35 mph winds? BECAUSE the weather instruments that were nearby and being used by the local lab said so. They were rather accurate for that day as it turned out. A hurricane was coming in and I was being stupid. 

While I am now 195, I KNOW that if anyone tells me sure, " I've never had trouble controlling deep rims in a crosswind and it's not uncommon to have reported wind speed over 30 mph" has to be completely full of steamy fecal matter. Thats a bald faced fabrication. A whopper. A fib. It is not so. 20 mph winds are almost my l;imit and yes, I have ridden in those. Once you pop above 25, then its sheer stupidity to be out and about.

I know you might not like the fact that I am calling you a bald faced liar for saying you sucked it up in 30+ mph winds, BUT the fact is that that much wind is not something to joke about.


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## danl1 (Jul 23, 2005)

_Tom may know alot about frames but about aerodynamics not so much_. 

Careful there. Glass houses and stones.

_If you're using aero rims you should be racing._

I like using them cause I like to go fast. I don't race, does that mean I have to sell them?  

_ If you're racing the objective is to get to the line first which means being out front in the wind at some point. _ 

And if you're going to be first at the line, the time you spend out front better be a slim percentage.

_That point which separates first from second is the point of aero rims. _ 

Actually, the point that separates first from second is better performance. Aerodynamics is but one smallish factor among many. Lance and that crowd could kick my butt, and I expect yours, riding a Huffy with flat tires. If an aero advantage costs more in other ways than it gains in aero, it's silver medal time.

_Even in a pack, at moderate and higher speeds aero drag is the most significant cost in terms of power. _ 

True statement. Also irrelevant to the discussion at hand, since the aero drag of the wheels is only a fraction of the total. Worry about the second decimal point after you've got the first worked out.

_Lowering C_d (which is all aero wheels do) is almost as effective in disturbed air as clean air. _ 

True for scaled objects and decent Reynolds numbers. At the scale and speed of rims and hubs, the size of the eddys of dirty air effectively mean that airflow comes from the sides as often as the front. At these scales in dirty air, cylinders are usually more efficient than foil sections. Plus, aero rims add rotating weight, the inertia of which will kill you in a jump. 

_The statement regarding benefit at slow speeds is just plain wrong. The reduction in C_d gives an equal percentage drop in aero drag regardless of speed - drop C_d 5% aero drag drops 5% from 1 mph to 100 mph. _ 

This is the incorrect statement. It's a coefficient, not a linear constant. Drag increases as an exponent of speed. 

_Finally, there is plenty of data available to show that drag reduction from aero wheels increases with yaw angle. That means aero wheels are more effective in a cross wind than a straight headwind. [....]In terms of drag, as long as you keep putting power to the pedals, aero rims are faster in a crosswind._

Increases with yaw angle...up to a point. A "strong" crosswind that was discussed effectively moves the yaw angle past the stall angle of the aero features in question. At that point, cylindrical or even square objects are more efficient within constrained sizes. Further, at the narrow angles where they are more efficient than head-on, they create lift, representing a sideways vector that must be counteracted if the rider is to maintain their line. That steering force against the ground is.....friction, and it's often more than equal to the aero gain by the yaw angle, especially since that effects more than just the wheel, but the whole body.

Empirically, means are defined by ends. If your assertions were valid, the peloton would be filled with disc wheels and deep-section aeros, and there would not be a box-section rim in sight. These guys go with what works, and the sponsor's added decal space would be gravy. To suggest that they willingly give up both performance and cash because they know less than you about aerodynamics is folly.


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## ttug (May 14, 2004)

*I agree, BUT*



danl1 said:


> _Tom may know alot about frames but about aerodynamics not so much_.
> 
> Careful there. Glass houses and stones.
> 
> ...


Why let facts get ibn the way of letting somebody tell you how they can control their bike in 30 mph winds. COME ON MAN, this is BEER TALK....


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## wipeout (Jun 6, 2005)

ttug said:


> Why let facts get ibn the way of letting somebody tell you how they can control their bike in 30 mph winds. COME ON MAN, this is BEER TALK....


Why is controlling ones bike in 30 MPH winds so unbelievable? Check out the 2004 Furnace Creek 508 where they had 50 MPH winds to contend with...


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## Koop (Oct 23, 2005)

Nessism said:


> My understanding is that the flat blade spokes, like used in the K's, DOES hold an aero advantage over round spokes. Oval spokes, like CX-rays have a similar aero advantage to that of blade spokes. Bottom line is that Ksyrium wheels do hold some aero advantage over round spoke conventional wheels but not over a conventional wheel with skinny oval spokes.


