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"The Stability of the Bicycle"



 
 
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  #161  
Old October 17th 03, 07:10 AM
Carl Fogel
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Simon Brooke wrote in message .uk...
(Carl Fogel) writes:

While I'm not following the fray, I noticed your interest in
the speed of hand-spinning, a question that caught my interest
earlier in an unrelated thread about rotating mass, where I made
a rude reply to a post in which a bet was made that the wheel
could be spun up to 30 mph with one finger.

Surprisingly, it's damned hard to hand-spin a 700c wheel to
even 15 mph, even though ordinary people can easily throw a
baseball twice as fast (and four to six times as fast with
effort).


Yes, I and my partner found that too. We couldn't get above 9mph on
the clock by hand spinning. Mind you I'm not doubting that other
people have got more, merely surprised at how slow it was.

If the speed of Simon's spinning interests you, it's
probably possible to calculate it reasonably accurately.
If you look closely, he has a spoke-reflector that will
let you count and time spins of what appears to be a
700c tire--a little number crunching and there we are!


27 inch, actually, but it makes little difference.


Dear Simon,

Actually, I think that 9 mph is respectable, given the
tire-spinning technique that you used in your movies,
where you were dealing with a bicycle suspended from
ropes and not likely to be interested in how fast you
could get the silly thing to spin.

My (modest cough) 15 mph record (hey, it's lasted at
least one post) was set with the bike standing firmly
upside-down on a garage floor, a firm grip on the tire,
a wind-up, and a mighty heave--plus a few mulligans.

My approach would have bounced your dangling bicycle's
front wheel off the turf and ruined your experiment, so
there's absolutely no shame in your humiliating second-place
finish, as I just finished emailing my Red Sox sister in Boston.

Front tire spinning standings:

1. Carl Fogel (unassisted 700c) 15 mph
2. Simon Brooke (assisted 27") 9 mph

More to come?

Carl Fogel
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  #162  
Old October 17th 03, 11:08 PM
Mark Hickey
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(Carl Fogel) wrote:

My (modest cough) 15 mph record (hey, it's lasted at
least one post) was set with the bike standing firmly
upside-down on a garage floor, a firm grip on the tire,
a wind-up, and a mighty heave--plus a few mulligans.

My approach would have bounced your dangling bicycle's
front wheel off the turf and ruined your experiment, so
there's absolutely no shame in your humiliating second-place
finish, as I just finished emailing my Red Sox sister in Boston.

Front tire spinning standings:

1. Carl Fogel (unassisted 700c) 15 mph
2. Simon Brooke (assisted 27") 9 mph

More to come?


But of course...

I think I started this whole "how fast can you spin a wheel" when I
suggested that I spun up the front wheel on my fixie to 15-20mph.

Alas, I probably didn't.

But I don't have a speedo on any of my "current bikes"... the best I
could do is to drag down an old (but lovely...) steel bike of my
wife's that still has a working speedo. Unfortunately, the pickup is
on the rear wheel, so spinning it "the easy way" was out of the
question (since it would engage the pawls, and take the chain and
cranks along for the ride).

With a single, awkward, upside-down spin, I got 14mph. It was
probably a bit higher, judging from the decay rate and the time it
took for the speedo to register. But now I DO doubt I actually spun
the front wheel 20mph. Maybe 15 though (which means I was actually
underestimating the gyroscopic effect a bit.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
  #163  
Old October 18th 03, 03:41 AM
Carl Fogel
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Mark Hickey wrote in message . ..

[snip]

Dear Mark,

Sorry, but honesty isn't the best policy. Decay rate
won't wash, the speedometer has spoken, we measure real
horsepower at the rear wheel, not what might be happening
above the wrist-pin!

You said 14 mph and that's all you get.

You really can't complain. We're letting you slip in a
rear wheel spin and only punning on your lovely wife's
rear in the standings. Hope she appreciates it, though
I don't recommend slapping at it.

We trust everyone to use the finest speedometers
available, to calibrate them to the measured size of
their front tires honestly, and to have another go
until this kind of important competition is settled!

