lenticular vs flat disc?
Matthew Thomas
extra (200grams or so) weight? Or is there really a difference at all? Or
is a 3 or 4-spoke just as good? Or should I just forget the whole thing and
go deep dish? Help!
salud,
Matt
Seth Moore
any further.
Seth Moore
Matthew Thomas wrote in message <7vcvhh$dle$1...@agate.berkeley.edu>...
Matthew Thomas
And I take it by your choice of disc wheels that a flat disc is just fine.
salud,
Matt
Seth Moore wrote in message <381a18cd$0$4...@news.voyager.net>...
JasonOGK
doing Powerman Zofingen, (90 mile bike ALOT of climbing) dont use any disk, but
rather composite wheels (3 or 4 spoke) or deep dish (Hed, Zipp etc).
As far as a lenticular disks, on paper and in the wind tunnel, they are faster
than flat disks. the Lens shape creates lift in side and cross winds. A Hed
Lens disk haslower drag #s than a Zipp, This is supported by the following data
HED disk (lenticular) 0.036 0.020 -.004 -.005 0.000 0.001 -.003 -.005
ZIPP 950 disk (flat) 0.036 0.023 0.013 0.017 0.018 0.017 0.016 0.016
The fastest setup is the most NON IDEAL, double disks, the ynext best is if the
course is flat to rolling (no major climbs) go disk rear double deep front.
Dont let weight be a factor. Let the aerodynamics make your decision. I find
that once you get a disk moving it almost feels as if it is shoving you foward.
go to
www.bsn.com/cycling/wheelaerodynamics.html for more info or email me if you
have further questions
Seth Moore
Matthew Thomas wrote in message <7vdhdg$gju$1...@agate.berkeley.edu>...
"Why is the Deep better than a composite 3 or four spoke?"
HED Deep is reported to be more aero at yaw angles approaching 15-20 deg.
which here in Ohio seems to be representitive of usual wind conditions. I
would suspect that rotating drag of the Deep is also less especially in a 12
aero spoke configuration.
"And I take it by your choice of disc wheels that a flat disc is just fine."
Conflicting aero data on flat versus lenticular discs. I have a Zipp, have
tried a HED and have purchased and tried about 12 Corimas for our club
members. I feel that the Zipp and Corima's offer superior construction. Just
my $ .02 worth.
Seth Moore
Matthew Thomas
What about handling in a crosswind? Aren't double deeps and and composite
spoked wheels a bit difficult to handle? Do high winds ever lead you to not
ride a disc at all?
Seth Moore
Matthew Thomas wrote in message <7vfm92$nni$1...@agate.berkeley.edu>...
I have never had a problem with a rear disc. If it's so windy I can't ride a
rear disk I probably wouldn't race (never ridden in Hawaii). I have used a
front HED CX, HED Deep and a Zipp front disc. On days with absoulutely no
wind (and I mean no wind) I like the front disc. Anything over 3-5mph wind I
Iove the Deep. No reason to ride a CX anymore.
Seth Moore
JasonOGK
horrible, and I did not have any problems what so ever as far as stability.
jason
johnn...@my-deja.com
Where did you get that information? Most test results I've seen (and
several tests are listed at Damon Rinard's site) indicate that the Zipp
950 is faster at lower yaw angles while the HED (and other lenticular
designs) is faster at higher yaw angles.
Thus the faster wheel would depend on the direction of the wind.
I would agree that weight is not that big a concern. Pro TdF riders use
heavy Campy and Mavic disks even in the mtn time trials.
I would also agree that handling is not that big of an issue, though it
may depend on the size of the rider. I use a Zipp disk, am 6'0" tall,
165 lbs, and have no handling problems.
Sent via Deja.com http://www.deja.com/
Before you buy.
cog...@grecc.umaryland.edu
values), not drag forces. Drag areas are often more useful (since they
are velocity independent), but the only time that I have seen the data
actually presented that way was in the aero wheel article by Greenwell
et al. IIRC, they didn't actually measure the frontal area of various
wheels, but used a derived, fixed value to do the calculation - that may
explain the discrepancy between the data Jason posted and e.g., that
found on Damon's website.
Andrew Coggan
johnn...@my-deja.com wrote:
> Where did you get that information? Most test results I've seen (and
> several tests are listed at Damon Rinard's site) indicate that the
Zipp
> 950 is faster at lower yaw angles while the HED (and other lenticular
> designs) is faster at higher yaw angles.
shaun
air travels faster over a curved surface than it does a flat surface
and thus produces a lower pressure area around the wheel. It is the
same principle that generates lift on an airplane wing. The number of
spokes alone on the front wheel will not dictate it's aero
performance. As stated above, the shape is what counts and how much
surface is in the way of the airflow to turbulate it. As stated by
others, the course your racing should guide you in your final
decision. If it is flat, always take the weight penalty in favor of
the aerodymanics.
cog...@grecc.umaryland.edu
> a curved disc will always be more aerodynamic that a flat disc because
> air travels faster over a curved surface than it does a flat surface
> and thus produces a lower pressure area around the wheel.
Ahhh, that's why they have to make the things out of high strength
carbon fiber...otherwise the vacumn created by the air rushing rapidly
over both curved sides would pull the two halves of the wheel apart! ;-)
Andrew Coggan
JasonOGK
This is the site I recieved my info from