There was apparently some adavantge to Ksyrium's at least in the 2000TDF as Lance and the US Postal team rode them despite contractual obligations with Bontrager (per Cycle Sport America Oct 2005)


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## Under ACrookedSky (Nov 8, 2005)

ttug said:


> I KNOW that if anyone tells me sure, " I've never had trouble controlling deep rims in a crosswind and it's not uncommon to have reported wind speed over 30 mph" has to be completely full of steamy fecal matter. Thats a bald faced fabrication. A whopper. A fib. It is not so. 20 mph winds are almost my l;imit and yes, I have ridden in those. Once you pop above 25, then its sheer stupidity to be out and about.


That's funny. I had the same thoughts about that statement--well, maybe not so colorful. Anyone who says their deep rims are not a problem in strong wind because of their godlike bike handling skills is full of sh!t.


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## Under ACrookedSky (Nov 8, 2005)

wipeout said:


> Why is controlling ones bike in 30 MPH winds so unbelievable? Check out the 2004 Furnace Creek 508 where they had 50 MPH winds to contend with...


How many were riding Zipp 404s, or equivalent, and said, "they never had a problem?"

Each Spring I usually get several rides in with 30+ wind. My usual technique is to put the bike in its lowest gear and grind it back home, sometimes standing to make forward progress. You live in constant fear you'll get blown off the tarmac or into the path of an approaching auto, so you keep your bars in a death grip. It's a bloody adventure, and at 70-75 kilos I'm not all that big. During April it is Open Pro rims for me; those are still a handfull in any real wind.

This year I did a charity ride with about fifteen minutes of forty-five mph gusts at the end. Most people just stopped and stood by the side of the road.


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## Gnarly 928 (Nov 19, 2005)

*30mph wind? so?*



Under ACrookedSky said:


> That's funny. I had the same thoughts about that statement--well, maybe not so colorful. Anyone who says their deep rims are not a problem in strong wind because of their godlike bike handling skills is full of sh!t.


I happen to live and ride an area where winds of 30mph are called 'light'. The Columbia River Gorge, windsurfing capitol of the US. I probably would not ride a disc wheel across the wind direction, if given a choice. But you can handle a bike in 30+ mph winds..lots of riders from here do so daily without problems.
Here is another variable to toss into this interesting discussion.."Apparent Wind" A very important phenominum..A large factor in the aerodynamics of bikes and other wind related sports. Windsurfing, for example. When you are going 30 mph with a true wind direction and speed of 30 mph from your "3 o-clock"..what you actually encounter is something closer to a 45 degree apparent wind at a bit above 30mph. I don't want to do the math.. but you get the idea..


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## ttug (May 14, 2004)

*yes, I see*



Gnarly 928 said:


> I happen to live and ride an area where winds of 30mph are called 'light'. The Columbia River Gorge, windsurfing capitol of the US. I probably would not ride a disc wheel across the wind direction, if given a choice. But you can handle a bike in 30+ mph winds..lots of riders from here do so daily without problems.
> Here is another variable to toss into this interesting discussion.."Apparent Wind" A very important phenominum..A large factor in the aerodynamics of bikes and other wind related sports. Windsurfing, for example. When you are going 30 mph with a true wind direction and speed of 30 mph from your "3 o-clock"..what you actually encounter is something closer to a 45 degree apparent wind at a bit above 30mph. I don't want to do the math.. but you get the idea..



Yes I do get that. The poiint was that what would happen to the "aero" advantage. At a point, the cross wind becomes: LIFT. You wid surf, then you know a lot more about LIFT and wind than your average person.

As was also stated, yup, there are designs in aero wheels where it would NOT be a good idea. Disks are one, another were HED 3's. However, IMO, 30mph is not fun and I think very very few would disagree that hey these aero wheels gave an advantage that day. If so, then great, go buy a pair.


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## ttug (May 14, 2004)

*[email protected][email protected][email protected]*



wipeout said:


> Why is controlling ones bike in 30 MPH winds so unbelievable? Check out the 2004 Furnace Creek 508 where they had 50 MPH winds to contend with...



Those were GUSTS of up to 50 mph. Do you have any idea what a sustained 50 mph wind can do to a cyclist? Check out some of the Kona Iron Man competitions.People do not normally travel at RIGHT ANGLES on a bike right?

The wind speeds are believable, the actions stated by some are not.