(Incidentally, the front wheel of a penny-farthing
would give vastly improved leverage, so we'll have
to outlaw them, sort of like aluminum bats and mortars
for deer-hunting.)

(And no, this thread-digression is not your fault,
though you may well have raised it elsewhere. I
can't seem to figure out how to put the link to
my original rude post, so it's appended below.)

Front tire spinning standings:

1. Carl Fogel (unassisted 700c) 15 mph
2. Mark Hickey (lovely wife's rear) 14 mph
3. Simon Brooke (assisted 27") 9 mph

More to come?

Carl Fogel

Original spinning post from different thread:

From: Carl Fogel )
Subject: Argument - rolling mass negligible or not?
View this article only
Newsgroups: rec.bicycles.tech
Date: 2003-10-07 14:13:02 PST

"GWB" wrote in message om...
. . . Take a wheel hooked up to a
speedo, lift it off the ground a bit. I'll bet you can get that wheel
spinning to show 30 mph on the speedo with one finger. It doesn't take
much power to move a wheel, heavy or light.


Dear GWB,

Can you really spin a dangling front wheel attached to a speedometer
up to 30 mph easily with a single finger? From what I've seen of
calculations on rec.bicycle.tech, it actually takes quite a bit of
power, speed, and leverage to spin a spoked 700c wheel up to such
speeds.

I'm old and slow and sluggish (and so is my front wheel), but 15 mph
was roughly what my max-reading kept reporting after I slapped wildly
at the spinning tire with my hand instead of a single digit (and I
cheated by flipping my bike upside-down so that I could take a good
crack at the wheel.)

The fastest track sprinters are said to reach only about 27 mph
about 2/3 of the way down the 100 meter track using their legs,
which are much longer and faster than their arms and fingers.
The fists of boxers are commonly thought to reach only 20-25 mph.
Baseballs are thrown at much higher speeds, but then the arms
involved follow much greater arcs than are available to fingers
urging 700c wheels.

Perhaps you meant hooking a speedometer up to a rear wheel and
using a single finger on the pedals to spin it up? You might gain
the necesssary leverage, but it still sounds like one impressive
finger that you're giving us.

So no betting--what's the max-speed that you and your friends
actually record spinning a front wheel with one finger? The
experiment takes only a minute or two, so I hope to hear from
other researchers. If nothing else, think of the amusing spectacle
of bicycle geeks in garages everywhere grimly stroking dangling
wheels with single fingers. Surely younger folk with lighter
aero-wheels can improve on my pitiful 36-spoke performance.

But do resist the temptation to gain leverage by sticking your
finger into the spokes near the hub--you'll likely break a finger.

Carl Fogel
  #165  
Old October 20th 03, 04:25 PM
Robert Strickland
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2. Mark Hickey (lovely wife's rear) 14 mph

no comment


  #166  
Old October 21st 03, 07:08 AM
Mark Hickey
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Default "The Stability of the Bicycle"

"Robert Strickland" wrote:

2. Mark Hickey (lovely wife's rear) 14 mph


no comment


I was thinking the same thing...

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
  #167  
Old October 21st 03, 08:47 PM
Carl Fogel
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Default "The Stability of the Bicycle"

Mark Hickey wrote in message . ..
"Robert Strickland" wrote:

2. Mark Hickey (lovely wife's rear) 14 mph


no comment


I was thinking the same thing...


Dear Rob and Mark,

No comment? Thinking the same thing?

Bah! You sound like spineless politicians,
not fearless, forthright, virile cyclists!

Mark's lovely wife must be thinking
as she spins her well-equipped rear
wheel (speedometer and all), "Only
the brave deserve the fair."

Carl Fogel
  #169  
Old October 22nd 03, 05:02 PM
g.daniels
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Default "The Stability of the Bicycle"

gyroscope head??
i can't ride but i can think.downwind mostly. swoop swoop
maybe ya'll need a 130 moph fairinging cosworth sounding motor to devo understanding
or a gyro and a string.
no insurance!
 




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