aero drag numbers

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aero drag numbers

Post  kumagako on Mon Nov 22, 2010 10:25 am

i took this data from the HED website...


ordinary alloy wheels
vs
zipp 404 clincher
vs
zipp 404 tubular

*surely the deeper rim is faster than the a shallower one. One thing to notice is that a tubular is faster than the clincher. And also increasing the yaw of the wind increases the drag numbers.


zipp 404 tubular
vs
zipp 808 tubular
vs
zipp sub9 disc

*same pattern with the deeper rim much faster. The non discs drag numbers noticeably increases with the increase of wind yaw unlike the small increase for a disc. One peculiar thing is that the 808s and discs are similar around 9 degrees yaw.


zipp sub9 disc
vs
HED jet disc (cheaper model)
vs
HED stinger disc (highest end)

*the drag numbers maybe biased but the drag number curves surely exhibit the exact response. HED discs are mainly different by having a bigger toroidal bulge than the ZIPP discs. I think the Stinger has a bigger bulge. As observed from the Stinger is that it has a negative drag at 10-15 degrees. Too bad the Zipp Super 9 is not part of the test.

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Re: aero drag numbers

Post  kumagako on Mon Nov 22, 2010 10:41 am

so how do we go faster???

1. budget to buy a disc wheel of course

2. choose what disc to buy

Since weather condition (wind direction) differs on the race course, the best disc to choose is the one with a flatter response.

I think the Stinger disc (or any other disc with the same response) with a dramatic change in drag numbers from at the 15 degree pivot can cause a loss of rhythm and knockoff some speed causing a loss of momentum.

The Stinger disc is only good for fast riders riding beyond (estimate) 45kph. For the wind yaw angle (resultant angle) is smaller due to the fast speed.

Physics dictates that the same wind condition the resultant yaw angle is much bigger for a slower rider.

3. buy the disc

of course bring your friends when you go shopping so they can experience the excitement

4. consistently and systematically train to improve

the ultimate answer and there might be no need for the disc
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Re: aero drag numbers

Post  Makoy on Mon Nov 22, 2010 12:45 pm

Expensive stuff... beelat
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