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## Gnarly 928 (Nov 19, 2005)

*Back to the questions in the OP*



Under ACrookedSky said:


> So bringing this back to the OP, what is the advantage of a 30mm rim like the Ks or a Eurus versus a standard box one at reasonable speeds? The last few posts indicate that is neglible. They don't mention that a cyclist of average weight can easily use a 28 spoke OP for at least the front and often the rear, which would probably narrow any difference further. The Open Pro itself is not a true box rim like the GL 330, which has not been made for ten years. There are many other standard rims that do not have a flat backside but taper to a point, like Velocity Aeroheads, CXP 33, CXP 12 (if it is still being manufactured), et cetera.
> 
> It seems to me that 30 mm rims are really used in boutique wheel sets because they need a stronger rim to bridge the larger span between fewer spokes. The marketting men then decided they could turn this to an advantage by touting them as aero or semi-aero.


One of the drawbacks of the internet and forums like this is that people get caught up in arguments and go all huffy. Another is that you can say stuff, whatever you've come to believe, and it sounds kinda true..so others may take it as fact. Now in this thread, some are saying Aero wheels are a bunch of crap, hype, marketing scam, etc. They say stuff like "in a race, if you are strong and smart, you'll not do any better with aero wheels"."Aero wheels in a pack are useless" "in a cross wind, aero wheels lose their advantage totally" "Aero wheels are a distraction, just train, don't waste your time with Aero wheels"...and some of that sounds sorta "right" doesn't it? We'd all like to believe stuff like that. But without any evidence, what "makes sense if you are a *real racer*" and not some dorky equipment geek is just.."internet opinion", unsupported by facts.. Reading the posts over caused me to go back and look at some of the published testing results again, just to do a reality check. I'll stick a couple here for anyone interested in actual test data rather than someone's "take" on what they "know" from "years as a ____ racer". I've not taken the time to organize any of these sources, and if you have more interest, you'll find tons of actual data on the net (as well as many self-designated experts who will 'scoff' at the numbers without offering any real data of their own) Here's just a few sites I found in 10 mins of Google to get you going.(if actual data interests you.) The last site is not testing, but unsubstantiated theory.
www.bsn.com/cycling/wheelaerodynamics.html
http://damonrinard.com/aero/
www.carbonsports.com/aerodynamik_aufrad.lasso
Hopefully I transcribed the 'addies' properly. The third one has a good explaination (or theory, if you prefer) of how aero wheels actually work better in a pack. Breifly,a synopsis, for those of you who won't bother with the links. Also, the Carbonsports site explains why a tall section rim tests out better..
As a bike wheel moves down the road, the top circumference of the wheel is moving through the air at twice the speed of the bike it is attached to while the bottom of the wheel is not moving through the air at all. Think about that for a second..Ok? The center of the wheel is moving through the air at the same speed as the bike.. Ok, now we jump onto "the train" and tuck into the best sweet spot in the pack...all day, we can get sucked along at a high rate of speed, but we feel little wind because the pack creates a moving pocket of air, dragging it along, us included. But, at say 35 mph, the outer circumference of your wheel, at the top, is cutting through the air at 70 mph! At least every time you get a bit out of sync with the draft it is. Even in a perfect world if you had 100% of the draft, and no air got past the riders in front ot you, your upper circumference/rim and tire would still be moving at 35mph through that air.. Where the big gain is made using a tall rim section (according to the scientists who've done all the math) is in reducing the spoke length..As you move away from the hub towards the rim and tire, the peices of the wheel have to move faster through the air as they rotate. Spokes have lots of drag.(see the other test articles) If you shorten the spokes and replace that length of spoke with a smooth rim, you reduce the drag..A lucky side effect is that as you increase rim section height you also increase the rims strength and you can then use fewer spokes as well as shorter spokes..it all works to reduce aero drag significantly, again, according to the scientists and the testing they've done..And if you look in a pro peloton, you will see that THOSE guys seem to believe the scientists, judging from how many are riding aero stuff..
well, the snow is gone off the road here this morning, 
finally, so bye bye..
Don Hanson


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## flying (Feb 17, 2004)

Gnarly 928 said:


> . Where the big gain is made using a tall rim section (according to the scientists who've done all the math) is in reducing the spoke length..As you move away from the hub towards the rim and tire, the peices of the wheel have to move faster through the air as they rotate. Spokes have lots of drag.(see the other test articles) If you shorten the spokes and replace that length of spoke with a smooth rim, you reduce the drag..A lucky side effect is that as you increase rim section height you also increase the rims strength and you can then use fewer spokes as well as shorter spokes.


