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Tips on carbon fiber WSD bikes?



 
 
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  #121  
Old January 5th 11, 10:21 PM posted to rec.bicycles.tech
thirty-six
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Posts: 10,049
Default Stiff Wheels

On Jan 5, 7:42*am, Chalo wrote:
Jay Beattie wrote:

Chalo wrote:


Those frames seem a lot less flimsy and flexible when they are
equipped with stiff wheels, stems, and cranks.


We need to have a discussion some time about stiff wheels. *I'm having
trouble conceptualizing how an adequately tensioned wheel would not be
radially stiff (not talking laterally). I hear talk from various racer
buddies about how one wheel or another is super stiff and a "secret
weapon" (another over-used advertising term) in sprints, etc., which
suggests to me that a wheel can be radially limp some how, at least
relatively speaking.


I'm talking about lateral stiffness. *I think you're exactly right
about radial (and torsional) wheel stiffness-- anything soft enough to
be discernible would be flimsy enough to break up almost
immediately.

I believe lateral flex in wheels, in small amounts, masquerades as
frame flex when pedaling hard. *More than a little bit of lateral
wheel flex destabilizes tracking and the wheels themselves, and
becomes identifiable as wheel flex.

If you live with Trevor on Planet Wherever, your bike might have
wheels that act as suspension in the vertical plane. *But in my
extensive observation, Earth wheels don't do that. *Misconceptions
along these lines by Earth cycle racers would be characteristic of the
heady blend of optimism, superstition, marketing bull****, ancient
lore, one-upsmanship and pipe dreams that passes for conventional
wisdom among that narrow demographic group.

Chalo


It is simply observable. My spokes are tensioned by three (or is it
four) turns of the nipples, yet the spoke(s) at the bottom of the
wheel come loose when riding at speed over bumps. This is a wheel
working effectively. With tighter spokes the speed over the bumps for
which a rider can maintain control is significantly reduced. The
cushioning iis improved by allowing the rim to deform and work. The
contact patch is elongated, so spreading the impact over a wider span,
efectively making the wheel radius larger when traversing the bump.
Hard wheels only work on smooth velodromes, and even then by
accident,not design.
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  #122  
Old January 5th 11, 10:35 PM posted to rec.bicycles.tech
[email protected]
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Posts: 106
Default Tips on carbon fiber WSD bikes?

Duane Hébert wrote:

I'm looking to replace my old road bike with a carbon fiber model.
My criteria a women's specific design, comfy for all day
riding, smooth riding, light weight, Shimano 105 components, and
preferably with three chainwheels.


Via the web, I've checked out the specs and reviews for following
bikes: Cannondale (Synapse Fem 5), Felt (ZW5), Giant (Avail
Advanced 2), Trek (Madrone 3.1WSD), or Specialized (Ruby Elite
Apex). I was hoping y'all might have some insights into these
bikes so that I could minimize driving all over the state (there
are no local dealers for most of these) to do the final fit
check-out and test ride. I don't know how comfort is specified on
a web page.


So here goes. Assuming equally good fit and tire size/psi - Do
any of these bikes stand out as more smooth riding? Do any of
these bikes stand out as more comfy for all day long cruising?
Does anyone have any idea how the weights compare for the same
size bike? Thanks for any help trying to trim down my list of
potential bikes.


NO! The comfort of a bicycle resides in its wheelbase and tires;
frames and wheels having practically no perceptible elasticity.
Therefore, test ride the bike and see if it fits your body: bars,
pedals, and saddle. You can't ask for more. If you chose a
suspension bicycle, you'll get speed instabilities that you won't
like. Get large enough tires 28-30mm cross section and brakes that
you like. That's where it's at!


Are you saying that all other things being equal, a bike with a CF
frame is not more comfortable than an aluminum frame? That a steel
frame is not more comfortable than an aluminum frame? Or am I
misunderstanding you?


