Wheel building questions
big Pete
Hi all,
I have some questions about wheel building. I want to build my back
wheel myself. Cross 3 pattern 14 gauge stainless steal spokes. I
finally got my hub and caste that is compatible with my suntour
component set. I have dishing questions. I know the spoke length are
different on the drive side and non drive side and that dose help with
the dishing, but without a dish stick how do I know I got the dishing
correct? Is it possible to build a dish stick? If so how? I use my bike
as the truing stand this trick has work well for me for many years ...
but it was only used to true a wheels that have been already built. My
wheel building experience thus far is that I have swapped hubs out of
my mtb bike (i.e. replaced my low level hub with a nice higher end hub)
These hubs had the same dimension so I did not have to get new spokes
and calculate spoke length. How do I calculate what length spokes I
need? I saw some calculators on the web but I am interested in
mathematical formula. I have read Brown's page on wheel building.
Thank you all
Pete
--
big Pete
Mike Borean
yielded from the web and Sheldon Brown's book. Before I even attempted I
purchased a park tools truing stand which will take care of the dish as it
centers the rim on the hub as well as telling you the "hop". My LBS looked
at the wheels and was impressed (maybe he was being polite as I am a good
customer). I wouldn't mess with the formulas as a rookie. The spoke length
calculators on the web worked great. Cannot remember which calculator I
used as I downloaded a few and they all gave me the same results.
I found wheel building much easier and enjoyable than I thought it would be.
I also found out that I didn't really save any money, but if I was looking
for effiency, my bikes would have motors on them.
Good luck.
Mike Borean
"big Pete" <big.Pet...@no-mx.forums.cyclingforums.com> wrote in message
news:big.Pet...@no-mx.forums.cyclingforums.com...
Art M
using the brakes for lateral adjustments and a straight edge along the seat
stays for roundness (no tire on rim). Amount of dish is irrelevant. The rim
just has to be in the center and that can be checked by flipping the wheel
over and checking that rim is in the same place. The problem with that is in
getting the brakes centered. If the rim is off center that makes adjusting
the breaks so that they are centered difficult. They are centered when the
same spot on the rim is as close to one break pad as it is to the other when
the wheel is flipped.
As to spoke length measurement stick with the calculators. The formula isn't
a big deal (mostly geometry with an adjustment for spoke stretch), but you
would have to make all kinds of precise measurements of flange distance from
center of hub, spoke hole distance from center, etc. Most of the calculators
have extensive databases that make measurements unnecessary.
Check out http://www.sheldonbrown.com/rinard/spocalc.htm
It's an excel spreadsheet so you should be able to inspect the formulas.
--Art
"big Pete" <big.Pet...@no-mx.forums.cyclingforums.com> wrote in message
news:big.Pet...@no-mx.forums.cyclingforums.com...
>
m-gineering
but without a dish stick how do I know I got the dishing
> correct? Is it possible to build a dish stick? If so how?
If you're on the road I would recommend to go to a cafe and buy two or
three beers. After emptying these rest your wheel with the rim on the
glasses and eyeball the distance between axlenut and ashtray or
whatever. Flip the wheel over as with a regular dish stick.
--
---
Marten
Alex Rodriguez
big.Pet...@no-mx.forums.cyclingforums.com says...
>Hi all,
>I have some questions about wheel building. I want to build my back
>wheel myself. Cross 3 pattern 14 gauge stainless steal spokes. I
>finally got my hub and caste that is compatible with my suntour
>component set. I have dishing questions. I know the spoke length are
>different on the drive side and non drive side and that dose help with
>the dishing, but without a dish stick how do I know I got the dishing
>correct?
Very easy. You flip the wheel in the truing stand. When it stays in the
same position when you flip it, it is centered. I would also recommend
using double butted spokes instead of straight gauge.
>Is it possible to build a dish stick? If so how?
Yes it is possible. I'm sure a google search will turn up multiple plans.
>I use my bike
>as the truing stand this trick has work well for me for many years ...
>but it was only used to true a wheels that have been already built. My
>wheel building experience thus far is that I have swapped hubs out of
>my mtb bike (i.e. replaced my low level hub with a nice higher end hub)
>These hubs had the same dimension so I did not have to get new spokes
>and calculate spoke length. How do I calculate what length spokes I
>need? I saw some calculators on the web but I am interested in
>mathematical formula. I have read Brown's page on wheel building.
I would recommnend buying, or borrowing, a copy of 'The Bicycle Wheel' by
Jobst Brandt. It has everything you need to know to build up a good strong
wheel.
-------------
Alex
John Everett
<big.Pet...@no-mx.forums.cyclingforums.com> wrote:
>
>Hi all,
>
>I have some questions about wheel building. I want to build my back
>wheel myself. Cross 3 pattern 14 gauge stainless steal spokes. I
>finally got my hub and caste that is compatible with my suntour
>component set. I have dishing questions. I know the spoke length are
>different on the drive side and non drive side and that dose help with
>the dishing, but without a dish stick how do I know I got the dishing
>correct?
From a posting I made to r.b.t on 1997/12/30:
"At risk of drawing flames, let me suggest that a flat surface and a
machinists rule (or probably just a regular ruler) does an adequate
job as a dishing tool. Put the wheel (skewer removed) on the flat
surface with one section of the rim in contact with the surface.
Measure the height of the rim 180° opposite, then flip it over and
remeasure. If the measurements are equal (assuming an equal amount of
axle extends beyond the locknut on each side, and the rim is running
true), the wheel is properly dished.
jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3
David L. Johnson
>
> Hi all,
>
> I have some questions about wheel building. I want to build my back wheel
> myself. Cross 3 pattern 14 gauge stainless steal spokes.
You probably have them already, but if not I recommend butted spokes.
They make a more reliable wheel.
> I finally got my
> hub and caste that is compatible with my suntour component set. I have
> dishing questions. I know the spoke length are different on the drive
> side and non drive side and that dose help with the dishing,
Only about 1mm, not significant.
> but without
> a dish stick how do I know I got the dishing correct? Is it possible to
> build a dish stick? If so how?
Easy. Get a piece of metal stock long enough to span the wheel. At each
end, drill a hole and install a 3" bolt, so that the ends touch the
braking flats of the rim on opposite sides. Get one more bolt, and use
wing-nuts to allow you to move it easily, drill a hole in the middle and
attach it.
Here is ascii-art indicating what it should look like:
| |
|___________________________|________________________________|
|
^
Hope that gives the idea. The point is that the distance from the end of
the axle lock-nut to the rim should be the same on either side. Place
this against one side, adjust the middle bolt to just scrape the axle
lock-nut when the other two are resting on the rim, then flip it around
and see if it fits the same way on the other side. If not, tighten one
side's spokes 1/4 turn and try again. Tighten the side where the axle
sticks out too much. Use the locknuts, not the end of the axle, since
they are not always centered.
Of course, you could just stick the wheel on the bike, check the distance
to the brake blocks, then flip the wheel around and re-check, but a gauge
is more accurate.
> length. How do I calculate what length spokes I need? I saw some
> calculators on the web but I am interested in mathematical formula. I
> have read Brown's page on wheel building.
I'd imagine the formulas are in Jobst's book. But the on-line calculators
are pretty good. You can get one that is a spreadsheet, with dimension
data for various brands and all, and it will have the formulas programmed
into it.
--
David L. Johnson
__o | "Business!" cried the Ghost. "Mankind was my business. The
_`\(,_ | common welfare was my business; charity, mercy, forbearance,
(_)/ (_) | and benevolence, were, all, my business. The dealings of my
trade were but a drop of water in the comprehensive ocean of my
business!" --Dickens, "A Christmas Carol"
Zog The Undeniable
> Is it possible to build a dish stick? If so how?
Easy. Get a flat piece of material, about wheel diameter length and a
few inches across, with a known flat surface on one side. A piece of
old Formica kitchen cabinet is good.
Using a coping saw, sculpt away enough of the material on the "flat"
side to clear the spokes. In the middle of the curve you've created,
screw in a big woodscrew (so the head is inside the curve).
To check dish simply put the flat edge on the rim and adjust the screw
until it rests on the locknut. Flip the wheel over and check the
measurement is the same on the other side.
carl...@comcast.net
<david....@lehigh.edu> wrote:
>On Tue, 12 Oct 2004 01:49:03 +1000, big Pete wrote:
>
[snip]
>> How do I calculate what length spokes I need? I saw some
>> calculators on the web but I am interested in mathematical formula. I
>> have read Brown's page on wheel building.
>
>I'd imagine the formulas are in Jobst's book. But the on-line calculators
>are pretty good. You can get one that is a spreadsheet, with dimension
>data for various brands and all, and it will have the formulas programmed
>into it.
Dear Pete and Dave,
Yes, Jobst Brandt's "Equations" section at the end of "The
Bicycle Wheel" has a page devoted to an equation for
calculating spoke length.
Carl Fogel
daveornee
big Pete Wrote:
> I am a big guy (245 pounds last time I checked) will butted spokes make
> that big of a strength difference in the wheel? I did not buy the rim
> and spokes yet. I am thinking of a Sun double walled rim with eyelets
> that I can get for a good price. And the spokes are 14 gauge stainless
> steal (non butted) as stated in the my first post. I will Also try to
> make a dish stick. Looks like I am able to make it from the suggestions
> you guys have given me.
>
> Thank you all
>
> Pete
DT or Sapim 14/15 double butted spokes will make the wheel more
durable, but not as stiff.
Suggested Reading: "the Bicycle Wheel" by Jobst Brandt. The book is
available in some library systems as well as for purchase.
--
daveornee
carl...@comcast.net
<big.Pet...@no-mx.forums.cyclingforums.com> wrote:
>
>David L. Johnson Wrote:
>>
>> You probably have them already, but if not I recommend butted spokes.
>> They make a more reliable wheel.
>>
>
>I am a big guy (245 pounds last time I checked) will butted spokes make
>that big of a strength difference in the wheel? I did not buy the rim
>and spokes yet. I am thinking of a Sun double walled rim with eyelets
>that I can get for a good price. And the spokes are 14 gauge stainless
>steal (non butted) as stated in the my first post. I will Also try to
>make a dish stick. Looks like I am able to make it from the suggestions
>you guys have given me.
