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Wheels: Looks or Performance?(19 posts)

Wheels: Looks or Performance?PsyDoc
Oct 16, 2002 10:51 AM
This message was posted over on Cycling Forum. Hakan obviously put A LOT of time into this post.

Date: October 15, 2002 03:14 PM
Author: Håkan (Hakan.Carlson@home.se)
Subject: Looks or performance?

(Most of this have been published here a couple of weeks ago, but the search function don't seem to find it)

The most important performance factors of a wheel is aerodynamics, weight and last and least inertia. Aerodynamics is by far the most important factor, at least as long as the speed is higher then 20-25km/h. That the parameters above actually are listed in order of importance can be read about here: http://www.bike.com/template.asp?date=8%2F1%2F2001&lsectionnumber=6

Quote:
"So, what do all these numbers mean? It means that when evaluating wheel performance, wheel aerodynamics are the most important, distantly followed by wheel mass. Wheel inertia effects in all cases are so small that they are arguably insignificant."
Or you can find out by yourself by testing different (REALISTIC!) values for the different parameters here: http://www.analyticcycling.com

The German magazine Tour(http://www.tour-magazin.de) have tested several different wheels in issue 7/2002.

Measured weighs for Ksyrium SSC SL:
Front 730g Rear 884g (excl Q/R)

Standard wheel with OpenPro-rim and 32-spokes:
Front 676g Rear 781g (excl Q/R)

The standard wheels are built with Sapim (http://www.sapim.be) aero spokes and hubs from the German manufacturer Tune:
http://www.tune.de

Tour also tested the aerodynamics of the wheels in Mavics windtunnel. The wheels have almost the same aerodynamics:
Ksyrium SL: 251g, OpenPro: 258g ie less then 3% difference.

The test also shows that the inertia is almost the same for the wheels:
Ksyrium SL: 121Joule(J), OpenPro: 116J, a difference of 4%.

But what about the 'old' Ksyriums?
What about the aerodynamics, weight and inertia of them?

Tour have in earlier issues teste them too, unfortunately not in the windtunnel. Aerodynamics for a bicycle wheel is largely set by the rims surface area or rims with a higher profile are faster. Read more here:
http://www.bicyclesports.com/technical/aerodynamics/watts_drag.html

The rim profile of the Ksyriums are not very good, compare with the CXP33-rim:
http://www.mavic.com/servlet/srt/mavic/road-prod_fiche?produitsid=46&lg=uk

The spokes of the Ksyriums are very different but they are so fat(1,7 x 5,2 mm) that if they make a difference they make the aerodynamics worse. Thin aero spokes like the Sapim CX Ray are 0,95 x 2,3 mm. Wheels built with CXP33-rims and thin aerospokes will in practice have the same aerodynamics as the 'old' Ksyriums.

But what about weight and inertia for the wheels? Mavic is selling the Ksyriums as lightweight wheels.

In issue 4/2000 Tour tested the 'old' Ksyriums and in issue 7/99 they tested wheels built with CXP33-rims.
Here are some of the data:
Weight(f/r) Inertia
Ksyrium 730/934 123J
CXP33 678/845 118J

The CXP33-wheels were this time too built with Sapim CX-Ray spokes (28/32) and Tune hubs.

Ksyrium-wheels both the 'old' version and the new SL don't seem to have any different performance then wheels built with OpenPro or CXP33-rims.

But there are two ways that the Ksyriums are different in:
Looks
Price

If the looks make them worth the price is up to the buyer to decide, but the buyer also clearly shows off that he pays extra for looks not performance.

Homebuilt alternatives

If you like the black look of the KSyriums you can try the following alternative:

Front
Hub: Nav AmericanClassic, black 68g  515SEK
Rim: OpenPro, black 425g 399SEK
Spokes: 32 Sapim CX-Ray, black 145g 736SEK
Nipples: Sapim Polyax, black 11g (incl)

649g 1805SEK

Rear
Hub: Tune MAG 200, black 209g 2477SEK
Rim: CXP33, black
DurabilityJofa
Oct 16, 2002 11:32 AM
Then, aesthetics. All this stuff is mildly interesting but arcane knowledge, of slight use only to those professional racers whose livelihoods depend on split-second advantages. They will already be keeping their jerseys zipped up and their mouths shut, practices which have as much aerodynamic effect as their choice of wheel rims.

Jofa
Agree with JofaLook381i
Oct 16, 2002 12:56 PM
The wheel science info is interesting, but I originally bought my K's for one reason: I understood that Lance chose them over his sponsor's wheels. That seemed like a good recommendation.