I think what I wrote is unambiguous enough to not be misinterpreted.
You might review the FAQ on what holds the rim off the ground:

Subject: 8b.25 What holds the rim off the ground?

# What forces keep the rim of a wheel with pneumatic tires off the
# ground. It obviously can't be inflation pressure because it's
# uniform around the wheel.

# As has been mentioned, casing walls pull on the rim (or its
# equivalent) and thereby support the load. The tire casing leaves
# the rim at about a 45 degree angle, and being essentially a circular
# cross section, it is in contact with the rim over its inner quarter
# circle. At least this is a representative model. The visualization
# may be simpler if a tubular tire is considered. It makes no
# difference whether the tire is held on by glue or is attached to the
# rim as a clincher is. Either way the tire is attached to the rim, a
# relatively rigid structure.

So it is the angle of sidewall departure from the rim that gives
inflation pressure its load carrying abilities.
--
Jobst Brandt
  #123  
Old January 5th 11, 10:35 PM posted to rec.bicycles.tech
Steve Freides[_2_]
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Posts: 665
Default Tips on carbon fiber WSD bikes?

SMS wrote:
On 1/4/2011 4:00 PM, Steve Freides wrote:

snip

I think letting 5-10 lbs. of air pressure out of whatever tire you
find to ride harshly will make them equal in comfort.


Sheldon goes into all this. There's a myth that a wider tire will have
less rolling resistance than a narrower tire, but of course that's not
true when both are inflated to the proper pressure. The narrower,
higher pressure tire will have less resistance than the wider, lower
pressure tire, but the ride will be harsher than the wider tire.
Unless the rider is a racer, going with the wider tire is preferable.

The more I see of this thread, the more I'm convinced that we're all
very slow, and that this is obviously a troll. "Plushness?!"


Care to post a link to what you're reading on the site of the wonderful,
wacky, late Mr. Brown?

-S-


  #124  
Old January 5th 11, 10:35 PM posted to rec.bicycles.tech
thirty-six
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Posts: 10,049
Default Tips on carbon fiber WSD bikes?

On Jan 5, 9:15*pm, wrote:
Lou Holtman wrote:
I wouldn't demand that a road bike fit 32s, like mine does, but
if it fits 28s or 25s with fenders, it gives you options for
free. *Why not?
There are times of the year when 32s are really nice to be able to
install, and times when the lower rolling resistance of the
narrower 23s is desirable. *23-32 is not an unreasonable range to
insist upon for a road bike.
Scharf should realize that for a given casing construction, tread,
and inflation pressure, a wider tire has *less* rolling resistance.

and you should know that in that case the narrower tire is more
comfortable.


I think you might review what keeps the tire from bottoming when
inflated. *I think that is often overlooked in such discussions.



I think you may need to review your tone, this is not 1987 any more.


FAQ item:

Subject: 8b.25 * What holds the rim off the ground?
From: *Jobst Brandt

# What forces keep the rim of a wheel with pneumatic tires off the
# ground. It obviously can't be the air pressure because that's acting
# from top as well as from below.

# As has been pointed out, the casing walls pull on the rim (or its
# equivalent) and thereby support the load. *The casing leaves the rim
# at about a 45 degree angle, and being essentially a circular cross
# section, it is in contact with the rim over its inner quarter
# circle. *At least this is a good representative model. *The
# visualization may be simpler if a tubular tire is considered. *It
# makes no difference whether the tire is held on by glue or is
# otherwise attaches to the rim such as a clincher is. *Either way the
# tire is attached to the rim, a relatively rigid structure.
*--
Jobst Brandt


  #125  
Old January 5th 11, 10:44 PM posted to rec.bicycles.tech
thirty-six
external usenet poster
 
Posts: 10,049
Default Tips on carbon fiber WSD bikes?

On Jan 5, 12:28*am, James wrote:
Peter Cole wrote:
I have a couple of lugged steel, a couple of welded steel, and a couple
Cannondales. The Cannondales seem much more stable at high speeds. I'll
ride no hands at 60 kph.