You know that sounds so logical. It makes sense


----------



## ttug (May 14, 2004)

*I have to buy it now*



Gnarly 928 said:


> One of the drawbacks of the internet and forums like this is that people get caught up in arguments and go all huffy. Another is that you can say stuff, whatever you've come to believe, and it sounds kinda true..so others may take it as fact. Now in this thread, some are saying Aero wheels are a bunch of crap, hype, marketing scam, etc. They say stuff like "in a race, if you are strong and smart, you'll not do any better with aero wheels"."Aero wheels in a pack are useless" "in a cross wind, aero wheels lose their advantage totally" "Aero wheels are a distraction, just train, don't waste your time with Aero wheels"...and some of that sounds sorta "right" doesn't it? We'd all like to believe stuff like that. But without any evidence, what "makes sense if you are a *real racer*" and not some dorky equipment geek is just.."internet opinion", unsupported by facts.. Reading the posts over caused me to go back and look at some of the published testing results again, just to do a reality check. I'll stick a couple here for anyone interested in actual test data rather than someone's "take" on what they "know" from "years as a ____ racer". I've not taken the time to organize any of these sources, and if you have more interest, you'll find tons of actual data on the net (as well as many self-designated experts who will 'scoff' at the numbers without offering any real data of their own) Here's just a few sites I found in 10 mins of Google to get you going.(if actual data interests you.) The last site is not testing, but unsubstantiated theory.
> www.bsn.com/cycling/wheelaerodynamics.html
> http://damonrinard.com/aero/
> www.carbonsports.com/aerodynamik_aufrad.lasso
> ...


How could I have been so mistaken? I just know that none of those folks SELL things. A truly NON BIASED source.

Every source has an axe to grind, but sorry, the science is very real. Unless you happen to not believe in flight, or the existence of heavier than air object calles aircraft, I do not think there is really any need to really go on is there?

I m certain that there are gobs and gobs of folks who can put out the watts needed to go 35 mph. Yes, there are hordes of them. AND LOOK! They are going to the store to buy tht poduct that is premised on totally unreal data. Its not FRAUD, better yet, ITS STUPIDITY!!!!


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## Gnarly 928 (Nov 19, 2005)

flying said:


> You know that sounds so logical. It makes sense


You funny guy!
Don Hanson


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## Under ACrookedSky (Nov 8, 2005)

*So what are the numbers?*

Given the original post, it is nice to get side tracked by the benefits of 50 mm deep rims at 30+ mph, but that's pretty much irrelevant. If I spit before climbing, I wil climb faster. The science is irrefutable. The increase will be so small that it would be rediculous to tell people to hawk a good lugie before starting a climb.

Back to the original question. The prebuilt wheels the original post mentions usually come with a 30 mm deep rim. The gold standard for the hand built wheels should be compared with is a wheel built with an Open Pro rim. By eyeballing an Open Pro, I would guess that rim is 17 - 19 mm.

So, at reasonable speeds for the typical cyclist that buys these "semi-aero" pre built wheels, what is the speed gain over a set of Open Pros? Is it large enough to say that the marketting claims are more than hype?


----------



## ttug (May 14, 2004)

*ooops*



Under ACrookedSky said:


> Given the original post, it is nice to get side tracked by the benefits of 50 mm deep rims at 30+ mph, but that's pretty much irrelevant. If I spit before climbing, I wil climb faster. The science is irrefutable. The increase will be so small that it would be rediculous to tell people to hawk a good lugie before starting a climb.
> 
> Back to the original question. The prebuilt wheels the original post mentions usually come with a 30 mm deep rim. The gold standard for the hand built wheels should be compared with is a wheel built with an Open Pro rim. By eyeballing an Open Pro, I would guess that rim is 17 - 19 mm.
> 
> So, at reasonable speeds for the typical cyclist that buys these "semi-aero" pre built wheels, what is the speed gain over a set of Open Pros? Is it large enough to say that the marketting claims are more than hype?


I defy you to get more than 1 marketing rep agree on what a typical rider would mean in this context.

Cynical? Sardonic? YES, OH YES


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## Under ACrookedSky (Nov 8, 2005)

ttug said:


> I defy you to get more than 1 marketing rep agree on what a typical rider would mean in this context.
> 
> Cynical? Sardonic? YES, OH YES


Yes, it seems as though manufacturers target riders who tool around on a Sunday ride at 30 mph, solo, and often in winds of equal speed.


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## otoman (Mar 8, 2004)

AlexCad5 said:


> As far as Zipps and the various wheels that they offer, isn't it interesting that the wheels that CSC helped develop are not aero, nor are they carbon?


