Rim profile
Wantagofast
wheels or their implementation of the Zipp 58MM (Zipp404) rims.
Trying to balance the aerodynamic benefit with usability for most road
races.
See many of the euro pros riding on high profile rims in the past TDF.
I race in Texas, so hills aren't as plentiful as wind is.
Any suggestions?
Thanks
Qui si parla Campagnolo
wheels or their implementation of the Zipp 58MM (Zipp404) rims.
Trying to balance the aerodynamic benefit with usability for most road
races. >><BR><BR>
Like I mentioned on RBR-find a good wheelbuilder, get some Reynolds(formerly
LEW) rims, DA or Record hubs and have that good wheelbuiulder design a wheelset
just for you-
Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"
Andy Coggan
"Qui si parla Campagnolo" <vecc...@aol.com> wrote in message
news:20030102090200...@mb-ff.aol.com...
> << Trying to decide whether to get the new Cane Creek 2003 21MM carbon
road
> wheels or their implementation of the Zipp 58MM (Zipp404) rims.
>
> Trying to balance the aerodynamic benefit with usability for most road
> races. >><BR><BR>
>
> Like I mentioned on RBR-find a good wheelbuilder, get some
Reynolds(formerly
> LEW) rims, DA or Record hubs and have that good wheelbuiulder design a
wheelset
> just for you-
Unless Reynolds has dramatically changed the rim profile, this would be a
major waste of money. The original LEW rims weren't particularly
aerodynamic, given their depth.
Andy Coggan
Andy Coggan
news:3e13b308$1...@nopics.sjc...
Personally, I find rims that are about 30 mm deep and have a rounded inner
profile (e.g., Velocity Deep V) to be about the best all around compromise
between aerodynamics and stability. That is, such a rim provides a
significant aero benefit over classical box section rims, but (at 150 lbs) I
can use such wheels under practically all conditions without any significant
annoying twitchiness and definitely without ever struggling with control.
You might want to look for something along the same lines, e.g., the Zipp
303 wheels (if you've got the $$). If for some reason you're stuck with/on
Cane Creek wheels (sponsorship?), then I'd probably favor the deeper rims
*provided* A) you've got other wheels to use for training or windy races,
and B) you weigh at least as much as I do.
Andy Coggan
Bruce Gilbert
projects. The best advice that I can give you is to try a pair of wheels
built with these rims. Listen to Peter when he tells you to find a good
wheelbuilder. There are so many ways to customize and tweak the build with a
given set of spokes, lace pattern and the same rim. The deep rims may not
yield the best performance you your particular circumstance. Consider the
alternatives, it may be well worth it. Also keep in mind that in the bike
business, one manufacturer can supply a host of apparent competitors with
their products...
Bruce
"Andy Coggan" <aco...@earthlink.net> wrote in message
news:DUXQ9.8138$134.9...@newsread1.prod.itd.earthlink.net...
Qui si parla Campagnolo
be
>a
>major waste of money. The original LEW rims weren't particularly
>aerodynamic, given their depth.
46mm-don't get above statement-
Wantagofast
failure rate using titanium spokes. The rim would get wavey due to the
extra high tension need by the ti spokes, so my options are a new 21MM rim
or the 58MM (Zipp404) rim. I weigh a bit more than you, so weight issue you
point out should be less of a problem for me.
"Andy Coggan" <aco...@earthlink.net> wrote in message
news:DUXQ9.8138$134.9...@newsread1.prod.itd.earthlink.net...
Andy Coggan
> I would too, but CC discountinued their 30mm rim (Zipp303 rim) due to a
100%
> failure rate using titanium spokes. The rim would get wavey due to the
> extra high tension need by the ti spokes, so my options are a new 21MM rim
> or the 58MM (Zipp404) rim. I weigh a bit more than you, so weight issue
you
> point out should be less of a problem for me.
I thought the 303 rims were 38 mm deep? And why would Ti spokes require
greater tension? (Honest questions.)
In any case, if you weigh more than I do then you'd probably be okay with
even 58 mm deep rims for most of the year, at least in the parts of Texas
I've lived in (Austin and Galveston). Even at 150 lbs I've only *really* had
trouble controlling such a wheel once in many years, but I think the
requirement for stability is different in a sub-hour TT vs. a multi-hour
mass start road race...hence my suggestion that you might want to have
something more stable to use as an alternative when the occasion calls for
it.
Andy Coggan
Andy Coggan
> acoggan->Unless Reynolds has dramatically changed the rim profile, this
would
> be
> >a
> >major waste of money. The original LEW rims weren't particularly
> >aerodynamic, given their depth.
>
> 46mm-don't get above statement-
What I meant was that although the LEW rims appeared aerodynamic, due to
their depth, when tested in the wind tunnel they weren't all that fast,
especially considering the price. To state it another way: there are many
factors influencing how much drag a rim (wheel) generates, with rim depth
being only one.
Question: with normal (aluminum or even steel) rims, maximum strength of the
wheel is achieved when spoke tension is quite high relative to what the rim
can tolerate (or so I understand it). However, typical carbon fiber rims are
exceedingly stiff and strong in their own right - does increasing spoke
tension therefore pay as large a dividend, or do the spokes just need to be
tight enough to keep the hub centered in the rim and to prevent the tension
from falling to zero in the load affected zone?