Is that all?

Stability is more than just material based.

JS.


Quite so. My frames of racing geometry became ultra stable at very
high speeds. The more tourist frame, the one which I could fall
asleep on, riding at 16mph, although stable at speed, was not so easy
to set up coming into a corner and so felt unstable. Racing geometry
is best if you have masses of spare energy and really want to enjoy
the thrill of high speed cornering, but not very good when dusk is
setting in and you are unable to maintain 12mph.
  #126  
Old January 5th 11, 10:45 PM posted to rec.bicycles.tech
Duane Hébert
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Posts: 39
Default Tips on carbon fiber WSD bikes?

On 1/5/2011 4:35 PM, wrote:
Duane Hébert wrote:

I'm looking to replace my old road bike with a carbon fiber model.
My criteria a women's specific design, comfy for all day
riding, smooth riding, light weight, Shimano 105 components, and
preferably with three chainwheels.


Via the web, I've checked out the specs and reviews for following
bikes: Cannondale (Synapse Fem 5), Felt (ZW5), Giant (Avail
Advanced 2), Trek (Madrone 3.1WSD), or Specialized (Ruby Elite
Apex). I was hoping y'all might have some insights into these
bikes so that I could minimize driving all over the state (there
are no local dealers for most of these) to do the final fit
check-out and test ride. I don't know how comfort is specified on
a web page.


So here goes. Assuming equally good fit and tire size/psi - Do
any of these bikes stand out as more smooth riding? Do any of
these bikes stand out as more comfy for all day long cruising?
Does anyone have any idea how the weights compare for the same
size bike? Thanks for any help trying to trim down my list of
potential bikes.


NO! The comfort of a bicycle resides in its wheelbase and tires;
frames and wheels having practically no perceptible elasticity.
Therefore, test ride the bike and see if it fits your body: bars,
pedals, and saddle. You can't ask for more. If you chose a
suspension bicycle, you'll get speed instabilities that you won't
like. Get large enough tires 28-30mm cross section and brakes that
you like. That's where it's at!


Are you saying that all other things being equal, a bike with a CF
frame is not more comfortable than an aluminum frame? That a steel
frame is not more comfortable than an aluminum frame? Or am I
misunderstanding you?


I think what I wrote is unambiguous enough to not be misinterpreted.
You might review the FAQ on what holds the rim off the ground:


What's ambiguous is that you're saying that frames have practically no
elasticity but what about their ability to absorb vibration? We're
talking about what makes bikes more comfortable. My CF bike seems to
absorb the road vibration better than my last aluminum bike.


Subject: 8b.25 What holds the rim off the ground?

# What forces keep the rim of a wheel with pneumatic tires off the
# ground. It obviously can't be inflation pressure because it's
# uniform around the wheel.

# As has been mentioned, casing walls pull on the rim (or its
# equivalent) and thereby support the load. The tire casing leaves
# the rim at about a 45 degree angle, and being essentially a circular
# cross section, it is in contact with the rim over its inner quarter
# circle. At least this is a representative model. The visualization
# may be simpler if a tubular tire is considered. It makes no
# difference whether the tire is held on by glue or is attached to the
# rim as a clincher is. Either way the tire is attached to the rim, a
# relatively rigid structure.

So it is the angle of sidewall departure from the rim that gives
inflation pressure its load carrying abilities.


Yeah I got that.
  #127  
Old January 5th 11, 10:52 PM posted to rec.bicycles.tech
[email protected]
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Posts: 106
Default Stiff Wheels

Jim Rogers wrote:

It doesn't need to be exceptionally low because the rim distributed
spoke stiffness circumferentially if it isn't terminally radially
flexible, and fails to transfer the stiffness of spokes around the
rim.


Really? "Exceptionally low?" Are you sure it wasn't "exceptionally
exceptionally low?"


Exceptional, because such rims are not readily available because they
are useless for bicycling but apply to the circumstances described.