Those are just DT Swiss RR1.1 rims with a standard Zipp hub. CSC had about as much to do with that product development as the pitcher whose name was stamped into your childhood baseball glove. They might have picked out which product to which their name was affixed, but that's about it.


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## den bakker (Nov 13, 2004)

otoman said:


> Those are just DT Swiss RR1.1 rims with a standard Zipp hub. CSC had about as much to do with that product development as the pitcher whose name was stamped into your childhood baseball glove. They might have picked out which product to which their name was affixed, but that's about it.


The press release from zipp made it sound like they had just invented the successor to the space shuttle. Interaction with the team, redisigning etc etc. 
Then you look at the picture of the wheel and you realize just how full of bull they are. 

For those that can take it: 
http://www.zipp.com/products/wheels/csc_team.shtml


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## Max-Q (Feb 6, 2004)

For me, I purchased my Ksyrium SLs because they looked cool and they were lighter than the wheels I was using at the time. After 3 years of riding on them I can say that they are nice wheels but they are not:

1) Aero - I have Zipp 404s and Lightweights which are aero. K's simply are not. They use a box type rim and big bladed spokes that catch sidewinds in a bad way. 

2) Bulletproof - Mine are destroyed. I never hit any holes and I never crashed with them, they simply ripped 4 spokes through the rim. 

3) Light - At 1500+ grams they are a decent weight but nothing spectacular. 

In my opinion they are nothing great in regards to performance or reliability, just a pretty face on an average body.


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## asgelle (Apr 21, 2003)

ttug said:


> I know you might not like the fact that I am calling you a bald faced liar for saying you sucked it up in 30+ mph winds, BUT the fact is that that much wind is not something to joke about.


Well, the weather site I use doesn't go back to last spring but it does go back to last weekend. From the report,
http://www.weather.com/weather/pastweather/hourly/USNM0004?when=112705&stn=0
you can see we had wind over 30 mph for an hour and another hour at 25. I can send you the names of several people I was riding with then. I can also send you names of people who will tell you it was less windy than last years Hillsboro Road Race and that I and at least two others, who I can name, raced on Zipp 404's. So call me a liar if you want but I have data to prove what I say.


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## al0 (Jan 24, 2003)

Gnarly 928 said:


> The best(most comprehensive) write up I found was from a Euro magazine, I wish I could cite a name but I've forgotten what it was or where I found it, exactly. It agreed with what all the other studies and aero/wind tunnel testing says, but this study had no 'vested interest' that I could discern./QUOTE]
> 
> The magayine was German "Tour". I have posted many of those results in this forum.
> 
> ...


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## Gnarly 928 (Nov 19, 2005)

*Wow. I guess I must be special*



al0 said:


> Gnarly 928 said:
> 
> 
> > The best(most comprehensive) write up I found was from a Euro magazine, I wish I could cite a name but I've forgotten what it was or where I found it, exactly. It agreed with what all the other studies and aero/wind tunnel testing says, but this study had no 'vested interest' that I could discern./QUOTE]
> ...


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## ttug (May 14, 2004)

*yes*



Under ACrookedSky said:


> Yes, it seems as though manufacturers target riders who tool around on a Sunday ride at 30 mph, solo, and often in winds of equal speed.



How did you know that????


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## ttug (May 14, 2004)

*sure*



Gnarly 928 said:


> Hi, that was the mag. that said Open Pros aren't being made and that seemed to be the least biased towards one brand in their aero wheel test results. Tour..
> Dang, my 'best" training wheels are Nimble Spiders. But I see you say they are the worst "aero" rim. I'd call em climbing rims because they are pretty light (that is why I got some) but really quite low, somewhere around 22mm high? Here in my riding area, climbing and descending is the rule, so I train on clinchers for all the downhill work. Lots of wet gritty road surfaces, too..not the best on full carbon rims..
> I guess everyone that thinks 30 miles per hour is some kinda warp speed. Some must think I am special (I don't) but we spend a lot of time at speeds like that here in my home area. Long hills, huge tailwinds, big headwinds, short steep climbs. So I see sustained 35 mph sections of almost every solo ride. Not because I am a 'cycling god', but because the terrain lets me go that fast...that and my aero wheels...You nay sayers, keep the old boxy spokey wheels if you think you are beyond the law (of physics) You can give away all the time you want. Me, I'll take the .4% advantage (small, yes, but every little bit helps) that riding some Zipps or Lews or Corimas will give me and enjoy.
> Don Hanson


Where on this planet do you live that sustains an environment of perpetual 35 mph winds? 