>
>Thank you all
>
>Pete
Dear Pete,
Both thick 14 gauge spokes and thin butted spokes with 14
gauge ends and a 15 gauge middle are more than strong enough
to bear the loads--they break at the ends, not in the
middle.
Double-butted spokes keep the ends thick to try to reduce
such breaks.
Their advantage is that, being thinner for most of their
length, they stretch more and therefore are less likely to
lose all tension (a bad thing) as they roll under the hub.
When the rim flattens ever so slightly against the pavement,
the spoke above it loses tension. A thick straight spoke
didn't stretch as far as a thin-center-section spoke, so the
thick spoke loses all tension and rattles, going out of true
and breaking more often and while the thin spoke can
contract that much and still have tension, which makes it
likely to last longer.
Think of them as rubber bands at the same tension, neither
of which is going to snap in the middle, but neither of
which we want to go slack. The thinner rubber band enjoys a
greater range of motion.
Carl Fogel
big Pete
Dear Carl,
You are going to have to enlighten me a bit more. I think I agree with
your analogy. OK so the thinner band has a better range of motion. But
that would imply that they will ware out faster because of the bigger
range of motion they are going though.
--
big Pete
John Everett
If you're interested in the actual formula, I have a small Excel .xls
file that calculates spoke length. It's already filled in with
dimensions for a couple of wheels I built some time ago, but if you
plug in your dimensions in the appropriate cells you'll get results in
the obvious cells. Open those cells to see the formula used.
Email if you want the .xls file and I'll send it along as an
attachment to a return email.
carl...@comcast.net
<big.Pet...@no-mx.forums.cyclingforums.com> wrote:
Dear Pete,
You raise a good point, but the long thinner middle section
of spokes doing the stretching simply doesn't wear out.
That is, spokes don't break in the middle. They fatigue,
crack, and fail at the elbow about nine times out of ten.
The tenth spoke one breaks at the nipple. That's why the
spokes are left thick (double-butted) at each end.
Even a thin mid-section stainless steel spoke is so strong
in tension that it isn't going to fail due to the normal
stress cycle of losing and regaining tension as it rolls
under the axle.
As others have suggested in this thread, this is roughly
what Jobst Brandt points out in "The Bicycle Wheel" when he
recommends double-butted spokes. Paradoxically, a thinner
mid-section spoke produces a more reliable wheel, not
because it is stronger than a thicker spoke (it isn't), but
because it is more than strong enough and its increased
elasticity lets it function better at what spokes need to
do, which is to maintain tension throughout the load range
without going slack.
The metallurgical side of this is that ferrous metals
(steels) have the charming characteristic of being able to
cycle indefinitely if the stress is low enough--they just
won't fatigue and break. (The elbows and nipples break
because stress is concentrated there and encouraged by
various details like the bending, the threading, and so
forth.) So the engineers can design a steel structure to
last forever in terms of stress cycles if the stress is kept
low enough.
Non-ferrous metals like aluminum, titanium, and magnesium do
not share this ruggedness. Given enough stress cycles, they
fatigue, no matter how low the stress is. The engineers have
to design non-ferrous structures to reduce the amount of
stress in each cycle, reduce the cycles, or both--and still
they can calculate when non-ferrous things should bust.
Some theory holds that steels eventually do fatigue even at
low stress cycling, but so much later that it's indefinite
for practical purposes. But no theory that I know of
predicts that a double-butted spoke will wear out in the
middle--it will break at the elbow or nipple, but not as
soon as a straight, thick spoke that is more prone to losing
all tension if it rolls under a heavily loaded axle.
For heavier loads, the usual solution is more spokes, not
thicker spokes--36 spokes might increase to 48 spokes for
many tandems and for truly heavy riders like Chalo Colina,
who has about 135 pounds on lightweights like you and 185
pounds on delicate creatures like me.
Carl Fogel
big Pete
Dear Carl,
Thank you for the enlighten. I will look into double-butted spokes. I
have not yet had too many problems with 36 spokes on a wheel ... The
only spokes that brake on me are the ones from the wheel I got from the
garbage (this wheel is on my pos commuter). I am also looking for the
book you guys mentioned to me, right now though my library system. Is
this book the "wheel builders bible"? I have never had a wheel with
double-butted spokes does it make a difference in feel?
Pete
--
big Pete
Alex Rodriguez
big.Pet...@no-mx.forums.cyclingforums.com says...
>I am also looking for the
>book you guys mentioned to me, right now though my library system. Is
>this book the "wheel builders bible"?
No.
>I have never had a wheel with
>double-butted spokes does it make a difference in feel?
No.
------------
Alex
big Pete
Hi all,
Thank you for all the information. I have one more stupid question.
What is the right side of the wheel? I am assuming this would be the
drive side. (i.e. I am siting on my bike and looking down. i.e. I am
not looking at the bike face on; in that both the bike, wheel, and me
are facing the same direction.)
Pete
--
big Pete
Sheldon Brown
Sure, what else could it be? It's the side with the right pedal (which
is marked with a little "R".
Call it "starboard" if you're nautical.
Sheldon "Learned This In Kindergarten" Brown
+--------------------------------------------+
| Silence is not always a sign of wisdom |
| but babbling is ever a mark of folly. |
| -- Benjamin Franklin |
+--------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
Per Elmsäter
> Sheldon Brown <capt...@sheldonbrown.com> wrote, in part, in message
>>
>> Call it "starboard" if you're nautical.
>>
>
> App
If you don't figure that out in a hurry, you're gonna be locked in irons
real soon ;)
--
Perre
I gave up on SPAM and redirected it to hotmail instead.
carl...@comcast.net
<big.Pet...@no-mx.forums.cyclingforums.com> wrote:
Dear Pete,
Interlibrary loan should be able to get a copy of Jobst
Brandt's "The Bicycle Wheel." If possible, specify the third
edition. Here on rec.bicycles.tech, it's often referred to
as the bible--and like any bible, it has passages that
inflame controversy.
For example, I remain agnostic about the spoke-squeezing
stress-relief theory that's supposed to make spokes
immortal, but even if turns out to be myth and lore, I can't
see how it can hurt anything.
Online, you can browse Sheldon Brown's detailed
wheel-building page here:
http://www.sheldonbrown.com/wheelbuild.html
It has colored diagrams, handy links to many terms, and a
reference to Jobst's book--with a link to let you buy it
online from Sheldon in Massachusetts, who can probably use
some cheering up after the Yankees trounced Boston last
night.
As for any difference in feel between butted and unbutted
spokes, I'd be astonished if anyone claimed to be able to
tell the difference. While the increased elasticity of the
thinner-middle-section spoke helps keep tension on the spoke
as it rolls under the hub, the actual amount of stretching
is tiny. The rubber of the tire deforms far more than the
spoke changes length. When you look at diagrams showing how
the rim flattens at the contact patch, there's usually a
comment that the amount of distortion is greatly
exaggerated--otherwise, you couldn't see the difference.)
However, there might be one situation in which you could
tell the difference in feel while riding double-butted
spokes. When a wheel hits something hard enough to cause a
spoke to lose all tension and go slack, there might be a
faint but unpleasant rattle and then a click as the wheel
continues rolling and tension is regained. (I've never
noticed this, but vaguely recall people mentioning it here.)
You'd get less of that with double-butted spokes. Otherwise,
the increased stretchiness would be undetectable by a rider.
Carl Fogel
jobst....@stanfordalumni.org
It's not the side where your right arm is when sitting on the handlebars
pedaling backwards, nor the side where the center stripe of the road
is (in the USA) nor where you extend your left arm to make a left turn.
Jobst Brandt
jobst....@stanfordalumni.org
carl...@comcast.net
<nos...@example.net> wrote:
>need more precision here carl. if by "ferrous metals" you mean mild
>steel, then yes, it has an endurance limit below which it won't fatigue.
> but if by "ferrous metals" you're including stainless steels, then
>that's an incorrect statement. endurance limits are a function of
>carbon content, and carbon is usually kept to a minimum in most
>stainless steels to prevent harmful formation of chromium carbide.
>
>>
>> Non-ferrous metals like aluminum, titanium, and magnesium do
>> not share this ruggedness. Given enough stress cycles, they
>> fatigue, no matter how low the stress is. The engineers have
>> to design non-ferrous structures to reduce the amount of
>> stress in each cycle, reduce the cycles, or both--and still
>> they can calculate when non-ferrous things should bust.
>
>see above.
>
>>
>> Some theory holds that steels eventually do fatigue even at
>> low stress cycling, but so much later that it's indefinite
>> for practical purposes. But no theory that I know of
>> predicts that a double-butted spoke will wear out in the
>> middle--it will break at the elbow or nipple, but not as
>> soon as a straight, thick spoke that is more prone to losing
>> all tension if it rolls under a heavily loaded axle.
>>
>> For heavier loads, the usual solution is more spokes, not
>> thicker spokes--36 spokes might increase to 48 spokes for
>> many tandems and for truly heavy riders like Chalo Colina,
>> who has about 135 pounds on lightweights like you and 185
>> pounds on delicate creatures like me.
>
>i'm down to 200, & i'm still riding 16 spoke wheels to no detriment.
>
>>
>> Carl Fogel
Dear Jim and Pete,
I expect that Jim's correction about the low-carbon
stainless steel used in spokes being more prone to fatigue
than other steels is quite right, since materials are Jim's
field.
But I steel (irresistible) wouldn't worry about the thinner
mid-sections of butted spokes wearing out. Again, for Pete's
sake (again, irresistible), spokes fatigue and break at the
ends, not in the middle.
Carl Fogel
Chalo
> i'm down to 200, & i'm still riding 16 spoke wheels to no detriment.
That depends on what you consider a detriment. Low spoke count wheels
are, at best, no stronger than wheels of equal weight with
conventional spoke counts. They are also more flexible and a lot more
difficult to true and service. They become unrideable from damage
that is tolerable to a conventional wheel.
--All this in exchange for benefits that lie in the range between
unmeasurable and insignificant.