Please leave the fluff out of your writing. People who use such
modifiers are generally trying to use bluff and bluster to cover
their lack of understanding.


You're probably correct there. I suppose I should have mad my
response a few sentences longer to cover that problem.

At least that's what a "friend of mine" once told me. Are you sure

he was your-friend and not just a friend known to other bikies?
--
Jobst Brandt
  #128  
Old January 5th 11, 10:54 PM posted to rec.bicycles.tech
thirty-six
external usenet poster
 
Posts: 10,049
Default Stiff Wheels

On Jan 4, 11:33*pm, wrote:
James Steward wrote:
We need to have a discussion some time about stiff wheels. *I'm
having trouble conceptualizing how an adequately tensioned wheel
would not be radially stiff (not talking laterally). *I hear talk
from various racer buddies about how one wheel or another is
super stiff and a "secret weapon" (another over-used advertising
term) in sprints, etc., which suggests to me that a wheel can be
radially limp some how, at least relatively speaking.


http://www.sheldonbrown.com/rinard/wheel/index.htm


http://www.rouesartisanales.com/article-23159755.html


The first link is lateral stiffness. *The second link does talk about
frontal/radial stiffness and makes me wonder why anyone would buy a
wheel with spoke tension so low that it would allow rim deformation
under normal load -- particularly an uber-expensive carbon wheel. --


Lateral stiffness or lateral wheel collapse is dependent on rim
lateral stiffness, something that is not guaranteed by CF rims. *In the
days of yore, riders would spoke up track wheels for ultimate light
weight and end up with a pretzeled wheel at the first outing. *Those
were aluminum rims.


No wonder you have queer ideas if you thought that was normal.

Indeed. *My old set of CXP30 wheel were (as far as I could perceive)
radially stiffer than my current Open-Pro and Ksyrium wheels.


Radial stiffness relies mainly on spokes, because they must
elastically stretch to appear flexible or soft.


There ya go again, totally ignoring the lateral support a good spoke
assembly gives to a rim.

The difference became more noticeable in cornering on roads where there
is some corrugation. *The CXP30 wheels tended to skip across the road
whereas the Open-Pros and Ksyriums tend to ride the bumps a little more
softly and remain in contact with the road more.


Are you using the same tires and inflation? *You can't feel spoke
elasticity so I assume you are getting tire flex.


Bull****, the rim flexes, the amount by which and how a wheel sticks
to a road is determined by the quality of the spoke assembly.


As a friendly LBS owner describes it, the Open-Pros are like wearing
slippers by comparison.


Sounds like a good sales talk!

The CXP30's were bullet proof, I guess reasonably aero, but fairly heavy.
After 10 or so years of not racing, I started again last July with the
local veteran club. *I've won a few A grade road sprints on the Ksyriums
now, and for someone who was never renowned as a road sprinter, I feel
the Ksyriums are no handicap, despite the low profile rim and low spoke
count (20 in the rear).


Why do you do THAT? *Low spoke count and low rim profile don't like
each other!


Quality spoke assemblies don't need exceesive spoke counts. More
consider that 28,32 and 36 spoke assemblies are high spoke counts
which can make up for a less than perfect wheel build yet still be
ridden hard.

There is also some radial stiffness discussion here;


*http://www.sheldonbrown.com/rinard/wheel/grignon.htm

That doesn't sound like a good ruling. *If this is a bicycle event
then competitors should use comparable equipment, which Moser did not.



Yawn.
--
Jobst Brandt


  #129  
Old January 5th 11, 11:10 PM posted to rec.bicycles.tech
[email protected][_2_]
external usenet poster
 
Posts: 1,594
Default Tips on carbon fiber WSD bikes?

On Jan 5, 2:45*pm, Duane Hbert wrote:
On 1/5/2011 4:35 PM, wrote:



Duane Hbert wrote:


I'm looking to replace my old road bike with a carbon fiber model.
My criteria a women's specific design, comfy for all day
riding, smooth riding, light weight, Shimano 105 components, and
preferably with three chainwheels.