Yes, there are climates that nearly match that. Usually at the top of uninhabitable peaks that support twisted foliage and certain species of lichen . Odds are, not a bunch of group rides go on there. Just a hunch.

However, on top of biking in nearly uninhabitble places, there are cycling and sports magazines that offer totally non biased articles; the existence of which are based on the revenues of SPONSORS and or advertisements in which, (here comes another hunch) people try to sell things.

I am relieved hiowever to know that 30 mph solo is not a biggy. Hey, just becuase there are eleite cyclists who could not touch that; does NOT mean that it is not doable.......Certainly. Hey, I gotta go now, the Beatles just got back together and they are playing in my basement right now......


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## ttug (May 14, 2004)

*windy huh?*

So, there I was, saying gosh, 35 mph is alot of wind. AND GUESS WHAT?

I Googled it and looky looky. A little research at Weather.com and USA Today yielded the most INTERESTING RESULTS:

"With an average annual wind speed of 35.3 mph, Mount Washington's winds are the highest. But many people don't think it should be considered in the same way as St. Paul Island, Alaska, with its annual average speed of 17.6 mph, because the only people who live on Mount Washington's summit are those at the Weather Station. The Observatory's Web site http://www.mountwashington.org/ has more on what's on top of the mountain. 

If you're interested in the USA's highest wind speeds, look at the USATODAY.com Answers archive: Windy cities where, among other things, you'll see that Chicago isn't particularly windy, especially when compared with some places in Alaska." 

SO, 35 mph winds would make your location one of the windiest on the North American continent. In fact, at the top of MOUNT WASHINGTON its 35.3 mph. Hey, you know the trees there almost grow horizontally due to the constant winds? In fact, it has been deemed to be one of the LEAST HABITABLE places in NORTH AMERICA.

I would BET BEER that anybody who once again says, sure, 30 mph is no problem for me and my bike handling skills is a LIAR.


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## flying (Feb 17, 2004)

ttug said:


> I would BET BEER that anybody who once again says, sure, 30 mph is no problem for me and my bike handling skills is a LIAR.


I bet a lot of folks confuse 30mph gusts with 30mph winds 

We do get a lot of winds that speed here but not sustained.
I tell you what though even gusts of that speed picks up small stones & they feel like bullets


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## ttug (May 14, 2004)

*sure*



asgelle said:


> Well, the weather site I use doesn't go back to last spring but it does go back to last weekend. From the report,
> http://www.weather.com/weather/pastweather/hourly/USNM0004?when=112705&stn=0
> you can see we had wind over 30 mph for an hour and another hour at 25. I can send you the names of several people I was riding with then. I can also send you names of people who will tell you it was less windy than last years Hillsboro Road Race and that I and at least two others, who I can name, raced on Zipp 404's. So call me a liar if you want but I have data to prove what I say.



You are correct. The data you provide proves you are a liar. Congratulations you must be so proud.


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## ttug (May 14, 2004)

*yes, yes they do*



flying said:


> I bet a lot of folks confuse 30mph gusts with 30mph winds
> 
> We do get a lot of winds that speed here but not sustained.
> I tell you what though even gusts of that speed picks up small stones & they feel like bullets



I just didnt have the heart to post the highest recorded winds of 200 mph in Antarctica. These were not storm winds. I wonder how my bike would handle in 200 mph wind huh? Yeah, I guess I would have to gear it low and just hunker down as my bike and body were driven into an 8 foot thick wall of ice at 200 mph. No worries, my aero wheels would save the day!


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## fmw (Sep 28, 2005)

I rather like Don's post. I have no reason to dispute the data. I will mention, however, that there is a lot of "scientific data" on some sites that isn't much better than an opinion. Often, opinions or marketing are wrapped up in numbers for the sake of credibility. I'm not saying this is the case with these sources on aero wheel design, I'm just suggesting that the net can be a dangerous place to get "proof" of anything. I have an area of expertise (not in cycling) and I can tell you there is some very believable, well presented nonsense on the internet.

After reading the thread, my guess is that aero wheels most likely do provide a measurable improvement in performance but such a minor one that all but the world class racers fail to experience the difference. I happen to prefer my non-aero, mulit spoked wheels simply because they are more comfortable to ride. I'm a geezer and not a world class racer. What is best for Lance Armstrong is probably not best for me. 

Sometimes, measurable reality can differ from practical reality. In other words, I suspect everyone that has posted here is correct from their own perspective.