Chalo Colina
carl...@comcast.net
>I'd be surprised if there weren't a difference in feel. A bike wheel's a pretty
>resonant structure and resonances ARE easy to feel. Having said that I'll agree
>that there won't be a discernable difference in deformation under load. But a
>thinner spoke pulled to the same tension as a thicker one will resonate at a
>higher pitch. All of the shock and vibration from the road is transmitted
>through this resonant structure, I can't believe there won't be a difference in
>feel.
>
>Time for someone to buld up some matched wheelsets for testing and test ride
>them with a focus on road buzz and vibration, etc.
>
>Ron
Dear Ron,
I think that the usual problem of claims about "feel" is
hard to overcome. No matter how resonant the structure of
the metal spokes, hub, and rim may be, it's all damped by
the inflated rubber tire.
But you could be right. A faintly similar test would be to
try to tell the difference between hitting a tire while
blindfolded with the same hammer heads mounted on different
rubber-covered shafts--wood, fiberglass, and steel. I know
that carpenters believe in differences between the feel of
such materials, but I don't know about whether they would
claim to feel the difference with a resilient rubber tire on
one end and a rubber grip on the other.
Carl Fogel
John Forrest Tomlinson
<capt...@sheldonbrown.com> wrote:
>big Pete wrote:
>
>> Thank you for all the information. I have one more stupid question.
>> What is the right side of the wheel? I am assuming this would be the
>> drive side. (i.e. I am siting on my bike and looking down. i.e. I am
>> not looking at the bike face on; in that both the bike, wheel, and me
>> are facing the same direction.)
>
>Sure, what else could it be? It's the side with the right pedal (which
>is marked with a little "R".
>
>Call it "starboard" if you're nautical.
>
I call it the leeside when I'm heading uptown, and the windward side
when I return.
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************
jim beam
well, there's one huge advantage of low spoke count wheels - that of
wind resistance. let's ignore the arguments about "makes no difference
to speed" a moment and look at a much more tangible example. i commute
by bike most days by bike across the golden gate bridge to san
francisco. it's almost always subject to significant cross wind on both
the approaches and on the bridge itself. riding a normal 32 spoke
wheelset, my bike is somewhat squirrely when the wind is bad. riding 16
spoke wheels however, the effect of cross winds is substantially less.
my low spoke wheels are shimano r540's and they have much deeper rims
than my ma3 32 spokers, so if rim alone were the factor, the ma3's would
be the less susceptible ride. given the fact that the r540's are
better, it can only be that the lower wind resistance /is/ a result of
lower spoke count, yes? and i'm not talking a little gust of wind here
- i'm talking gnarly stuff that blows the glasses off your face - as has
happened. trust me, in those conditions, you want wheels which you
/don't/ have to wrestle with the whole way home.
carl...@comcast.net
<nos...@example.net> wrote:
>carl...@comcast.net wrote:
><snip>
>>
>> Dear Ron,
>>
>> I think that the usual problem of claims about "feel" is
>> hard to overcome. No matter how resonant the structure of
>> the metal spokes, hub, and rim may be, it's all damped by
>> the inflated rubber tire.
>
>if i flick a highly inflated tire with my finger, and the whole wheel
>rings like a bell, has the shock of that minor impact been all damped by
>the rubber or has it been transmitted to the wheels structure?
>
>>
>> But you could be right. A faintly similar test would be to
>> try to tell the difference between hitting a tire while
>> blindfolded with the same hammer heads mounted on different
>> rubber-covered shafts--wood, fiberglass, and steel. I know
>> that carpenters believe in differences between the feel of
>> such materials, but I don't know about whether they would
>> claim to feel the difference with a resilient rubber tire on
>> one end and a rubber grip on the other.
>>
>> Carl Fogel
Dear Jim,
I instantly assumed that you were insane, began scribbling a
reply that would expose your evil claims as the work of the
devil, and then remembered that I have a bicycle sitting in
the garage--a bicycle that I trust to back me up faithfully
whenever questions are raised.
I flicked a confident fingernail against the rear tire as my
bicycle slept peacefully on its back, wheels in the air. It
produced a dull, satisfying thunk, indicating that Jim Beam
is deluded. I flicked it several more times to confirm that
it was about as bell-like as a rubber ducky.
But then I grew over-confident and flicked my fingernail
against the front tire. Same tire model, same rim, 36
spokes, roughly the same tension, same inflation--and a
faint but undeniably bell-like vibration was painfully
evident.
The traitorous bicycle was rudely flipped right side up and
both tires were mercilessly flicked with a standard
fingernail. I leaned on the handlebars and on the seat. I
rolled it back and forth. But things remained stubbornly the
same. The rear tire sounded like someone kicking a car tire.
The front tire still gave a faint vibration.
Maybe the chain and gear cluster and freehub mechanism
deaden things on the rear wheel? Or the rigid triangle damps
things better than the fork? I checked that the brake pads
weren't binding.
I loosened both quick-releases. Same thing--front rings,
back doesn't.
I pulled the rear wheel out of the rigid frame and free from
the chain and began flicking it cruelly with my fingernail,
trying to make it cry as it stood helpless and alone on the
garage floor. It still emitted nothing more than a dull
thunk.
So maybe the weight of just the gears and freehub is enough
to deaden the vibration?
Or just the damping of a plastic spoke protector?
If you're familiar with violins, you know how tiny and yet
effective a wooden, rubber, or plastic mute is when pressed
against or clipped onto the bridge:
http://www.sharmusic.com/itemdy00Violin.asp?T1=1304+GLD&Cat=
I hope that others will take a few moments and flick their
front and rear tires in the back of the head with a
fingernail--they can't fight back, so you can bully them as
much as you like.
Whether slight differences in such faint vibration can be
noticed while rolling along on the pavement is another
matter, but I want to know why my front wheel aspires to
Stradivarian heights, while my rear wheel seems to have a
cold.
Carl Fogel
dianne_1234
wrote:
>carl...@comcast.net wrote:
><snip>
>>
>> Dear Ron,
>>
>> I think that the usual problem of claims about "feel" is
>> hard to overcome. No matter how resonant the structure of
>> the metal spokes, hub, and rim may be, it's all damped by
>> the inflated rubber tire.
>
>if i flick a highly inflated tire with my finger, and the whole wheel
>rings like a bell, has the shock of that minor impact been all damped by
>the rubber or has it been transmitted to the wheels structure?
Is the wheel suspended in the air, or on the ground with the rider on
the bike?
carl...@comcast.net
Dear Dianne,
Bell-like ringing from fingernail-flicking of tire . . .
My 36-spoke clunker front wheel 700c x 26 with slime tube at
about 120 psi did it with the quick release secured and
unsecured while the bike was upside down; did it again with
the bike right side up and the tire on the ground; yeat and
again with me leaning hard on the handlebars with an
outraged look on my face.
It isn't the chime of the bells that let me find my dogs
amidst the junipers, but it's undeniably a ringing from the
spokes.
My rear wheel refused to do it, even when removed from the
frame. I suspect either the weight of the rear hub mechanism
and gears, or the damping of the plastic spoke protector.
I'm quite indignant about it, which probably amuses Jim Beam
no end.
It being daylight now, I just went out, flipped the Fury
RoadMaster on its back, and began flicking its enormous,
soggy, 60 psi tires with a brutal fingertip. Same thing. The
front wheel rings, the back emits a sullen thud.
Then I tried flicking the spokes--even clearer ringing tones
on the front, and the back began to ring a bit, too. You'd
think that the Fury's massively treaded 2-inch tires would
have enough rubber to mute a tuba, but the stiffness from
inflation and the spoke tension seems to overcome most of
it.
Carl Fogel
jim beam
does it matter? the point is, just like jobst is at pains to point out
about wheels, in a tire you have a tightly tensioned set of casing
cords, which when momentarily relaxed by the flick of a finger, transmit
an impulse of shock to the rest of the wheel.
big Pete
carl...@comcast.net Wrote:
> On Thu, 14 Oct 2004 20:37:47 -0700, jim beam
> <nos...@example.net> wrote:
>
> >carl...@comcast.net wrote:
> ><snip>
> >>
> >> Dear Ron,
> >>
> >> I think that the usual problem of claims about "feel" is
> >> hard to overcome. No matter how resonant the structure of
> >> the metal spokes, hub, and rim may be, it's all damped by
> >> the inflated rubber tire.
> >
> >if i flick a highly inflated tire with my finger, and the whole wheel
> >rings like a bell, has the shock of that minor impact been all damped
> by
> >the rubber or has it been transmitted to the wheels structure?
> >
> >>
Dear Carl and others,
I have tyred this test just now. The same thing happened to me, my back
wheel rang less than the front wheel (I would not say it was a thud ...
it seemed like a long thud (i.e. it had a very slight ring to it)).
This was on my road bike with the bent axle trued to compensate for the
bend (This is the wheel I will be replacing). This wheel has no plastic
guard on it, x 3 strait gage spokes. Why does my front wheel ring more
than my back?
Pete
--
big Pete
carl...@comcast.net
Dear Pete,
Since your rear wheel lacks a plastic spoke guard, the most
likely suspect in the deadening of the rear wheel versus the
front when the tire is flicked with a fingernail is the
extra mass of the gear cluster and the hub mechanism
Carl Fogel
Chalo
>
> well, there's one huge advantage of low spoke count wheels - that of
> wind resistance.
> it's almost always subject to significant cross wind on both
> the approaches and on the bridge itself. riding a normal 32 spoke
> wheelset, my bike is somewhat squirrely when the wind is bad. riding 16
> spoke wheels however, the effect of cross winds is substantially less.
OK, that's an issue I had not considered. The effects of crosswinds
are not noticeable to me, even with 48 spoke wheels. I suppose that
my weight and preferred bike geometry (slack and stable) probably
minimize crosswind-related steering anomalies.
Chalo Colina
David Damerell
>jim beam <nos...@example.net> wrote:
>>it's almost always subject to significant cross wind on both
>>the approaches and on the bridge itself. riding a normal 32 spoke
>>wheelset, my bike is somewhat squirrely when the wind is bad. riding 16
>>spoke wheels however, the effect of cross winds is substantially less.