Via the web, I've checked out the specs and reviews for following
bikes: Cannondale (Synapse Fem 5), Felt (ZW5), Giant (Avail
Advanced 2), Trek (Madrone 3.1WSD), or Specialized (Ruby Elite
Apex). *I was hoping y'all might have some insights into these
bikes so that I could minimize driving all over the state (there
are no local dealers for most of these) to do the final fit
check-out and test ride. *I don't know how comfort is specified on
a web page.


So here goes. *Assuming equally good fit and tire size/psi - Do
any of these bikes stand out as more smooth riding? *Do any of
these bikes stand out as more comfy for all day long cruising?
Does anyone have any idea how the weights compare for the same
size bike? *Thanks for any help trying to trim down my list of
potential bikes.


NO! *The comfort of a bicycle resides in its wheelbase and tires;
frames and wheels having practically no perceptible elasticity.
Therefore, test ride the bike and see if it fits your body: bars,
pedals, and saddle. *You can't ask for more. *If you chose a
suspension bicycle, you'll get speed instabilities that you won't
like. *Get large enough tires 28-30mm cross section and brakes that
you like. *That's where it's at!


Are you saying that all other things being equal, a bike with a CF
frame is not more comfortable than an aluminum frame? *That a steel
frame is not more comfortable than an aluminum frame? *Or am I
misunderstanding you?


I think what I wrote is unambiguous enough to not be misinterpreted.
You might review the FAQ on what holds the rim off the ground:


What's ambiguous is that you're saying that frames have practically no
elasticity but what about their ability to absorb vibration? *We're
talking about what makes bikes more comfortable. My CF bike seems to
absorb the road vibration better than my last aluminum bike.



the point that some people make is that comfort does not depend on
material but in angles, tires, geometry, etc. In other words, an al
bike with a 71 degree seat angle and a 45 cm chainstay length with 25c
tires inflated to 80psi will be more comfortable than a tight racing
CF frame with 23C tires pumped to 120psi.

Yet, what if i like a tight racing geometry frame and i want to pump
tires to 120psi? In that case, in my experience, as in yours, CF, is
more comfortable than Al.

Im not talking about the old Alan or Vitus frames. I am talking about
the modern Kinesis, Easton (and other brands) oversized al frames
that sell nowadays.

I didn't believe the hype about harsh al frames. So, i bought an al
frame, move all my components from a KHS steel frame (very similar
geometry) and tried the al frame. Boy, keeping everything the same
except for the frame, i was in for a big surprised. There wasn't just
a difference. It was significant. I stopped going down this particular
bumpy road for fear of undoing a fixed bridge in my mouth that
resulted from a bike accident in 1995. On that frame, every little
road bump was felt on every bone.

I kept that frame for a few months before disposing it in ebay and
moving the components to a ti frame that I had. Rattling and bouncing
quickly disappeared and once I lost fear of going down bumpy road I
returned to it and realized that it wasn't that bumpy.

Note that I am not particularly sensitive to the way bikes feel. I
don't claim to notice major differences between tire bead, thickness
weight, etc. Nor do i claim to notice differences between wheels rims,
spokes and such. I don't give a F__ck about weight. My road bike with
stuff weighs about 30lbs. I ride regularly with roadies on $3000 plus
bikes and keep up no problem (except for hills). In fact I owe and
ride very inecpesnive bikes.

But, but, but.... Aluminum is just another story. i noticed a
huuuugeee difference. In fact, It almost made me stop enjoying cycling
for a while, although i've been riding for 25 years and love it.

