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Eublapharis13
August 20th 03, 07:32 PM
OK.... me and my brother have a debate going on about the fastest
speed.. he says it's 18 MPH and i say it's 30 MPH can anyone help me
out?


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gerblefranklin
August 20th 03, 10:36 PM
What's the world record for highest speed on a unicycle w/o gliding or
coasting? 30mph seems pretty fast.


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daino149
August 21st 03, 07:30 AM
Anyone know the fastest speed of someone coasting?

Daniel


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Memphis Mud
August 21st 03, 06:44 PM
You would reach "terminal velocity" at around 120 MPH. But I assume you
mean riding ON the earth and not TOWARDS it.


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unibiker
August 21st 03, 07:38 PM
Memphis Mud wrote:
> *You would reach "terminal velocity" at around 120 MPH.*
Unless you're tracking head down with arms tucked back. Terminal
velocity increases to near 200 mph in this streamlined position.


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paco
August 21st 03, 08:12 PM
While we're on this topic, I remember someone saying that their personal
top speed on a Coker was something like 15 MPH. That seems pretty slow,
especially when I've gotten to 14 mph on my 24" (and offroad to boot!)


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gerblefranklin
August 21st 03, 08:31 PM
If you hit 120mph higher in the atmosphere you might go a bit faster
before you hit terminal velocity because of the lowered air pressure.


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rogeratunicycledotcom
September 1st 03, 10:45 PM
nathan wrote:
> *The highest speed I've heard of was between 29 and 30 mph by
> Christian. If I hadn't seen him ride I wouldn't think that's possible,
> given how fast and dangerous 20mph feels to me. Anyway, MANY people
> have gone well over 18mph.
> *


Christian is the man, he is certainly fast! I went for a little ride
him at eurocycle. It was fantastic, we sort of cruise at the same
speed.... it would be the one time I could not find my speedo but
Christain was saying it was around 30 kph that we found our comfortable
speed at. Faster than I thought it would be, but cool! isn't that
somewhere around 18mph.
As for my top speed, I have done 24mph but do not like going above
20mph... it scares me.

Roger


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Nathan Hoover
September 3rd 03, 03:46 AM
What do you have your cyclometer calibration set to?

Klaas Bil
September 3rd 03, 10:53 PM
On Wed, 3 Sep 2003 13:01:15 -0500, Ken Fuchs >
wrote:

>To calculate wheel size, one must ride a carefully measured one turn of
>the wheel or several turns / number of turns. Measuring my wheel
>without riding resulted in a circumference that was about 2% longer
>(2839mm) than measuring when riding (2834mm). Riding appears to
>compress the tire slightly, giving a smaller than expected
>circumference.

You've probably made a typo in the numbers or misplaced a decimal
point. The difference between those two rollouts is actually about
0.18%.

There is also an unclarity in my mind about the definition of 'speed'.
I can think of two definitions for speed. One is the circumference of
the wheel multiplied by the cadence, I call that tyre speed. The other
is the distance covered per unit of time, I call that road speed. The
two are different for (again) two reasons; for both of these, their
effect is in the same direction:

1. Wobble.
2. Tyre compression.

The first is fundamental, and it is a philosophical question what the
'best' definition of speed would be. The second could be avoided by
measuring the rollout while sitting on the uni. I measured the rollout
of my wheels when unloaded but when I sit on them the tyre compresses
and the effective wheel radius decreases. According to my
measurements, the two effects combined cause a difference on the order
of 3%.

Klaas Bil - Newsgroup Addict
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Klaas Bil
September 3rd 03, 10:56 PM
On Wed, 3 Sep 2003 13:01:15 -0500, Ken Fuchs >
wrote:

>To calculate wheel size, one must ride a carefully measured one turn
of
>the wheel or several turns / number of turns. Measuring my wheel
>without riding resulted in a circumference that was about 2% longer
>(2839mm) than measuring when riding (2834mm). Riding appears to
>compress the tire slightly, giving a smaller than expected
>circumference.

Ken, you've probably made a typo in the numbers or misplaced a decimal
point. The difference between those two rollouts is actually about
0.18%.

There is also unclarity in my mind about the definition of 'speed'. I
can think of two definitions for speed. One is the circumference of the
wheel multiplied by the cadence, I call that tyre speed. The other is
the distance covered per unit of time, I call that road speed. The two
are different for (again) two reasons; for both of these, their effect
is in the same direction:

1. Wobble.
2. Tyre compression.

The first is fundamental, and it is a philosophical question what the
'best' definition of speed would be. The second could be avoided by
measuring the rollout while sitting on the uni. I measured the rollout
of my wheels when unloaded but when I sit on them the tyre compresses
and the effective wheel radius decreases. According to my measurements,
the two effects combined cause a difference on the order of 3%.