>OK, that's an issue I had not considered. The effects of crosswinds
>are not noticeable to me, even with 48 spoke wheels.
It's obvious nonsense, too; how do you suppose sock-boy imagines tandem
captains manage, with 48 spoke wheels and an extra rider stuck out the
back?
[Even if it's only the front wheel - and if then, why run a 16 spoke rear
wheel, hmmm? - a bike with front panniers on would be unmanageable if this
idea was correct.]
--
David Damerell <dame...@chiark.greenend.org.uk> Distortion Field!
carl...@comcast.net
<dame...@chiark.greenend.org.uk> wrote:
Dear David,
Perhaps "Dangerous Crosswind" road signs aren't as common in
your neck of the woods?
On this side of the Atlantic, high wind warnings sometimes
close the interstate highway heading south from Pueblo to
New Mexico--usually after a few trucks blow over.
Up on bridges like the Golden Gate, the winds are usually
worse.
And there's always this example of a what a wind can do:
http://www.nwrain.com/~newtsuit/recoveries/narrows/gg.htm
That's just a 35 to 45 mph crosswind, not terribly unusual
for that bridge and area.
Carl Fogel
Chalo
>
> Chalo <chump...@hotmail.com> wrote:
>
> >jim beam <nos...@example.net> wrote:
> >>
> >>riding 16
> >>spoke wheels however, the effect of cross winds is substantially less.
> >
> >OK, that's an issue I had not considered. The effects of crosswinds
> >are not noticeable to me, even with 48 spoke wheels.
>
> It's obvious nonsense, too; how do you suppose sock-boy imagines tandem
> captains manage, with 48 spoke wheels and an extra rider stuck out the
> back?
To extend "jim beam" the benefit of the doubt, I'll point out that a
tandem captain's situation is more like my own, with a heavily loaded
front wheel that is unlikely to be pushed around by wind due to its
sizeable contact patch. It's obvious if you ride one that a tandem
requires more force at the bars than a single bike, especially a
twitchy single.
> [Even if it's only the front wheel - and if then, why run a 16 spoke rear
> wheel, hmmm? - a bike with front panniers on would be unmanageable if this
> idea was correct.]
A bike with empty and lightweight front panniers would likely be
unmanageable in heavy crosswinds if jim beam's assertion is correct,
and for all I know it might be. A bike with loaded front panniers
would probably have enough inertia in its front end to render a
comparison inconclusive.
Since I have no applicable experience by which to judge jim beam's
assertion, I am inclined to take him at his word, in the absence of
other relevant evidence. I have insufficient data to just assume he's
wrong.
If he's correct, I still don't think that makes a compelling argument
for the general use of 16-spoke wheels. But at least there would be
some functional quality for which he has traded off all the advantages
of conventional wheels.
Chalo Colina
jobst....@stanfordalumni.org
>>>> Riding a normal 32 spoke wheelset, my bike is somewhat squirrely
>>>> when the wind is bad. Riding 16 spoke wheels however, the effect
>>>> of cross winds is substantially less.
>>> OK, that's an issue I had not considered. The effects of
>>> crosswinds are not noticeable to me, even with 48 spoke wheels.
>> It's obvious nonsense, too; how do you suppose sock-boy imagines
>> tandem captains manage, with 48 spoke wheels and an extra rider
>> stuck out the back?
> To extend "jim beam" the benefit of the doubt, I'll point out that a
> tandem captain's situation is more like my own, with a heavily
> loaded front wheel that is unlikely to be pushed around by wind due
> to its sizeable contact patch. It's obvious if you ride one that a
> tandem requires more force at the bars than a single bike,
> especially a twitchy single.
Crosswinds do not make wheels skid sideways, but rather they induce
steering movements while causing the rider to lean sideways as if
cornering. In gusty winds this makes riding a reasonably straight
path impossible and can blow the rider into the adjacent lane (or off
the road). It's a lot like riding next to someone pushing on one's
shoulder while shoving the handlebar forward. Both of these effects
have little to do with number of spokes, mainly arising from the
longitudinal cross section of the wheel and that of the rider.
>> [Even if it's only the front wheel - and if then, why run a 16
>> spoke rear wheel, hmmm? - a bike with front panniers on would be
>> unmanageable if this idea was correct.]
> A bike with empty and lightweight front panniers would likely be
> unmanageable in heavy crosswinds if jim beam's assertion is correct,
> and for all I know it might be. A bike with loaded front panniers
> would probably have enough inertia in its front end to render a
> comparison inconclusive.
Weight on the wheel has no effect. It is mainly the effect of wind
steering the front end. Rear wheels have no effect on steering
although total cross section of bicycle and rider exposed to a lateral
wind affects lean. One effect steers the bicycle off course and the
other requires the rider lean into the wind or fall over.
> Since I have no applicable experience by which to judge jim beam's
> assertion, I am inclined to take him at his word, in the absence of
> other relevant evidence. I have insufficient data to just assume he's
> wrong.
The claim is probably less accurate that it may first appear because
rim depth is the principal contributor to side wind sensitivity. Disc
wheels don't work at all in cross winds of any significant for this
reason. Sixteen spoke wheels generally have deeper rim cross sections
than thirty two spoke wheels and produce a greater steering effect.
Spoke count is insignificant because the steering effect in a 15mph
wind is like the spoke drag effect riding forward at 15-20mph in still
air, where I'm sure you can't detect the difference between 16 and 32
spokes without a stop watch.
> If he's correct, I still don't think that makes a compelling argument
> for the general use of 16-spoke wheels. But at least there would be
> some functional quality for which he has traded off all the advantages
> of conventional wheels.
I see no advantage other than TT racing in still or nearly still air.
Jobst Brandt
jobst....@stanfordalumni.org
jim beam
> Chalo Colina writes:
>
>
>>>>>Riding a normal 32 spoke wheelset, my bike is somewhat squirrely
>>>>>when the wind is bad. Riding 16 spoke wheels however, the effect
>>>>>of cross winds is substantially less.
>
>
>>>>OK, that's an issue I had not considered. The effects of
>>>>crosswinds are not noticeable to me, even with 48 spoke wheels.
>
>
>>>It's obvious nonsense, too; how do you suppose sock-boy imagines
>>>tandem captains manage, with 48 spoke wheels and an extra rider
>>>stuck out the back?
>
>
>>To extend "jim beam" the benefit of the doubt, I'll point out that a
>>tandem captain's situation is more like my own, with a heavily
>>loaded front wheel that is unlikely to be pushed around by wind due
>>to its sizeable contact patch. It's obvious if you ride one that a
>>tandem requires more force at the bars than a single bike,
>>especially a twitchy single.
>
>
> Crosswinds do not make wheels skid sideways
did anyone say "skid"? you're twisting facts.
>, but rather they induce
> steering movements while causing the rider to lean sideways as if
> cornering. In gusty winds this makes riding a reasonably straight
> path impossible and can blow the rider into the adjacent lane (or off
> the road). It's a lot like riding next to someone pushing on one's
> shoulder while shoving the handlebar forward. Both of these effects
> have little to do with number of spokes, mainly arising from the
> longitudinal cross section of the wheel and that of the rider.
didn't you read my description and dicussion of the effect of rim
section? have you ever ridden this kind of wheel? you may be
interested to know, i read your dismissal of this kind of wheel before i
rode one and was "surprised" to find it's behavior contrary to your
expectations. and i say "expectations" because, as usual, you're
holding forth without direct personal experience - just like your
"experience absent" contention that carbon forks don't attenuate
vibration transmission - something that composites are know for.
just ride one of these wheels jobst.
>
>
>>If he's correct, I still don't think that makes a compelling argument
>>for the general use of 16-spoke wheels. But at least there would be
>>some functional quality for which he has traded off all the advantages
>>of conventional wheels.
>
>
> I see no advantage other than TT racing in still or nearly still air.
sure - cross winds & head winds are never encountered outside of palo
alto, so we can can all go back to 70's technology!
1973 tour de france average speed: 33.407kph
2001 tour de france average speed: 40.070kph
>
> Jobst Brandt
> jobst....@stanfordalumni.org
Tim McNamara
> sure - cross winds & head winds are never encountered outside of
> palo alto, so we can can all go back to 70's technology!
>
> 1973 tour de france average speed: 33.407kph 2001 tour de france
> average speed: 40.070kph
jim, don't make yourself out to be an idiot if you don't have to.
Most of the time the wheels are not all that different from 1973; you
forgot to factor in EPO and other performance enhancers that weren't
available in 1973; road surfaces for the Tour are much better now than
they were in 1973; and you fail to mention the many races with record
speeds set 10-15-20-30 years ago that still stand or would at least be
very competitive with 2004 speeds. Climbers are faster thanks to
chemistry, and TTs are faster thanks to technology- in the latter
case, the wheels might be slightly beneficial but it's rider
aerodynamics that's made the most difference.
carl...@comcast.net
<tim...@bitstream.net> wrote:
>jim beam <nos...@example.net> writes:
>
>> sure - cross winds & head winds are never encountered outside of
>> palo alto, so we can can all go back to 70's technology!
>>
>> 1973 tour de france average speed: 33.407kph 2001 tour de france
>> average speed: 40.070kph
>
>jim, don't make yourself out to be an idiot if you don't have to.
>Most of the time the wheels are not all that different from 1973.
[snip]
Dear Tim,
Are the typical 2004 Tour wheels really "not all that
different" from the typical 1973 wheels?
Isn't the spoke count reduced?
I'm not arguing that you were wrong about all the other
things that improved times in the Tour, nor that reducing
spoke count will or won't help in crosswinds.
But my impression is that modern low-spoke-count wheels are
different enough that just tensioning them requires a
different approach involving unloading the section of the
rim around the spoke in order to turn the nipple.
If I'm right, I still don't think that you're an idiot--just
a little excited.
If I'm wrong, I'll end up as a slightly smarter idiot, but
still riding 36-spoke wheels
Browsing through my god-fearing spreadsheet (miles, not
kilometers), I see a general rising trend in average Tour
speed, but 1973 was an unusually slow year--slower than any
previous year back to 1954. Who was riding, what the weather
was like, and the route chosen will all account for a lot of
the differences.