Now that I've used them for two years and about 10,000 miles (I've lost count) , I recommend them myself, because they have been smooth, confortable and bulletproof. Maintenance has involved wiping them down every so often. I have also seen a friend with the new K SLs continue to ride on his after a wreck that bent two or three of his spokes severely. He bent them back, wheel was still true, and rode another week and 500 miles before we parted ways.
info.......CARBON110
Oct 16, 2002 1:17 PM
The KYS that LA rode have a carbon rim that wont be offered to the public. His sponser ( Rolf) had issues with spokes breaking at the time. Rolf could not match the weight of a carbon Mavic wheel custom made for pros. Also Mavic as I understand it sponsers everyone almost. KYS are not good in te wind, according to Nimble wheelworks, due to the spoke notthe rim depth. They said that flat spokes are like, eggbeaters, in the wind but extreemly stiff. Hidden nipples on wheels seem to have an impressive aero effect. Deep dish wheels that are over 40mm seem to have an advantage especially if they are over 50 mm deep on the right course. Although, mavics Carbone wheelset weighs more tan a 1950 chevy, so I dont get that. Zipps 404 wheels are great weight and aero ... but it remains to be seen if they can hold up better than 2002 303's.
Of course....CARBON110
Oct 16, 2002 1:29 PM
After racing my A$$ off this year I learned a few things that changed my mind on wheels. Wheels are great to buy and make a bike look sexy. But, there arevery few, VERY FEW times yu break away from the group alone and sitting on someone else's wheel, wheter uphill or flat, will give you more aerodynamics than any weelset. Aero wheels are great for TT's but not that much help otherwise, unless your maybe doing alot of work in a fast paceline. For me, being 127lbs, weight and looks are more important. I can push a light wheel faster with less power than any aero wheel. Of course, lightweight,aero and goodlooking are nice too :)
I agree 100%. I'll take light, quick accelerating wheels any dayTig
Oct 17, 2002 6:58 AM
If I need better aerodynamics, I'll just bend my elbows a little more and zip up the jersey. At 132 lbs, I'll take a wheel with decent aerodynamics that is much lighter than a pair of K's.

I'll stick with 14/15/14 spokes instead of 14/17/14's, even though I wouldn't break the lighter, more aero Revolutions. I'd rather have 30 extra grams in a set of spokes that I can count on. Wheel failures are a pain at best, and deadly at worst.
I don't believe that's rightaeon
Oct 16, 2002 6:54 PM
I'm pretty sure Lance rode Lightweight brand wheels in the climbing stages of the tour, and these are the deep carbon wheels you speak of. Similar to the ADA's that Jalabert rode, they're completely custom, cost $3000 (which the racer pays) and weigh about a kilo per set.

This year for the flat stages it was Bonti wheelsets, but in years past he has used Rolf and Mavic.

www.lightweightwheels.com

P.S. Nimble probably disclaims the K's becuase they want you to buy the Crosswind's. I don't think there have really been any objective testing of different spokes and lacings yet.
Sigh......CARBON110
Oct 17, 2002 4:16 AM
Everyone who keeps up with the Tour knows LA used Lightweight wheels in 01 and 02 Tours for the climbing stages. He did as well in the Tour De Swiss, but like I said, unless you are out front it really isnt much help. Lance rides alot out front and people like J.Cobb have done studies to show aero is good when you are ALONE like in a TT or on a climb break away. Thanks for confirming his use of Bontrager wheels... no kidding. As far as Nimble goes I am pretty sure they know what they are saying after the words " wind tunnel testing " They are located in Austin TX you know. There has been lots of objective testing on aerodynamics of wheels spokes and lacing...this how most wheels are designed. Go to google and do a search. The only company that perhaps does not test is shimano...those 7700 wheels are anything but aero. I'm also sure that the Mavic Carbone wheels they use in the Pro ranks are alot nicer than the ones we use.
But did he use carbon Ksyriums in the 2000 TdF?Look381i
Oct 17, 2002 6:49 AM
I bought my K's in the fall following the 2000 TdF. The news then was that he had spurned his sponsor wheels (Rolf?) for the then new Ksyriums. I wasn't aware that K's were ever made in a carbon version. I read all I could find about the new K's and Lance's use of them at the time. I never saw a mention of their being different in design from the ones I bought.
But did he use carbon Ksyriums in the 2000 TdF?CARBON110
Oct 17, 2002 7:08 AM
Hey Look381,
According to Lance's mechanic for the 2000 TDF, mavic gave the usps team carbon Kysriums as well to the pro peloton that would not be offered to the public. You can call Dave at fastrackbicycles.com and ask him about it. Lance never used Rolf wheels in the TDF... EVER. In 1999 he used some special wheels that may be a mavic or at least was a custum wheel. Remember, up until about 6 years ago, all the peloton road bikes were custom stuff from sponsers. It was expected that the bikes pro road racers have are lighter, more stiff, etc etc..now bike manufacters have access to more cost effective and stronger materials and better ways to make it economic to the public for boostng sales.
I found a reference . . .Look381i
Oct 17, 2002 7:06 AM
Dave Lettieri, Lance's personal mechanic for the 2000 Tour de France:

" The Road Bike was a white OCLV 120 Full Dura Ace with Mavic Cosmic wheels (for the flat
stages). Other team components included Deda stems/bars, Hutchinson Tubulars, and Vetta
computers. This weighed on a digital scale 8.3 kilos [18.3 lbs]. The bike had 53x39 and 11x21
gearing.

" The Climbing Bike was the grey colored OCLV 110 (lighted layers of carbon fiber), and a
super light carbon fork with Alum steerer tube. Complete Dura Ace group with ti bolt kit.
Downtube left shifter and Special "Light" Ksyrium wheels. This bike weighed 7.45 kilos [16.4
lbs] - Tyler's weighed 7.3 kilos [16.1 lbs] with a smaller frame and lighter pedals - 53x39
11x23 gearing.
. . .

" Generally the riders would use standard Ksyrium wheels. A couple of riders, Lance, George,
and Eki were using Cosmic for the aerodynamics during the flat stages. When the team was
in the jersey defense mode, they all used Cosmics. For the climbing days the all used
Ksyriums with Lance, Tyler, and Kevin using the Ksyrium lights (these won't be available to
the public)...."

Lancearmstrong.com

Does the special light version of the K's means carbon? Or does it mean what eventually became the SLs, with milled rims, etc?
Carbon Mavics?filtersweep
Oct 17, 2002 8:36 AM
What is a "carbon" mavic? An aluminum rim with a carbon fairing? Have they ever made a proper carbon rim? I don't get it either...
Carbon Mavics?CARBON110
Oct 17, 2002 11:04 AM
As I remember, the rim was carbon.
Carbon Mavics?filtersweep
Oct 17, 2002 11:37 AM
Don't Carbones have an aluminum rim?
lousy science.blehargh
Oct 16, 2002 10:01 PM
man i hate it when ppl don't do proper research it just makes the poster look silly.

aerodynamics aren't measured in grams and moments of inertia aren't measured in Joules.

makes it hard to take anything else he states for "fact".

-d
Doesn't J = Joules?Look381i
Oct 17, 2002 2:02 AM
As in "Ksyrium 730/934 123J CXP33 678/845 118J"

Weren't the grams pertinent to the mass of the built wheels?

The original poster from the other website was just passing on data from published tests.
Doesn't J = Joules?blehargh
Oct 17, 2002 10:32 PM
i Tour also tested the aerodynamics of the wheels in Mavics windtunnel. The wheels have almost the same aerodynamics: Ksyrium SL: 251g, OpenPro: 258g ie less then 3% difference

isn't that g for grams? i think a coefficent of drag is more the measurement

yes. j == joules, but moment of inertia, basically rotational inertia, is measured in gm^2

what's the point of talking about these numbers if you don't know what they mean? pointless.

-d
Which is your point?Look381i
Oct 18, 2002 5:07 AM
Was it:

(1) The original study was improperly designed and/or measured. I thought that was your first point. The question then is whether the comparative data -- suggesting that one wheelset has better or worse performance than another -- are utterly unreliable.

or (2) The data are reported improperly but the comparisons are still valid. If this is the case, then I suspect most of us who are not trained as engineers can understand that a small percentage difference should matter less to us than a large one, and that even "large" ones may have no bearing on our own real world cycling.

or (3) The original poster should not have repeated published findings if he did not understand them, whether they are correct or not.

or (4) I --and people like me who are not properly trained as engineers -- should not ask questions about either the orginal study or the original posting.

or (5) I --and people like me who are not properly trained as engineers -- should not question you.

or (6) Some combination of the above.
Which is your point?blehargh
Oct 20, 2002 5:39 PM
I think you misunderstood me there. i didn't mean that you specifically shouldn't talk about the numbers. i meant it in a general sense. that people should have a general sense of skeptism when people start publishing numbers.

so sorry, i hope you didn't think i was attacking you personally. and i'm not trying to to attack non engineering folk either. in fact i think it's the non engineering folk who should be the most skeptical and ask the most questions when numbers are posted.

anyways my overall point is your first one. that you can't trust anything the study concludes cause the numbers that they base their conclusions on are faulty.

anyways, hope this clears up what i was trying to say.

-d