Do i have scientific evidence that al sucks. No. It is just IMHO.
  #130  
Old January 5th 11, 11:36 PM posted to rec.bicycles.tech
James[_8_]
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Posts: 6,153
Default Tips on carbon fiber WSD bikes?

wrote:
On Jan 5, 2:45 pm, Duane Hbert wrote:
On 1/5/2011 4:35 PM, wrote:



Duane Hbert wrote:
I'm looking to replace my old road bike with a carbon fiber model.
My criteria a women's specific design, comfy for all day
riding, smooth riding, light weight, Shimano 105 components, and
preferably with three chainwheels.
Via the web, I've checked out the specs and reviews for following
bikes: Cannondale (Synapse Fem 5), Felt (ZW5), Giant (Avail
Advanced 2), Trek (Madrone 3.1WSD), or Specialized (Ruby Elite
Apex). I was hoping y'all might have some insights into these
bikes so that I could minimize driving all over the state (there
are no local dealers for most of these) to do the final fit
check-out and test ride. I don't know how comfort is specified on
a web page.
So here goes. Assuming equally good fit and tire size/psi - Do
any of these bikes stand out as more smooth riding? Do any of
these bikes stand out as more comfy for all day long cruising?
Does anyone have any idea how the weights compare for the same
size bike? Thanks for any help trying to trim down my list of
potential bikes.
NO! The comfort of a bicycle resides in its wheelbase and tires;
frames and wheels having practically no perceptible elasticity.
Therefore, test ride the bike and see if it fits your body: bars,
pedals, and saddle. You can't ask for more. If you chose a
suspension bicycle, you'll get speed instabilities that you won't
like. Get large enough tires 28-30mm cross section and brakes that
you like. That's where it's at!
Are you saying that all other things being equal, a bike with a CF
frame is not more comfortable than an aluminum frame? That a steel
frame is not more comfortable than an aluminum frame? Or am I
misunderstanding you?
I think what I wrote is unambiguous enough to not be misinterpreted.
You might review the FAQ on what holds the rim off the ground:

What's ambiguous is that you're saying that frames have practically no
elasticity but what about their ability to absorb vibration? We're
talking about what makes bikes more comfortable. My CF bike seems to
absorb the road vibration better than my last aluminum bike.



the point that some people make is that comfort does not depend on
material but in angles, tires, geometry, etc. In other words, an al
bike with a 71 degree seat angle and a 45 cm chainstay length with 25c
tires inflated to 80psi will be more comfortable than a tight racing
CF frame with 23C tires pumped to 120psi.

Yet, what if i like a tight racing geometry frame and i want to pump
tires to 120psi? In that case, in my experience, as in yours, CF, is
more comfortable than Al.

Im not talking about the old Alan or Vitus frames. I am talking about
the modern Kinesis, Easton (and other brands) oversized al frames
that sell nowadays.

I didn't believe the hype about harsh al frames. So, i bought an al
frame, move all my components from a KHS steel frame (very similar
geometry) and tried the al frame. Boy, keeping everything the same
except for the frame, i was in for a big surprised. There wasn't just
a difference. It was significant. I stopped going down this particular
bumpy road for fear of undoing a fixed bridge in my mouth that
resulted from a bike accident in 1995. On that frame, every little
road bump was felt on every bone.

I kept that frame for a few months before disposing it in ebay and
moving the components to a ti frame that I had. Rattling and bouncing
quickly disappeared and once I lost fear of going down bumpy road I
returned to it and realized that it wasn't that bumpy.

Note that I am not particularly sensitive to the way bikes feel. I
don't claim to notice major differences between tire bead, thickness
weight, etc. Nor do i claim to notice differences between wheels rims,
spokes and such. I don't give a F__ck about weight. My road bike with
stuff weighs about 30lbs. I ride regularly with roadies on $3000 plus
bikes and keep up no problem (except for hills). In fact I owe and
ride very inecpesnive bikes.

But, but, but.... Aluminum is just another story. i noticed a
huuuugeee difference. In fact, It almost made me stop enjoying cycling
for a while, although i've been riding for 25 years and love it.

Do i have scientific evidence that al sucks. No. It is just IMHO.


Hence why Al frame manufacturers went to CF seat stays, etc. on an Al
main triangle.

JS.
 




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