The post-war dates, distances, and average speed for the
winner follow below. (No pre-war Tour winner reached an
average of 20 mph.)
Cheers,
Carl Fogel
year winner miles mph
1947 robic 2900 19.57
1948 bartali 3076 20.90
1949 coppi 3005 20.08
1950 kubler 2984 20.50
1951 koblet 2931 20.59
1952 coppi 3061 20.15
1953 bobet 2798 21.62
1954 bobet 2910 20.77
1955 bobet 2809 21.53
1956 walkoiak 2811 22.67
1957 anquetil 2929 21.57
1958 gaul 2699 23.07
1959 bahamontes 2744 22.17
1960 nencini 2608 23.26
1961 anquetil 2748 22.52
1962 anquetil 2671 23.32
1963 anquetil 2631 23.18
1964 anquetil 2815 22.14
1965 gimondi 2618 22.43
1966 aimar 2706 23.01
1967 pingeon 2988 21.82
1968 janssen 2808 20.98
1969 merckx 2573 22.13
1970 merckx 2659 22.24
1971 merckx 2255 23.31
1972 merckx 2404 22.20
1973 ocana 2556 20.88
1974 merckx 2561 22.03
1975 thevenet 2500 21.82
1976 van impe 2511 21.57
1977 thevenet 2560 22.14
1978 hinault 2443 22.55
1979 hinault 2353 22.83
1980 zoetemelk 2401 21.96
1981 hinault 2346 24.35
1982 hinault 2192 23.79
1983 fignon 2381 22.65
1984 fignon 2513 22.43
1985 hinault 2568 22.64
1986 lemond 2559 23.14
1987 roche 2644 22.90
1988 delgado 2054 24.32
1989 lemond 2053 23.43
1990 lemond 2190 24.14
1991 indurain 2446 24.21
1992 indurain 2489 24.69
1993 indurain 2321 24.19
1994 indurain 2486 23.99
1995 indurain 2272 24.49
1996 riis 2353 24.52
1997 ullrich 2469 24.56
1998 pantani 2320 24.99
1999 armstrong 2304 25.17
2000 armstrong 2289 24.73
2001 armstrong 2158 25.01
2002 armstrong 2049 24.96
2003 armstrong 2094 25.02
2004 armstrong 2119 25.35
jim beam
tim, if idiocy is simply picking a 3 decade gap from 2003, the last year
my tdf book covers, then i'm guilty. and i'm definitely not trying to
contend that chemistry has no influence on results, but the fact remains
that equipment today is measurably better. i have a cycling buddy who
is very evenly matched with myself in terms of ability. if i ride my
r540's, i can beat him. if he rides them, he beats me. that's a
non-lab test you can try yourself some time.
Tim McNamara
> On Wed, 20 Oct 2004 00:08:56 -0500, Tim McNamara
> <tim...@bitstream.net> wrote:
>
>>jim beam <nos...@example.net> writes:
>>
>>> sure - cross winds & head winds are never encountered outside of
>>> palo alto, so we can can all go back to 70's technology!
>>>
>>> 1973 tour de france average speed: 33.407kph 2001 tour de france
>>> average speed: 40.070kph
>>
>>jim, don't make yourself out to be an idiot if you don't have to.
>>Most of the time the wheels are not all that different from 1973.
>
> [snip]
>
> Dear Tim,
>
> Are the typical 2004 Tour wheels really "not all that different"
> from the typical 1973 wheels?
Not radically so, compared to say a few years ago when the Rev-X and
trispoke wheels were all the rage.
> Isn't the spoke count reduced?
>
> I'm not arguing that you were wrong about all the other things that
> improved times in the Tour, nor that reducing spoke count will or
> won't help in crosswinds.
Spoke count isn't significant in crosswinds IME- rim profile is,
however.
> But my impression is that modern low-spoke-count wheels are
> different enough that just tensioning them requires a different
> approach involving unloading the section of the rim around the spoke
> in order to turn the nipple.
For very low spoke count wheels, this is true. The rim has to be
pushed towards the originating spoke flange to reduce tension enough
to keep the nipple from binding.
> If I'm right, I still don't think that you're an idiot--just a
> little excited.
Annoyed rather than excited.
> If I'm wrong, I'll end up as a slightly smarter idiot, but still
> riding 36-spoke wheels
An excellent choice for all non-competitive riding, and a reasonable
choice for most competitive riding as well.
> Browsing through my god-fearing spreadsheet (miles, not kilometers),
> I see a general rising trend in average Tour speed, but 1973 was an
> unusually slow year--slower than any previous year back to 1954. Who
> was riding, what the weather was like, and the route chosen will all
> account for a lot of the differences.
>
> The post-war dates, distances, and average speed for the winner
> follow below. (No pre-war Tour winner reached an average of 20 mph.)
Nice data. Just to snip a few highlights:
> year winner miles mph
> 1956 walkoiak 2811 22.67
> 1958 gaul 2699 23.07
> 1962 anquetil 2671 23.32
> 1981 hinault 2346 24.35
> 1982 hinault 2192 23.79
> 1988 delgado 2054 24.32
> 1990 lemond 2190 24.14
> 1992 indurain 2489 24.69
> 2001 armstrong 2158 25.01
> 2002 armstrong 2049 24.96
> 2003 armstrong 2094 25.02
> 2004 armstrong 2119 25.35
So while speeds have gotten somewhat higher, we see that they weren't
exactly crawling along in, say, 1958 when Gaul won (probably carrying
a spare tubular on his back and a pump, riding over unpaved mountain
passes with stages often longer than is the case in the current
versions of the Tour). The increases in speed are due to a number of
reasons, probably none of which was spoke count. Improvements in
roads, lighter bikes, aerodynamic position in TTs, increase in
on-course support and in comunication technologies, etc all are part
of this increase in speed. I'm leaving out the cynical explanation,
since Gaul was universally thought to be a doper then.
Tim McNamara
> but the fact remains that equipment today is measurably better. i
> have a cycling buddy who is very evenly matched with myself in terms
> of ability. if i ride my r540's, i can beat him. if he rides them,
> he beats me.
This is 100% repeatable, in blind testing? Heck, I'd settle for 70%
repeatable in blind testing.
Peter Cole
>
> tim, if idiocy is simply picking a 3 decade gap from 2003, the last year
> my tdf book covers, then i'm guilty. and i'm definitely not trying to
> contend that chemistry has no influence on results, but the fact remains
> that equipment today is measurably better. i have a cycling buddy who
> is very evenly matched with myself in terms of ability. if i ride my
> r540's, i can beat him. if he rides them, he beats me. that's a
> non-lab test you can try yourself some time.
Analyticcycling.com cites references that aero wheels can reduce overall
drag by 2-3% over conventional wheels. That makes them good for TT racing,
but I'm not sure why anyone would want to use them outside of that, given
the disadvantages. Like Jobst says, without a stopwatch, you'd never
notice.
Generic, 36-spoke wheels - $200
Full fenders, with mudflaps - $40
Looks on faces when you ride the posers off your wheel - priceless.
David Damerell
>David Damerell <dame...@chiark.greenend.org.uk> wrote:
>>Chalo <chump...@hotmail.com> wrote:
>>>jim beam <nos...@example.net> wrote:
>>>>riding 16
>>>>spoke wheels however, the effect of cross winds is substantially less.
>>>OK, that's an issue I had not considered. The effects of crosswinds
>>>are not noticeable to me, even with 48 spoke wheels.
>>It's obvious nonsense, too; how do you suppose sock-boy imagines tandem
>>captains manage, with 48 spoke wheels and an extra rider stuck out the
>>back?
>To extend "jim beam" the benefit of the doubt, I'll point out that a
>tandem captain's situation is more like my own, with a heavily loaded
>front wheel that is unlikely to be pushed around by wind due to its
>sizeable contact patch. It's obvious if you ride one that a tandem
>requires more force at the bars than a single bike, especially a
>twitchy single.
I do ride one. It certainly requires more force at the bars, but it's by
no means unmanageable - even in heavy crosswinds, or with empty front
panniers (done that), or with no rider on the back.
Hence I don't believe for a minute that 20 extra spokes, with their
tiny area into the wind, present the slightest difficulty.
jim beam
hear hear! i have fenders on my commuter, and use 32 spoke wheels when
it's not windy. it's also dirty and gray to provide a little theft
deterrent in the city, so in that config, yes, it does drop jaws when
you ride past that $5k seven with all the trinkets. quite fun really.
>
>
jim beam
no it's not "blind", but we've done it 6 times during the course of this
summer with the results described. tim, bottom line, i'm not trying to
force these things down your throat - i'm merely voicing my experience.
based on that, yes, i'm confident there is a measurable difference if
i were to instrument the two sets of wheels, but as you know, i don't
work in the materials biz any more, so i can't say i have plans on
renting the equipment unless someone's paying me to do it. if you find
yourself here in the bay area some time, let me know and i'll loan you a
bike for a spin across the bridge. if you don't detect any difference,
at least you'll have enjoyed the view while trying.
Rick Warner
> no it's not "blind", but we've done it 6 times during the course of this
> summer with the results described. tim, bottom line, i'm not trying to
> force these things down your throat - i'm merely voicing my experience.
> based on that, yes, i'm confident there is a measurable difference if
> i were to instrument the two sets of wheels, but as you know, i don't
> work in the materials biz any more, so i can't say i have plans on
> renting the equipment unless someone's paying me to do it. if you find
> yourself here in the bay area some time, let me know and i'll loan you a
> bike for a spin across the bridge. if you don't detect any difference,
> at least you'll have enjoyed the view while trying.
I had a very different experience with the Ultegra version of the
wheelset, the 6500. Did not seem to be any faster on those wheels,
and did not like the feel of the ride. Much happier with my 32 spoke
Open Pro w/ Ultegra hub wheels on the same bike; just as fast, easier
to change tires, wheels not quite so stiff, and lighter to boot. Felt
lucky that some suck..., er, rider was willing to pay me close to what
I paid for the wheels.
