Jay Beattie said:
"the blur" <[email hidden]> wrote
in message news:[email hidden]...
Quoted message said:
hi-
i'm looking to build up a set of fast 700c road wheels (aero)
that i'll
Quoted message said:use every day in fast group rides. i think i'll use aero
bladed spokes
Quoted message said:like DT aerolights or sapim cx- ray. i can find hubs with
20/24
Quoted message said:drilling (front/rear) but where do i find some aero rims that
are
Quoted message said:drilled that way? all i can find are mavic cxp33's with 28
holes. any
Quoted message said:suggestions for sources, or other rims to recommend? how about
non-proprietary paired spoke rims? also, any opinions on
bearing drag
Quoted message said:for different hubsets? i'm looking at some american classic
hubs.
Quoted message said:opinions? how about white industries? thanks for opinions
(trying not to spend $800 for rolf prima vigors)
extra questions: the concept of an aero wheel-is it low spoke
counts/bladed spokes that make the difference, or the deep
rim-or both?
Quoted message said:are the rims deep and stiff so you can use less spokes, or is
the deep
Quoted message said:rim important in a slipstream/turbulence decreasing effect? or
is the
Quoted message said:main effect low spoke number?
why is there no data on wheel efficiency? taking into account
bearing
Quoted message said:seal drag, wind efficiency, weight distribution (hub vs rim)
etc. has
Quoted message said:anyone taken different wheels and just "rolled them down an
incline"
Quoted message said:and tabulated that?
--
the blur
Dear Mr. The Blur,
Putting aside for the moment the prudence of a 20/24 spoke wheel,
one choice is the Velocity Deep V.
http://velocityusa.com/rims/road-rims.php . If I were building a
semi-aero, ultra-light wheel with bladed spokes, however, I would
use an Aerohead OC 28 hole rim for the rear. By the way, there
is plent of data bearing on your questions, which Carl Fogel will
undoubtedly dredge up from the bowels of the internet. -- Jay
Beattie.
Dear Jay,
[Bullfrog sees red flannel waving, bullfrog's tongue lashes
out.]
http://damonrinard.com/aero/aerodynamics.htm
The link above to an article by Rainer Pivit has a nice
table of potential aerodynamic improvements due to taping
shoelaces, shaving legs, and so forth.
It indicates that switching to one particular front aero-rim
might save 44 seconds in a 65-minute 40km ride, while a
similar rear aero-rim might save another 18 seconds.
Such small improvements are probably visible only in
predictions, not in averaged test runs, since the wind (and
the rider's breakfast) will normally cause more variation
than 1 minute out of 65 on an outdoor ride:
Out of curiosity, I put 37 km/h for a 65-minute 40 km ride
into this calculator, using a default rider on a triathlon
bike:
http://www.kreuzotter.de/english/espeed.htm
With no wind, the prediction is 213 watts, 64:51.9.
With a 1 mph headwind, the same 213 watts takes 65:56.0.
That's about 63 seconds longer--roughly the 66 seconds that
the other page predicts might be saved by an aero rim.
Carl Fogel