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## Franchise (Mar 9, 2002)

*Something to share*

I don't know if new wheels are more aero, but I wanted to share something with this forum. I was out on a ride to enjoy some crisp winter air, when I saw a bike with Lightweight Wheels(the all carbon fiber, $3K set) on a Richard Sachs frameset. I immediately stopped to see if I could get a closer look.

The owner of the bike, was a pretty overweight, and a stockbroker. He told me that he had been cycling since college, and that he had tried all of the high end bikes - Pinarello's, Colnago's, etc. He said that his combo was the best for him. He loves his bikes, and he loves his wheels. He continued to tell me that it was more cost effective for him to buy a set of wheels that don't need to be trued/serviced, and are essentially bulletproof. He also told me that he was faster on this set of wheels than anything else due to their aerodynamic ability.

While I consider deep dish rims to be more aerodynamic intuitively, I cannot really quantify that with any information. Also, I think that people have found few things to upgrade on their bikes, and wheels just seem to be something to find a fault in, in order to make another purchase.

I considered the man I met in the park to really love his bikes and cycling. While he may not be a pro, I'm sure that in his eyes, his wheels/bike is well worth it. In the end, I think that this is the most important aspect of it. So, I will not be one to criticize him for using wheels that are definitely pro cycling equipment. When you think about it, don't we all pretty much ride equipment that we shouldn't? I wish everyone well, no matter the equipment.


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## asgelle (Apr 21, 2003)

ttug said:


> You are correct. The data you provide proves you are a liar. Congratulations you must be so proud.


You sound like the husband found in bed with another woman by his wife who the denies there's a woman there and says who are you going to believe me or your lying eyes. I have no idea what you're talking about here, but the weather data is clear that on a random weekend we had winds over 30 mph and I can give you the names of people I was riding with. it must be hard when there are objective facts to stand in the way of you blindly refuting what people write.


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## Gnarly 928 (Nov 19, 2005)

ttug said:


> Where on this planet do you live that sustains an environment of perpetual 35 mph winds?
> 
> Yes, there are climates that nearly match that. Usually at the top of uninhabitable peaks that support twisted foliage and certain species of lichen . Odds are, not a bunch of group rides go on there. Just a hunch.
> 
> ...


 Hey fellow, thanks for all the sarcastic, childish, non-constructive dialogue.(Not!) Got any facts, or do you just get off on making fun of everyone, trying to ridicule everything, saying "IS NOT!" over and over, louder and louder?
If you can show us a study of where aero wheels are always, or even sometimes slower than regular wheels, why don't you do that rather than taking cheap(and personal) potshots at anyone who posts otherwise? 
If you, personally, think a rider has to be Pro-caliber to get any benefit from pro-caliber gear, that is your opinion, others have different opinions. Me, I don't ride a second hand Schwinn, just because I am "only" a masters racer, and someone says that me riding a nice bike is stupid. I also don't appreciate being made fun of by some stranger on the net. Why resort to personal attacks to try to "make your point"? 
If someone wants to run Open Pro rims (or whatever) that is their choice. If someone wants to run carbon aero rims, that's their choice. As I pointed out to draw all these flames and derogitory, sarcastic comments, many different studies show the carbon aero rims ARE more efficient in most conditons. No studies show the standard rims with any advantage whatsoever, other than price and durability, perhaps. So I chose to upgrade to the most efficient available wheels..Does that make me "lame?" Perhaps I am also lame because I ride a carbon bike rather than a used beach cruiser.. Why dissrespect someone who choses to read up on equipment and then switch to the best gear he/she can afford? Make you feel big? Why imply someone someone is lying, that he/or she "can't" really hit 30mph or "doesn't really " live where it's windy and hilly? Why say "you don't need that" or "that data is wrong" without any constructive advice or proof? Why not give some real positive comments rather than 'sniping away' at whatever anyone else says, and when that doesn't work, sniping away at the person himself?
Sorry, Forum, I should not respond to this kinda "net-baiting" but sometimes it gets to me.
Don Hanson


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## rocco (Apr 30, 2005)

This thread is an exemplary waste of time.