- rick
carl...@comcast.net
<dame...@chiark.greenend.org.uk> wrote:
Dear David,
I wonder if it makes any difference that those 20 extra
spokes are spinning around 250 rpm when the rider is going
20 mph.
That is, in some ways spokes present a badly designed fan to
any crosswind, and 20 extra rapidly moving fan blades might
be different than 20 extra static wires.
Carl Fogel
jobst....@stanfordalumni.org
>> I do ride one. It certainly requires more force at the bars, but
>> it's by no means unmanageable - even in heavy crosswinds, or with
>> empty front panniers (done that), or with no rider on the back.
>> Hence I don't believe for a minute that 20 extra spokes, with their
>> tiny area into the wind, present the slightest difficulty.
> I wonder if it makes any difference that those 20 extra spokes are
> spinning around 250 rpm when the rider is going 20 mph.
You needn't wonder. The forward speed of the spoke does not affect
its lateral speed or the lateral drag it presents in a crosswind.
What does play a major role and has been reported by users here, is
that deep section aero rims cause significantly more interference
with steering in crosswinds.
> That is, in some ways spokes present a badly designed fan to
> any crosswind, and 20 extra rapidly moving fan blades might
> be different than 20 extra static wires.
Rotating speed has no effect on the lateral drag.
Jobst Brandt
jobst....@stanfordalumni.org
carl...@comcast.net
Dear Jobst,
Are you saying that a wheel's spokes (two faintly conical
arrangements) present the same resistance to a crosswind
whether the spokes are rotating or motionless?
Or am I misunderstanding you?
Carl Fogel
jobst....@stanfordalumni.org
> Are you saying that a wheel's spokes (two faintly conical
> arrangements) present the same resistance to a crosswind whether the
> spokes are rotating or motionless?
Yes.
Jobst Brandt
jobst....@stanfordalumni.org
jobst....@stanfordalumni.org
> Are you saying that a wheel's spokes (two faintly conical
> arrangements) present the same resistance to a crosswind
> whether the spokes are rotating or motionless?
Your question alludes to the concept that if a car is driven fast
enough it will or will not have a side thrust from a side wind.
In a way, saying if you go fast enough the wind won't see you.
Jobst Brandt
jobst....@stanfordalumni.org
jim beam
how? you have the forward vector, the sideways vector, and assuming a
ninety degree crosswind, an effective wind velocity that would be the
root of the sum of the other two vectors, squared.
jim beam
> jim beam <nos...@example.net> wrote in message news:<xJGdnS1hiaA...@comcast.com>...
>
>
>>no it's not "blind", but we've done it 6 times during the course of this
>>summer with the results described. tim, bottom line, i'm not trying to
>>force these things down your throat - i'm merely voicing my experience.
>> based on that, yes, i'm confident there is a measurable difference if
>>i were to instrument the two sets of wheels, but as you know, i don't
>>work in the materials biz any more, so i can't say i have plans on
>>renting the equipment unless someone's paying me to do it. if you find
>>yourself here in the bay area some time, let me know and i'll loan you a
>>bike for a spin across the bridge. if you don't detect any difference,
>>at least you'll have enjoyed the view while trying.
>
>
> I had a very different experience with the Ultegra version of the
> wheelset, the 6500.
i'm only aware of the wh-r535, wh-r540, wh-7700 & wh7701 for road.
what's the 6500 look like & what's its spoke count?
carl...@comcast.net
Dear Jim,
Far down on this page:
http://www.changing-gear.com/acatalog/CG_Catalog_Road_Wheels_188.html
Sixteen bladed spokes with a lubricating strip--er, sorry,
too many shaving commercials.
Rim height 30 mm.
The other wheels may be on the same page for comparison.
Carl Fogel
Dave Lehnen
No. Lateral force from a crosswind is not independent of forward
speed, whether or not that forward speed results from being part
of a rotating wheel, or just moving with the whole bike.
Consider a vertical round rod. When stationary, but in a side wind
of 10 mph, some sideways force F results. If the rod is now moved
forward at 10 mph, the apparent wind is 14.14 mph, and the force
magnitude is now 2F, with a sideways component of 1.414F and a
backwards component of 1.414F. For a forward speed of 20 mph,
apparent wind is 22.36 mph, force magnitude is 5F, with a sideways
component of 2.236F and a backwards component of 4.472F.
In a spoked wheel, the results can't be so easily calculated, since
the spokes are somewhat in the wake behind the leading part of the
wheel, but there is no reason to suspect that this effect would
exactly cancel the increase in side force due to drag being
proportional to velocity squared.
Dave Lehnen
jim beam
thank you!
Benjamin Lewis
> jobst....@stanfordalumni.org wrote:
>> Carl Fogel writes:
>>
>>> Are you saying that a wheel's spokes (two faintly conical
>>> arrangements) present the same resistance to a crosswind whether the
>>> spokes are rotating or motionless?
>> Yes.
>> Jobst Brandt
>> jobst....@stanfordalumni.org
>
> No. Lateral force from a crosswind is not independent of forward
> speed, whether or not that forward speed results from being part
> of a rotating wheel, or just moving with the whole bike.
>
> Consider a vertical round rod. When stationary, but in a side wind
> of 10 mph, some sideways force F results. If the rod is now moved
> forward at 10 mph, the apparent wind is 14.14 mph, and the force
> magnitude is now 2F, with a sideways component of 1.414F and a
> backwards component of 1.414F.
Where do you get "2F" from? It should be 1.414F, with a sideways component
of F and a backward component of F. The lateral force is independent of
forward movement.
--
Benjamin Lewis
All what we got here is American made.
It's a little bit cheesy, but it's nicely displayed. -- FZ
Benjamin Lewis
It's the sideways component of the wind velocity which is important in this
case, and this is not affected by forward movement.
Rick Warner
>
> i'm only aware of the wh-r535, wh-r540, wh-7700 & wh7701 for road.
> what's the 6500 look like & what's its spoke count?
Carl provided the link, but historically the 7700 and 6500 came out at
the same time and were basically the same wheels except for the hub,
the 7700 having DuraAce hub parts and the 6500 having Ultegra hub
parts. 540 was the next introduction, using 105 hub components but
basically the same design.
- rick
carl...@comcast.net
<bcl...@cs.sfu.ca> wrote:
>Dave Lehnen wrote:
>
>> jobst....@stanfordalumni.org wrote:
>>> Carl Fogel writes:
>>>
>>>> Are you saying that a wheel's spokes (two faintly conical
>>>> arrangements) present the same resistance to a crosswind whether the
>>>> spokes are rotating or motionless?
>>> Yes.
>>> Jobst Brandt
>>> jobst....@stanfordalumni.org
>>
>> No. Lateral force from a crosswind is not independent of forward
>> speed, whether or not that forward speed results from being part
>> of a rotating wheel, or just moving with the whole bike.
>>
>> Consider a vertical round rod. When stationary, but in a side wind
>> of 10 mph, some sideways force F results. If the rod is now moved
>> forward at 10 mph, the apparent wind is 14.14 mph, and the force
>> magnitude is now 2F, with a sideways component of 1.414F and a
>> backwards component of 1.414F.
>
>Where do you get "2F" from? It should be 1.414F, with a sideways component
>of F and a backward component of F. The lateral force is independent of
>forward movement.
Dear Jobst, Dave, Jim, and Dave,
Perhaps this page addresses the question?
"Several years ago, a debate raged among the members of the
University of Iowa Sailing Club as to whether or not you
should slow down if you were towing a big boat in a heavy
crosswind. (Actually, everybody agreed that slowing down was
safer. The disagreement was over why it was a good idea, so
the debate was really more about WHY, not WHETHER. But I
digress.) One position was that you could actually decrease
the SIDEWAYS force by reducing your FORWARD speed.....WOW!!
Let's see if this makes sense."
http://www.uiowa.edu/~sail/skills/trailerwind/
It ends up saying that "In other words, the sideways force
depends strongly on the forward speed."
Sailors--even Iowa sailors--tend to be interested in things
like crosswinds, so they might be more familiar with it than
bicyclists.
However, I'm not sure how far to trust the calculations of
an Iowa yacht club debate about how fast to tow boats behind
cars.
Still, any page whose intricate calculations refer to a
diagram with one element labelled "towed thing" deserves a
look.
Carl Fogel
Chalo
>
> David Damerell wrote:
>
> >Hence I don't believe for a minute that 20 extra spokes, with their
> >tiny area into the wind, present the slightest difficulty.
>
> Dear David,
>
> I wonder if it makes any difference that those 20 extra
> spokes are spinning around 250 rpm when the rider is going
> 20 mph.
>
> That is, in some ways spokes present a badly designed fan to
> any crosswind, and 20 extra rapidly moving fan blades might
> be different than 20 extra static wires.
I have speculated (idly, since I have read no relevant data) that
spinning spokes traveling forward through still air move largely
through air that is already turbulent, so that their drag in those
circumstances is not increased in proportion to their number.
However, it is clear that in any strong crosswind, each spoke would
stir up its own turbulent wake mostly independently of the others, and
thus their total drag in a crosswind would be in more or less direct
proportion to their number. And spokes do occur in such numbers that
their total drag, if each spoke adds the same amount to the total,
would certainly become significant even if their individual drag is
negligible.
In biplanes, round supporting wires became enough of an aerodynamic
constraint at fairly modest speeds that airfoil-shaped wires and
struts were quickly adopted. This was despite the fact that the
wires' frontal area was not a significant portion of the whole. Those
wing wires were not passing through the air as bicycle spokes do in
still air, trailing the tire and each other in close formation, but
rather in a manner comparable to a bicycle wheel in a crosswind, with
each wire dragging its own independent wake.
While it seems doubtful that any spoke drag would compare to the
amount produced by the rider and other portions of the bike, there
remains the possibility that it could play a role in steering forces.
The front wheel of a bike is aerodynamically unbalanced around its
steering axis, with 3 to 4 inches more wheel on one side of the axis
than on the other. In a bike that's particularly sensitive to
steering forces, strong or gusting crosswinds might be able to cause
steering anomalies separate from those caused by the push applied to
the rider.
