Originally Posted by
The Smokester
Hermes,
I have been wanting to ask someone about the effectiveness of "aero" wheels. Has someone quantified and compared the power requirements for various wheels and speeds in this regard? Now that you have a power meter can you do some comparisons?
Unfortunately, it seems to me it takes, at a minimum, intercalibrated power meters on all wheels sets. But still, maybe you can point us to some relevant, quantitative information?
Inquiring minds want to know.
Thanks.
Here is some test data from a German wheel company, Xentis, using a crank based power meter at a velodrome. I have the Easton Tempest II which are similar to the Zipp 404. Note that the power savings is based on 28 mph.
Watt savings over a 32 round-spoked Ambrosio Nemesis at 45kmh/28mph
Vuelta carbon pro -38 Watt
Xentis mark 1 -37 Watt
Zipp 808 -36 Watt
Bontrager Aeolus -34 Watt
Zipp 999 -29 Watt
Ritchey carbon -28 Watt
Easton Tempest II carbon -29 Watt
Lightweight TT -27 Watt
Mavic Cosmic Carbone -22 Watt
Corima 3 spoke+Disc -20 Watt
Corima 3 spoke -20 Watt
Lightweight 12/20 -19 Watt
Corima Aero -19 Watt
Tune Olympic Gold -16 Watt
Nimble Crosswind -5 Watt
A 30 watt savings is a lot of power BUT it depends on how much you are producing at the time. 28 mph for me is about 370 watts or under 10%. Most riders cannot generate that speed very long if at all. For many group rides the guys setting tempo are riding 20ish. So if you take a pull, an aeor set of wheels may save you are few watts. Hardly enough to make a difference of feeling good taking a pull or not.
In the pack where there is turbulent air, the aero effect is minimized even more. So if you are having trouble hanging with a group, faster wheels will probably not make any difference.
Where aero wheels make sense is if you race and get in break aways. A break away for all intent and purposes is a time trial. You will spend more time riding solo at higher speeds. More aero wheels will make a difference to an extent.
Cervelo has a good discussion on aerodynamics on their website. HED has some very good interactive graphs on aero drag coefficients for their wheels as well as competitors.
The real beauty of the power meter is that it shows how much power you make. I realized how much I was short in some areas and how much I have improved in a short period of time. IMHO, this is where the action is for improving performance. Hundreds of watts are on the table to be picked up versus a few by better wheels and bicycles.