I wanted to post an interesting report we commissioned from Cycling Power Lab. It’s a bit different than the typical aero drag data. Cycling Power Lab applied new mathematical/physics models to evaluate real world course, weather and component data with a goal of answering performance related questions. The report evaluates the 2012 Tour of California time trial course and the 2012 US Pro time trial course. The report compares our 58 and 85 wheelsets against similar rim depth brand modles in the market today. I believe this report advances component performance analysis. If you have interest in viewing these reports, click on the link: http://www.williamscycling.com/Cycling-Power-Lab-Analysis_ep_46.html
Seems a little funny that the lightest wheel in the group (stinger 6) has the lowest amount of time savings due to weight. But interesting work nonetheless, thanks for posting it.
I’ve ridden Williams wheels and they really are a great deal for the money. I’ve found them to provide significant aero and weight benefits while still being sturdy enough to race hard in the real world (read: potholes!).
I would pick a few nits with the data:
I might like to see them get empirical wind data using an iBike, but the theoretical is a start.
300W/70kg is not realistic for a ProTour (closer to 5W/kg) or domestic pro rider. They will be going much faster, and so have reduced yaw angles. This could affect the results. Slower riders (or those doing longer TTs, like triathletes) need a wheel that is better over a wider range of yaw angles.
$1100 Ksyriums are a little pricey. I would say the ones that are ~$600-700 (Elites?) would be a more realistic comparison for a baseline wheel.
Overall a cool study and great support for a great product.
I will have Rob, the data engineer from www.cyclingpowerlab.com respond to the questions above. I encourage you to visit cycling power lab to learn more about his company. I find his website fascinating.
As for Williams, I think it is important to post a transparent research report. I also believe this is the first report of it’s kind that takes raw data and converts it into real world performance data.
We don’t pretend to have the fastest wheels on the market. Our goal at Williams is to get athletes “in the game” at a very attractive price point using fantastic components such as Sapim CX-Ray spokes, our new tech carbon resin and layup, 6/60 hubs etc… We want athletes to realize that with WIlliams, you will race on quality wheels at 1/2 to 1/3 the price point. If you are looking to squeeze ever second out of your equipment and price is no concern, there are other wheel solutions. If you willing to give up a few seconds and save $1,000 to $2,000 on a set of wheels, then Williams is a real option.
Thanks. I’m in the market for new wheels this year and will give yours some consideration. Looking at the $ per watt cost of higher end wheels is an interesting approach and indeed makes your wheels more attractive.
I think you’ll find that most of those companies wouldn’t recommend comparing different tunnel trips, but in the case of wheels where there are 2-3 different set of data you can at least see the outliers.
I wonder if the williams data is without tares removed, or with particularly un-aero tires, given that usually the low yaw numbers are closer than that.
The williams wheels may be better than their own marketing here indicates =)
Some good questions. As the author of the report I will try to answer them.
The Williams wheels were tested with Vittoria Open Corsa CX Clinchers in the 23mm variant. Not the narrowest or most aero option (as is reflected in the numbers) but I think a fair representation of what many riders use habitually. The comparison data is from a variety of sources - wheel manufacturers themselves and third party testers such as Tour Magazine. The numbers (our database of component drag data compiled over time from numerous internet sources) can all be reviewed here: http://www.cyclingpowerlab.com/ComponentAerodynamics.aspx In the comparison cases we usually dont know the tire involved (but assume that manufactuers err towards narrower variants) - in an ideal world everybody would be as explicit with specifics as Williams who volunteered their data some time ago before suggesting this project.
We are forced to balance the limitations of comparing data from different sources and tests with the cost and impracticality of everybody trying to retest everything. In another ideal world we’d love to manage an independent database of component drag data with well defined details and controls around data submitted or at least to receive further detailed submissions from other manufactuers.
The “typical alloy” wheel refers to a Mavic Ksyrium. The price point of USD1149 is the current list price for a Ksyrium SLS.
The choice of 300 watt power output in the “time on course” analysis is to give meaning for amateur riders. We could have run this analysis assuming pro riders clocking 30mph but this leaves all kinds of questions for most wheel consumers who dont have that power and speed.