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## ttug (May 14, 2004)

*whoah*



Gnarly 928 said:


> Hey fellow, thanks for all the sarcastic, childish, non-constructive dialogue.(Not!) Got any facts, or do you just get off on making fun of everyone, trying to ridicule everything, saying "IS NOT!" over and over, louder and louder?
> If you can show us a study of where aero wheels are always, or even sometimes slower than regular wheels, why don't you do that rather than taking cheap(and personal) potshots at anyone who posts otherwise?
> If you, personally, think a rider has to be Pro-caliber to get any benefit from pro-caliber gear, that is your opinion, others have different opinions. Me, I don't ride a second hand Schwinn, just because I am "only" a masters racer, and someone says that me riding a nice bike is stupid. I also don't appreciate being made fun of by some stranger on the net. Why resort to personal attacks to try to "make your point"?
> If someone wants to run Open Pro rims (or whatever) that is their choice. If someone wants to run carbon aero rims, that's their choice. As I pointed out to draw all these flames and derogitory, sarcastic comments, many different studies show the carbon aero rims ARE more efficient in most conditons. No studies show the standard rims with any advantage whatsoever, other than price and durability, perhaps. So I chose to upgrade to the most efficient available wheels..Does that make me "lame?" Perhaps I am also lame because I ride a carbon bike rather than a used beach cruiser.. Why dissrespect someone who choses to read up on equipment and then switch to the best gear he/she can afford? Make you feel big? Why imply someone someone is lying, that he/or she "can't" really hit 30mph or "doesn't really " live where it's windy and hilly? Why say "you don't need that" or "that data is wrong" without any constructive advice or proof? Why not give some real positive comments rather than 'sniping away' at whatever anyone else says, and when that doesn't work, sniping away at the person himself?
> ...


Don, my entire goal in any of these posts has not been to say, yeah, look at the lamers who buy this etc etc. Rather, look at the lamers who make claims to sell the product. Ride what you will. Go nuts. A fellow rider I see has a Wilier frame, carbon everything and MAYBE, MAYBE gets 50 miles a week in. I think the bike is a piece of art. It is wonderful. However, thats about where my observation ends. I continue my ride and life goes on.

However, when there are assertions made that are at best, well, lets just say highly improbable, you have made a valid point, I did indeed observe that it just might not work the way alot of folks who sell the stuff claim.

Ride well, be safe and again, its not the messenger here, sorry.


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## MShaw (Jun 7, 2003)

rocco said:


> This thread is an exemplary waste of time.


Most (all?) religious arguments are!

M


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## divve (May 3, 2002)

rocco said:


> This thread is an exemplary waste of time.


You are a waste of time.


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## rocco (Apr 30, 2005)

Alah akbar and my dad is stronger than your dad.


P.S. I think it's about time for a RBR member bike race.


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## cwg_at_opc (Oct 20, 2005)

*RBR bike race: as long as...*

there's a 30mph cross-wind at 15 degrees and i can watch from my car ;-)

i've been reading this thread since it's started and have been carefully avoiding
getting into the discussion.

25yrs ago i'd ridden in what was probably a sustained 20mph head/tail wind(Ocean
Pky, Jones Beach, Long Island, NY) and it was <b><i>not</b></i> fun. it was during a large,
organized, family-ride(you and 5000+ of your closest friends, not) for an out-and-back
50mile ride. at least the tail wind was OK, but squirrelly. it was not something i
added to my, 'let's do that again" list. anyway, this was right when clip-on aerobars
were known but hard-to-find, and expensive. i had seen them in the coverage of
RAAM, and during the return leg into the head-wind, to get into the flat-back aero
position, i leaned forward with one arm on the drop, while steadying with the other
hand. i barely made it to the finish.

as for the actual benefits of aero wheels, you can definately feel the forward
acceleration when the wind is just right. that negative lift thing really does happen.
i'd venture to say that one would be better served by training harder and smarter first,
and choosing your equipment wisely when it's called for. as someone has linked to
elsewhere in this thread, the Zipp website is full of very interesting information about
aerodynamics and wheel design.



rocco said:


> P.S. I think it's about time for a RBR member bike race.


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## rocco (Apr 30, 2005)

cwg_at_opc said:


> there's a 30mph cross-wind at 15 degrees and i can watch from my car ;-)
> 
> i've been reading this thread since it's started and have been carefully avoiding
> getting into the discussion.
> ...



When I lived in Chicago I did a lot of my after work/evening training rides along the lakefront bike path down to Southshore and back. In the spring sustained and gusting north winds at 15 to 25mph that roar unobstructed off of Lake Michigan are almost the norm. Chicago is as flat as it gets but those winds are like mountains.


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## patchito (Jun 30, 2005)

Another reality check: You're actually arguing (not very persuasively I'm afraid) over ego driven minutiae so tangential to the original topic it almost seems like a thread hijack. I've yet to read a post of yours where you _don't_ come across as a pompous ass.


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