Chalo Colina
Dave Lehnen
> Dave Lehnen wrote:
>
>
>>jobst....@stanfordalumni.org wrote:
>>
>>>Carl Fogel writes:
>>>
>>>
>>>>Are you saying that a wheel's spokes (two faintly conical
>>>>arrangements) present the same resistance to a crosswind whether the
>>>>spokes are rotating or motionless?
>>>
>>>Yes.
>>>Jobst Brandt
>>>jobst....@stanfordalumni.org
>>
>>No. Lateral force from a crosswind is not independent of forward
>>speed, whether or not that forward speed results from being part
>>of a rotating wheel, or just moving with the whole bike.
>>
>>Consider a vertical round rod. When stationary, but in a side wind
>>of 10 mph, some sideways force F results. If the rod is now moved
>>forward at 10 mph, the apparent wind is 14.14 mph, and the force
>>magnitude is now 2F, with a sideways component of 1.414F and a
>>backwards component of 1.414F.
>
>
> Where do you get "2F" from? It should be 1.414F, with a sideways component
> of F and a backward component of F. The lateral force is independent of
> forward movement.
>
I get 2F because drag force is proportional to speed squared, not to
speed. Because of this, lateral force depends on forward speed. If
drag increased linearly with speed, you would be correct, but it
does not.
Dave Lehnen
Benjamin Lewis
> Benjamin Lewis wrote:
>> Where do you get "2F" from? It should be 1.414F, with a sideways
>> component of F and a backward component of F. The lateral force is
>> independent of forward movement.
>
> I get 2F because drag force is proportional to speed squared, not to
> speed. Because of this, lateral force depends on forward speed. If
> drag increased linearly with speed, you would be correct, but it
> does not.
Hmm. Something seems counter-intuitive to me here, but I don't see any
fallacies in your argument. Interesting.
jobst....@stanfordalumni.org
> I have speculated (idly, since I have read no relevant data) that
> spinning spokes traveling forward through still air move largely
> through air that is already turbulent, so that their drag in those
> circumstances is not increased in proportion to their number.
> However, it is clear that in any strong crosswind, each spoke would
> stir up its own turbulent wake mostly independently of the others,
> and thus their total drag in a crosswind would be in more or less
> direct proportion to their number. And spokes do occur in such
> numbers that their total drag, if each spoke adds the same amount to
> the total, would certainly become significant even if their
> individual drag is negligible.
> In biplanes, round supporting wires became enough of an aerodynamic
> constraint at fairly modest speeds that airfoil-shaped wires and
> struts were quickly adopted. This was despite the fact that the
> wires' frontal area was not a significant portion of the whole.
> Those wing wires were not passing through the air as bicycle spokes
> do in still air, trailing the tire and each other in close
> formation, but rather in a manner comparable to a bicycle wheel in a
> crosswind, with each wire dragging its own independent wake.
I think you'll find that this was done to stop "Tacoma Narrows"
resonance effects rather than to reduce drag. Whether your reference
mentioned this or not, you should include this in your assessment.
You see power and communications cables in areas of strong crosswinds
equipped with spoilers or weights to prevent oscillation.
> While it seems doubtful that any spoke drag would compare to the
> amount produced by the rider and other portions of the bike, there
> remains the possibility that it could play a role in steering
> forces. The front wheel of a bike is aerodynamically unbalanced
> around its steering axis, with 3 to 4 inches more wheel on one side
> of the axis than on the other. In a bike that's particularly
> sensitive to steering forces, strong or gusting crosswinds might be
> able to cause steering anomalies separate from those caused by the
> push applied to the rider.
It is not the spokes that cause this problem, but rather the tire and
rim cross section (that is enormous in comparison to spoke cross
sections) and the trail of the wheel. As I said, this causes steering
torque and from experience, even a slight push on a rider's handlebars
can cause a crash. For those of us who have descended in stiff winds,
the effect is memorable, because it effectively pushes the rider out
of his lane (off the road).
Jobst Brandt
jobst....@stanfordalumni.org
jobst....@stanfordalumni.org
>>>>> Are you saying that a wheel's spokes (two faintly conical
>>>>> arrangements) present the same resistance to a crosswind whether
>>>>> the spokes are rotating or motionless?
>>>> Yes.
>>> No. Lateral force from a crosswind is not independent of forward
>>> speed, whether or not that forward speed results from being part
>>> of a rotating wheel, or just moving with the whole bike.
>>> Consider a vertical round rod. When stationary, but in a side
>>> wind of 10 mph, some sideways force F results. If the rod is now
>>> moved forward at 10 mph, the apparent wind is 14.14 mph, and the
>>> force magnitude is now 2F, with a sideways component of 1.414F and
>>> a backwards component of 1.414F.
>> Where do you get "2F" from? It should be 1.414F, with a sideways
>> component of F and a backward component of F. The lateral force is
>> independent of forward movement.
> I get 2F because drag force is proportional to speed squared, not to
> speed. Because of this, lateral force depends on forward speed. If
> drag increased linearly with speed, you would be correct, but it
> does not.
Yes, but your deriving the effective wind is for the evaluation of
in-line drag of the bicycle and rider for assessing rider power input
at any given speed. The side effect is unrelated to that and is
directly arrived upon by squaring the crosswind speed (times a
constant). The spoke is not moving laterally so the effect is
dependent on the cross wind speed only.
Besides, it should be noted that a crosswind assures that spokes do
not interact with one another because their wake trails of to the
side, leaving the following spoke in relatively clean air disturbed by
the passing of the tire only. This effect could actually nullify
spoke cross drag in the forward part of the wheel at higher speeds but
that is also immaterial because the higher the speed the more
sensitive is steering control.
Jobst Brandt
jobst....@stanfordalumni.org
Dave Lehnen
purpose. The rearward component is what affects power, which we
weren't discussing, it's the sideways component we were discussing.
It is absolutely mathematically invalid to look at the sideways
component of wind apparent velocity and square it to figure the
ratio of force to the no-forward-speed case. Of course there is a
constant, as you state, and for a vertical rod which has the same
shape and frontal area independent of wind direction, the constant
is the same for all cases. Since I said the first case of no forward
speed had some force F, it was not necessary to use the constant
which falls out in computing the ratio of forces.
Again, in the first case of no forward motion, but side wind only,
the vertical rod sees a pure 10 mph side wind. Force is 10 * 10 *
a constant depending on shape and size of the rod, and air density.
Let this force be 1.0 F, or if you prefer, 100*(const). The
direction of this force is purely sideways, since the vertical rod
generates drag only, and no lift.
In the second case, with 10 mph forward speed and 10 mph side wind,
the rod sees an apparent wind of speed 10 * sqrt 2, or about 14.14
mph, as a 45 degree quartering headwind. Force magnitude is
14.14 * 14.14 * (const), or 200*(const), so the force magnitude is
2.0 F. Its direction is 45 degrees to the rear of pure sideways.
The component we were discussing is the side component, which is
either sin(45 deg) * 200*(const), or 141.4*(const), or 1.414 F in
my original notation. The drag component, which isn't relevant to
the side force discussion, is cos(45 deg) * 200*(const) or
141.4*(const), or 1.414F. Sideways force is affected by forward
speed.
> Besides, it should be noted that a crosswind assures that spokes do
> not interact with one another because their wake trails of to the
> side, leaving the following spoke in relatively clean air disturbed by
> the passing of the tire only. This effect could actually nullify
> spoke cross drag in the forward part of the wheel at higher speeds but
> that is also immaterial because the higher the speed the more
> sensitive is steering control.
>
We weren't discussing spokes' interaction with each other. You have
often said in the past that spokes are too far apart from each
other, relative to their diameter, to draft each other to any
significant degree. I agree. In both the cases of crosswind at low
or zero forward speed, and at higher speeds, the spokes aren't
doing much drafting. You're right that at higher speeds, the spokes
run more in the draft of the leading portion of the tire and rim,
which I mentioned in my first post, but the chance of this effect
completelely cancelling the above effect at all speeds is slim
to none. Yes, steering sensitivity increases with speed, but this
is a separate issue from whether side force is forward-speed
dependent.
> Jobst Brandt
> jobst....@stanfordalumni.org
Dave Lehnen
jobst....@stanfordalumni.org
You are correct and that makes me think that the side wind effect gets
noticeably more with greater speed. The combination of greater
steering sensitivity (more rapid course excursions for small steering
motions) and the greater side drag which influence that. However, I
don't believe spoke drag has as large an effect as it may at first
seem, because spoke cross sectional area is tiny compared to tire and
rim cross section, the leading (important) edge of which is also
subject to this effect.
>> Besides, it should be noted that a crosswind assures that spokes do
>> not interact with one another because their wake trails of to the
>> side, leaving the following spoke in relatively clean air disturbed
>> by the passing of the tire only. This effect could actually
>> nullify spoke cross drag in the forward part of the wheel at higher
>> speeds but that is also immaterial because the higher the speed the
>> more sensitive is steering control.
> We weren't discussing spokes' interaction with each other. You have
> often said in the past that spokes are too far apart from each
> other, relative to their diameter, to draft each other to any
> significant degree.
I just thought this would be a point not to overlook, since it was
suggested that this is occurring in turbulent air that possibly
cancels the effect.
> I agree. In both the cases of crosswind at low or zero forward
> speed, and at higher speeds, the spokes aren't doing much drafting.
> You're right that at higher speeds, the spokes run more in the draft
> of the leading portion of the tire and rim, which I mentioned in my
> first post, but the chance of this effect completely canceling the
> above effect at all speeds is slim to none. Yes, steering
> sensitivity increases with speed, but this is a separate issue from
> whether side force is forward-speed dependent.
Yes, it is forward wind dependent.
Jobst Brandt
jobst....@stanfordalumni.org
Sheldon Brown
crosswind handling.
This is much more an issue of rider skill and confidence. People who
have a lot of trouble with crosswinds, I believe, are likely to be those
who ride with a "death grip" on the handlebars.
Skilled riders have a lighter touch on the bars, which makes crosswinds
much less of a problem.
Here's what happens: let's imagine a sudden puff of wind from your left
side.