Andy Coggan
Tom Compton
"Andy Coggan" <aco...@earthlink.net> wrote in message
news:DUXQ9.8138$134.9...@newsread1.prod.itd.earthlink.net...
> profile (e.g., Velocity Deep V) to be about the best all around compromise
> between aerodynamics and stability. That is, such a rim provides a
> significant aero benefit over classical box section rims, but (at 150 lbs)
I
> can use such wheels under practically all conditions without any
significant
> annoying twitchiness and definitely without ever struggling with control.
> You might want to look for something along the same lines, e.g., the Zipp
> 303 wheels (if you've got the $$). If for some reason you're stuck with/on
> Cane Creek wheels (sponsorship?), then I'd probably favor the deeper rims
> *provided* A) you've got other wheels to use for training or windy races,
> and B) you weigh at least as much as I do.
I don't see that stability would be related to weight. Wind acting on a
deep section front rim gives a greater moment about the steering axis than a
box-section rim, and I believe this is the cause of handling differences.
I have been riding deep section rims for many years and have found them to
be stable in constant wind speeds up to 40 mph. The limitation seems to be
sudden gusts. I have not found stability to be a problem until the gusts
reached about 40 mph. However, a rider that is inherently unsteady may be
affected more.
Tom Compton
www.AnalyticCycling.com
Mark McMaster
You basically answered your own question. A wheel can
support loads up to the point that the spokes become slack.
The higher the spoke tension, the more load the wheel can
bear before the spokes slacken. Therefore, the wheel will
be strongest with the highest tension that they wheel can
bear. (Note: In "traditional" wheels with a higher number
of spokes, the spoke tension is limited by the strength of
the rim rather than by the strength of the spokes).
That being said, for most wheels there will be range of
tensions between the maximum tension the rim can bear and
the minimum tension required to keep the spokes from
slackening under the maximum load the wheel will
experience. The size of this range will dependent on a
number of factors, but the more flexible the rim and the
fewer (and thicker) the spokes, the narrower the range of
acceptable tension will be.
So, I guess the answer to your question is that load bearing
capacity of wheels with deep, stiff rims (carbon fiber or
metal) will still be limited by the the point at which the
spokes slacken, so higher tensions (within the limits of the
rim) will result in a stronger wheel.
Mark McMaster
MMc...@ix.netcom.com
Mark McMaster
>
> "Wantagofast" <som...@someone.com> wrote in message
> news:3e146...@nopics.sjc...
> > I would too, but CC discountinued their 30mm rim (Zipp303 rim) due to a
> 100%
> > failure rate using titanium spokes. The rim would get wavey due to the
> > extra high tension need by the ti spokes, so my options are a new 21MM rim
> > or the 58MM (Zipp404) rim. I weigh a bit more than you, so weight issue
> you
> > point out should be less of a problem for me.
>
> I thought the 303 rims were 38 mm deep? And why would Ti spokes require
> greater tension? (Honest questions.)
They wouldn't require extra tension. In fact, due to their
extra elasticity, you might be able to get by with a little
less tension. (Not that this is an endorsement of titanium
spokes - they have a number of additional problems, and tend
to be less reliable than stainless steel).
Mark McMaster
MMc...@ix.netcom.com
dianne_1234
> What I meant was that although the LEW rims appeared aerodynamic, due to
> their depth, when tested in the wind tunnel they weren't all that fast,
> especially considering the price. To state it another way: there are many
> factors influencing how much drag a rim (wheel) generates, with rim depth
> being only one.
Yep, the LEW wasn't as good as a lot of people thought.
But the deep Reynolds rim is a different shape. Wider tire bed and
flatter sides to the V than Lew, IIRC.
> Question: with normal (aluminum or even steel) rims, maximum strength of the
> wheel is achieved when spoke tension is quite high relative to what the rim
> can tolerate (or so I understand it). However, typical carbon fiber rims are
> exceedingly stiff and strong in their own right - does increasing spoke
> tension therefore pay as large a dividend, or do the spokes just need to be
> tight enough to keep the hub centered in the rim and to prevent the tension
> from falling to zero in the load affected zone?
>
> Andy Coggan
All else equal, as the rim's radial stiffness increases, the drop in
spoke tension in the load affected zone (for a given load) is less
compared to a wheel built with a more flexible rim. That's because the
greater bending stiffness of the deep rim takes up more of the load,
sparing the spokes a bit. Deep rims made of carbon are stiffer still.
But even the stiffest deep carbon rims are orders of magnitude more
flexible (radially) than even one spoke, so the spokes still bear
nearly all the load on the wheel.
Basically, the rules for wheel strength haven't changed for wheels
built with deep carbon rims, just the fraction of load born by each
component has shifted a little (emphasis on little). I make spokes in
carbon wheels as tight as they would be in other wheels. That is,
tight.
Kraig Willett
news:6B0R9.8524$134.9...@newsread1.prod.itd.earthlink.net...
> news:20030102110455...@mb-ck.aol.com...