Klaas Bil


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tomblackwood
September 4th 03, 08:18 AM
Klaas Bil wrote:
> *I can think of two definitions for speed. One is the circumference of
> the wheel multiplied by the cadence, I call that tyre speed. The other
> is the distance covered per unit of time, I call that road speed. The
> first is fundamental, and it is a philosophical question what the
> 'best' definition of speed would be. *

With all due respect....

Philosophy Shmilosophy.

If you're racing your Coker against a car, and when you get to your max
speed and they're still with you they yell their speedometer reading out
the window at you for encouragement, what is the number they're
yelling?

TB

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Klaas Bil
September 4th 03, 09:14 AM
tomblackwood wrote:
> *Philosophy Shmilosophy.
>
> If you're racing your Coker against a car, and when you get to your
> max speed and they're still with you they yell their speedometer
> reading out the window at you for encouragement, what is the number
> they're yelling?*

Thank you for the example because that refers precisely to my point. A
car has no wheel wobble to speak of - or something is terribly wrong. So
they are yelling your road speed (in my terms). If you have calibrated
your cyclometer on a straight (and loaded) rollout it measures your tyre
speed. The difference is (in my experiments) about 3%. Shmilosophy? You
may call it that but I wouldn't.

Klaas Bil


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Ken Fuchs
September 4th 03, 06:48 PM
>On Wed, 3 Sep 2003 13:01:15 -0500, Ken Fuchs >
>wrote:

>>To calculate wheel size, one must ride a carefully measured one turn of
>>the wheel or several turns / number of turns. Measuring my wheel
>>without riding resulted in a circumference that was about 2% longer
>>(2839mm) than measuring when riding (2834mm). Riding appears to
>>compress the tire slightly, giving a smaller than expected
>>circumference.

(Klaas Bil) wrote:

>You've probably made a typo in the numbers or misplaced a decimal
>point. The difference between those two rollouts is actually about
>0.18%.

Thanks for pointing out that error. The corrected sentence should read:

Measuring my wheel without riding resulted in a circumference that was
about 2% longer (2839mm) than measuring when riding (2789mm). A
difference of 50mm and not 5mm as previously stated.

>There is also an unclarity in my mind about the definition of 'speed'.
>I can think of two definitions for speed. One is the circumference of
>the wheel multiplied by the cadence, I call that tyre speed. The other
>is the distance covered per unit of time, I call that road speed. The
>two are different for (again) two reasons; for both of these, their
>effect is in the same direction:

>1. Wobble.
>2. Tyre compression.

My measurement didn't take into account wobble. I simply pedaled my
Coker exactly one rotation of the wheel on a straight line, next to a
support like a fence to help keep me straight. Thus, I measured the
wheel circumference with rider weighted tire compression, but definitely
wobble was not accounted for. I'm measuring tire speed with
compression; wobble effects should be included as well.

>The first is fundamental, and it is a philosophical question what the
>'best' definition of speed would be. The second could be avoided by
>measuring the rollout while sitting on the uni. I measured the rollout
>of my wheels when unloaded but when I sit on them the tyre compresses
>and the effective wheel radius decreases. According to my
>measurements, the two effects combined cause a difference on the order
>of 3%.

As I measured it, tire compression effectively reduces wheel
circumference by 1.76%. Taking Klass' total reduction of 3% and
subtracting the tire compression of 1.76% would give us a wheel wobble
reduction of 1.24%. However, this 1.24% doesn't mean much, because it
is a composite measurement of two riders, Klass Bil and myself.

Tire compression probably varies with rider weight, tire wear and tire
pressure.

Wheel wobble probably varies with speed, Q factor, rider leg, crank and
pedal mass. (Maybe rider skill can affect it too, but that might
as a side effect actually reduce speed; effort making the wheel wobble
less is not expended in actually making it go faster.)

So to get an accurate wheel circumference, one really should ride a long
accurately measured course in the way one expects to ride. One should
go about the speed one most often expects to go. The Q factor is a
constant for the Coker until the hub is changed. The Wobble mass is a
constant for the Coker and rider until the cranks/pedals are changed or
the rider bulks up (or loses weight in) his legs.

If one gets an accurate wheel rotation count, one can simply divide the
distance by the count to get the effective wheel circumference,
including both wobble and tire compression effects.

Otherwise, one can simply enter one's best guess of the effective wheel
circumference. Ride the measured course and compare the real (measured)
distance to the computer's distance. Compute the difference as a +/-
percentage and adjust the computer's circumference by the same
percentage.

Thank you Klass for your clear comments and insight into the bike
computer calibration problem for unicycles.