The wind pressure from the left will tend to make the bike fall to the
right. To prevent such a fall, you need to turn the front wheel to the
right a bit to bring the wheels back under the bikes center of gravity.
If you look a the relationship between the front wheel and the steering
axis, you'll see that the steering axis runs a couple of inches behind
the center of the wheel. More of the wheel is in front of the steering
axis than is behind it.
Thus, a crosswind from the left will exert greater force on the part of
the front wheel that is forward of the steering axis, tending to make
the wheel turn to the right. As seen above, turning to the right is
exactly what is wanted to restore balance to the bike.
Experienced cyclists allow wind gusts to help them maintain balance this
way. Less experienced cyclists are liable to fight the torque on the
handlebars created by the wind blowing on the front part of the wheel,
and this is what causes most problems with crosswind handling.
Sheldon "Easy Does It" Brown
+------------------------------------------------+
| I’ll be appearing in: |
| Gilbert & Sullivan's Iolanthe at M.I.T. |
| November 12, 13, 14 and 18, 19, 20, 21 |
| http://web.mit.edu/gsp/www |
| http://sheldonbrown.com/music.html |
+------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
jobst....@stanfordalumni.org
> One kind of spoked wheel vs another really makes little difference
> in crosswind handling.
I'll agree to that... but
> This is much more an issue of rider skill and confidence. People
> who have a lot of trouble with crosswinds, I believe, are likely to
> be those who ride with a "death grip" on the handlebars.
> Skilled riders have a lighter touch on the bars, which makes
> crosswinds much less of a problem.
I see that you haven't ridden in gusty crosswinds or you forgot that
above about 40mph, you can't ride. As I reported about a ride over
Conway Summit US395, a contiguous 5-lane wide descent, I and my friend
got liberally blown across two lanes in the absence of traffic.
The next day on Tioga Pass HWY120 from Lee Vining, we got 100mph
headwinds that stooped us dead in our tracks while riding forward.
This required locking the brakes and standing legs spread behind the
bicycle. I have had conventional wheels in these conditions and it
doesn't take a hurricane to throw you off the bicycle with a 90 degree
side wind.
> Here's what happens: let's imagine a sudden puff of wind from your
> left side.
> The wind pressure from the left will tend to make the bike fall to
> the right. To prevent such a fall, you need to turn the front wheel
> to the right a bit to bring the wheels back under the bikes center
> of gravity.
It is not only the induced lean, which is to the wrong side, but the
steering that gets thrown off. The force in the bars is amazingly
disturbing with wind gusts. I hope you have the opportunity to ride
across such a wind some time.
> If you look a the relationship between the front wheel and the
> steering axis, you'll see that the steering axis runs a couple of
> inches behind the center of the wheel. More of the wheel is in
> front of the steering axis than is behind it.
All the theoretical assumptions will fall mute when you do it. I
assure you it is not trivial. I have ridden with good bicycle
handlers and we all had great difficulty in strong side winds. One
friend easily climbs hills standing while waving at folks with one
hand. He is a great track, and downhill rider. He and I know what
side winds do.
> Thus, a crosswind from the left will exert greater force on the part
> of the front wheel that is forward of the steering axis, tending to
> make the wheel turn to the right. As seen above, turning to the
> right is exactly what is wanted to restore balance to the bike.
> Experienced cyclists allow wind gusts to help them maintain balance this
> way. Less experienced cyclists are liable to fight the torque on the
> handlebars created by the wind blowing on the front part of the wheel,
> and this is what causes most problems with crosswind handling.
I seriously doubt it. I haven't seen anyone who can do this except in
less than 40mph side winds.
Jobst Brandt
jobst....@stanfordalumni.org
Ron Hardin
You will find that for riding _no-handed_ in crosswinds, that you want to
bolt a plate to the rearward half of the front wheel, so that it turns the
opposite way. This has nothing to do with gust performance but with
a steady crosswind, which otherwise has you riding akimbo holding the
front wheel to the left by leaning the frame to the left and yourself to
the right. After a few miles, this can be very wearing on you.
I dressed up a bicycle in school with such a plate, and it worked like a
charm, back when crosswinds were a perpetual fact.
That said, really serious sudden gusts blow you way off track. It's not
a matter of getting blown over so much as blown off the road. The front
wheel doesn't see the gust that hits you, which is considerably higher
up in altitude.
Probably somewhere around 40mph is where you want to be the only thing
on the road at the time.
--
Ron Hardin
rhha...@mindspring.com
On the internet, nobody knows you're a jerk.
jobst....@stanfordalumni.org
> You will find that for riding _no-handed_ in crosswinds, that you want to
> bolt a plate to the rearward half of the front wheel, so that it turns the
> opposite way. This has nothing to do with gust performance but with
> a steady crosswind, which otherwise has you riding akimbo holding the
> front wheel to the left by leaning the frame to the left and yourself to
> the right. After a few miles, this can be very wearing on you.
I think you are talking about breezes. You don't ride no-hands in
crosswinds.
> I dressed up a bicycle in school with such a plate, and it worked
> like a charm, back when crosswinds were a perpetual fact.
At what wind speeds and at what angle?
> That said, really serious sudden gusts blow you way off track. It's
> not a matter of getting blown over so much as blown off the road.
> The front wheel doesn't see the gust that hits you, which is
> considerably higher up in altitude.
Well? That's the kind of crosswinds I thought we were talking about.
> Probably somewhere around 40mph is where you want to be the only thing
> on the road at the time.
As I said, at 40mph crosswinds you can't ride. Below that, riding is
still difficult with hands-on.
Jobst Brandt
jobst....@stanfordalumni.org
Ron Hardin
> > You will find that for riding _no-handed_ in crosswinds, that you want to
> > bolt a plate to the rearward half of the front wheel, so that it turns the
> > opposite way. This has nothing to do with gust performance but with
> > a steady crosswind, which otherwise has you riding akimbo holding the
> > front wheel to the left by leaning the frame to the left and yourself to
> > the right. After a few miles, this can be very wearing on you.
>
> I think you are talking about breezes. You don't ride no-hands in
> crosswinds.
Crosswind refers to the direction, not the speed. Fruitless to argue
difinitions, I suppose. If you do a crosswind landing in aviation,
it doesn't mean the wind was strong. So there's already a definition out there.
It's useful because you do things differently in a crosswind.
I refer to a wind from the side that, riding no handed, causes you to have
to lean the frame into it, in order to hold the front wheel straight.
This is avoided if you balance the wind resistance of the front wheel, by
adding cross-section at the rear.
Then you can ride no-handed in comfort.
Doug Milliken
On Sun, 24 Oct 2004 jobst....@stanfordalumni.org wrote:
> Ron Hardin <rhha...@mindspring.com> writes:
>
> > You will find that for riding _no-handed_ in crosswinds, that you want to
> > bolt a plate to the rearward half of the front wheel, so that it turns the
> > opposite way. This has nothing to do with gust performance but with
> > a steady crosswind, which otherwise has you riding akimbo holding the
> > front wheel to the left by leaning the frame to the left and yourself to
> > the right. After a few miles, this can be very wearing on you.
>
> I think you are talking about breezes. You don't ride no-hands in
> crosswinds.
Very interesting idea to add an aerodynamic "tab" to your front wheel to
trim out the steer torque from constant modest crosswind. I assume that
the plate is actually attached to the front fork, not the rotating wheel??
Did you also consider adding a bungee cord (or other light spring) from
frame to one side of the handlebars to counter the steering torque? A
friend did this on a cross-country motorcycle trip when traveling on the
Great Plains with a constant side wind. Another example of adding a bias
to steering torque are "circle track" race cars which are often aligned to
pull to the left, such that the driver applies steering torque to the right
when driving on the straightaways.
Human powered vehicles with fairings have crosswind problems in spades.
Much lower wind speeds (than 40 mph quoted in this thread) can cause a
crash, or even lift the hpv in the air (think about carrying a sheet of
plywood in a stiff wind!) Here is the one paper that I know of which
attempts to analyze the situation:
http://www.ihpva.org/tools/cwind_stat_stab.htm
If the link doesn't work, the paper is available in other formats
at the bottom of this page under "Crosswind Stability paper":
-- Doug Milliken
www.millikenresearch.com
Tom Sherman
The "light spring" effect of a stretchable cloth fairing does help in
crosswind handling. I have ridden this bike [1] in winds exceeding
40-mph without any real problems. (The small diameter wheels certainly
help). Interestingly, the crosswind handling is the worst with just the
front bubble fairing and no bodysock.
Not all faired bicycles deal so well with winds - some are best kept out
of all but light wind conditions.
[1] <http://www.ransbikes.com/Gallery/Archive/images/Sherman1.jpg>.
--
Tom Sherman
Tom Sherman
As velocity increases, the length of the car decreases while the mass
increases, so the crosswind effect should be lessened. Of course, most
cars are about 6 to 7 orders of magnitude too slow for this effect to
become meaningful. ;)
--
Tom Sherman
Jeff Wills
<snip>
> Much lower wind speeds (than 40 mph quoted in this thread) can cause a
> crash, or even lift the hpv in the air (think about carrying a sheet of
> plywood in a stiff wind!) Here is the one paper that I know of which
> attempts to analyze the situation:
>
> http://www.ihpva.org/tools/cwind_stat_stab.htm
>
> If the link doesn't work, the paper is available in other formats
> at the bottom of this page under "Crosswind Stability paper":
>
> http://www.ihpva.org/tools/
>
> -- Doug Milliken
> www.millikenresearch.com
Well, the link worked for me.
I'll add an anecdote: I rode with some fully-faired (solid front,
fabric sides) Easy Racer recumbents through Troutdale, Oregon a couple
years ago. Wind speeds were a consistent 18 mph (see
http://www.wunderground.com/history/airport/KTTD/2002/11/16/DailyHistory.html
, noon to 1 PM). We had little difficulty negotiating the crosswinds,
riding at 90° to the wind direction. However, we were very happy to
turn and start running with the wind.
Jeff
Tom Sherman
Jeff Wills' comments are consistent with my experiences of riding LWB
recumbent bicycles with "bodysocks" in windy conditions.
--
Tom Sherman