> > acoggan->Unless Reynolds has dramatically changed the rim profile, this
> would
> > be
> > >a
> > >major waste of money. The original LEW rims weren't particularly
> > >aerodynamic, given their depth.
> >
> > 46mm-don't get above statement-
>
> What I meant was that although the LEW rims appeared aerodynamic, due to
> their depth, when tested in the wind tunnel they weren't all that fast,
> especially considering the price. To state it another way: there are many
> factors influencing how much drag a rim (wheel) generates, with rim depth
> being only one.
Depending on which data set one chooses to believe a case could be made
either way. Tire effects are important and are not often reported by the
researchers.
See:
for what I would deem the best currently available concept in traditional
rim profile design if one wants to go fast. Zipp owns the Haug interest in
the patent.
--
==================
Kraig Willett
www.biketechreview.com
==================
Qui si parla Campagnolo
carbon wheels as tight as they would be in other wheels. That is,
Be careful exceeding the recommended 90 kgf that Zipp recommends. It is easy to
pull a nipp thru the rim. The new Reynolds rim is 'rated' at 180kgf-our choice
for expensive, light weight carbon rims now. In addtion, an all carbon
clincher(for you nancy's out there;-)) is being tested now.
almost fast
> Be careful exceeding the recommended 90 kgf that Zipp recommends.
> It is easy to pull a nipp thru the rim. The new Reynolds rim is
> 'rated' at 180kgf-our choice for expensive, light weight carbon
> rims now.
Thanks for the info, Peter. Didn't realize those rims have such low
tension ratings!
I think I heard Bontrager designed their carbon rim for >900 pounds
pull through, and proof test each Bontrager carbon wheel to something
like 90% of spoke yeild (500 pounds? 600?)
almost fast
> See:
> http://tinyurl.com/1y15
> for what I would deem the best currently available concept in traditional
> rim profile design if one wants to go fast. Zipp owns the Haug interest in
> the patent.
I see lots of pictures there; are some prior art? Can you breifly
summarise the main features we should look for?
Kraig Willett
"almost fast" <almos...@yahoo.com> wrote in message
news:24794220.03010...@posting.google.com...
Claim 1 was what I was referring to:
"the ratio of maximum width of said rim to the intended tire diameter being
in the range of from 1.05 to 1.5".
The 404 implements this feature:
http://www.zipp.com/Wheelsets/404_clincher.html
since the hooks on the clincher are narrower in width than the maximum width
of the rim. The increasing section thickness of the rim sets up a favorable
pressure gradient downstream of the tire/rim junction. This feature
promotes flow reattachment which is beneficial for going fast in a variety
of wind conditions.
Doug Milliken
On Sat, 4 Jan 2003, Kraig Willett wrote:
> Claim 1 was what I was referring to:
>
> "the ratio of maximum width of said rim to the intended tire diameter being
> in the range of from 1.05 to 1.5".
>
> The 404 implements this feature:
>
> http://www.zipp.com/Wheelsets/404_clincher.html
>
> since the hooks on the clincher are narrower in width than the maximum width
> of the rim. The increasing section thickness of the rim sets up a favorable
> pressure gradient downstream of the tire/rim junction. This feature
> promotes flow reattachment which is beneficial for going fast in a variety
> of wind conditions.
Some of the HED deep rims are like this too (on purpose), max section
thickness is away from the tire/rim junction. It's also important to note
that the air passes the whole wheel, not just the leading edge, so
"downstream" (relative to the tire/rim crossection) can be in just about
_any_ direction depending on whether you are discussing the front, top, or
aft portion of the wheel.
-- Doug Milliken
www.millikenresearch.com
Kraig Willett
news:H87Mz...@freenet.buffalo.edu...
>
> On Sat, 4 Jan 2003, Kraig Willett wrote:
>
> > Claim 1 was what I was referring to:
> >
> > "the ratio of maximum width of said rim to the intended tire diameter
being
> > in the range of from 1.05 to 1.5".
> >
> > The 404 implements this feature:
> >
> > http://www.zipp.com/Wheelsets/404_clincher.html
> >
> > since the hooks on the clincher are narrower in width than the maximum
width
> > of the rim. The increasing section thickness of the rim sets up a
favorable
> > pressure gradient downstream of the tire/rim junction. This feature
> > promotes flow reattachment which is beneficial for going fast in a
variety
> > of wind conditions.
>
>
> Some of the HED deep rims are like this too (on purpose), max section
> thickness is away from the tire/rim junction.
Yep, it's Hed's Patent also.
>It's also important to note
> that the air passes the whole wheel, not just the leading edge, so
> "downstream" (relative to the tire/rim crossection) can be in just about
> _any_ direction depending on whether you are discussing the front, top, or
> aft portion of the wheel.
Yep, point taken.
The potential competitive advantage of this design only exists, though, when
the section of increased thickness lies downstream of the tire/rim
junction - and if I follow your terminology this can only occur somewhere in
the front half of the wheel.
All other V shaped rims (independent of tire width to max width ratio) will
benefit from the same effect of promoted reattachment of leading edge
separation (at yaw) on the aft portion of the wheel, no?