Sincerely,

Ken Fuchs >

tomblackwood
September 4th 03, 09:31 PM
Klaas Bil wrote:
> *Shmilosophy? You may call it that but I wouldn't.*


Deal.... ;)


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johnfoss
September 4th 03, 10:51 PM
The way speed is usually measured in sports competitions is by timing
something over a measured distance. This is how it's done for runners,
race cars, and bikes. This gives the rider the freedom to zig zag all
they want, or not, as whatever "speed" is contained in those motions
it's irrelevant to getting from A to B.

Onboard cyclometers are good for training and comparison from one ride
to the next, but are not real good for comparing one to another. To do
so accurately, calibration must be very accurate on the part of both
riders. It would (should) not be used in setting speed records, or
racing.

All of that said, there are a few "recognized" existing records out
there. We race 10k fairly regularly, though I don't know what the record
is. That should be researchable, and the fastest time is probably from
one of the last three UNICONs. Hopefully their 10k distances were all
accurately measured. This can establish for us a 10k speed record.

I remember reading a thing from 1888 or so, in which a guy went out and
established speed records in one mile increments all the way up to 14.8
or so. This was how far he got in an hour. In 1888! His wheel size is
unknown, but was probably in the range of common bike front wheels of
the day.

The IHPVA (International Human Powered Vehicle Association) keeps speed
records for various types of pedal powered vehicles. In 1986 or 7, Floyd
Beattie went to their meet in Indianapolis and set a "sprint" record,
using their 200 meter speed trap. To establish a record, you must ride
the course in both directions, and then the two times are averaged to
eliminate wind effects. He was riding on a brand new 45" Tom Miller big
wheel, that had just been assembled so he wasn't yet used to it. I don't
remember the details, but his times meant a speed of about 23 mph.
That's the only such record I know of for top speed over a short
distance. Even Floyd knows it wasn't that fast, and I'm sure he could
have gone much faster after getting acquainted with the cycle.

Floyd Beattie also did an hour record on a velodrome. He was a purist
about the whole thing, and only drank the water he carried with him,
refusing to pick up any he hadn't brought along. Anyway, he used up all
his water pretty quick, got dehydrated, and then had to "retire" in the
last few minutes to heave ho. He covered something like 14.89 miles,
about the same as the guy in 1888. This is from memory; not sure about
the exact numbers other than that it was real close to 15 miles.

Of course we know the 100 mile record is 6:44, which is amazingly fast
over such a long distance. That one is also supposedly the world record
for longest unicycle ride without a dismount (Takayuki Koike, 1987).

The Budweiser Rocket Car, making a run at the land speed record in 1982
or so, went up onto its single front wheel for more than 100' when
shockwaves formed on the rear part of the car. That's the world's
fastest *powered* unicycle. :)

Brett Bymaster has done gliding at speeds over 20mph, which is pretty
dang scary. He says he has approached 25, but I don't know if he ever
quite got there. That's just dangerous. Someone in Germany, maybe Arne
Tilgen (?) has gone over 40 kph gliding, while being towed by a
motorcycle.

Possibly the fastest glide I ever saw was done by Yuichiro Kato at
UNICON IV in 1988, at the world's first-ever Gliding competition. He
went flying down that hill at an unknown speed, his pedals a blur, until
he lost it and went sliding about 10m on his hands and knees.
Fortunately that was also the first year UNICON required everyone to
wear kneepads and gloves! He was unharmed. His second run was much more
conservative, and he didn't win. The winner of the contest was Fuyuki
Tsuchiya, who now works for Miyata and the JUA, and may be one of the
hosting persons at UNICON next summer.

Coasting? You just don't go fast. I've never seen anyone coast faster
than they do in one of our flat-ground coasting competitions. To do it
downhill would be spectacular to watch, but very dangerous for the
rider.

So, I believe what I've heard about Christian Hoverath. He's probably
the fastest unicyclist on earth, but it's unofficial. He's got to do
some kind of repeatable speed trap record for it to be a "real" record.
30mph? I'm not going that fast... :)


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nathan
September 4th 03, 11:05 PM
Good stuff John. According to Brett's (now dead) High Speed Gliding
page, he's gone 25.5mph gliding.

In case you're not really sure what gliding is, vs coasting, check out
these photos of Brett and John:
http://www.unicycling.org/unicycling/skills/glide.html

John, remember that time at Tahoe when Brett decided to glide down that
steep hill by the cabin before we left for Mr Toads? No safety gear, no
nothing, in seconds he was FLYING down that hill. I think he said that
run felt like under 20mph, so I'd hate to see 25.5.

---Nathan


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Klaas Bil
September 4th 03, 11:22 PM
On Thu, 4 Sep 2003 12:48:17 -0500, Ken Fuchs >
wrote:

>So to get an accurate wheel circumference, one really should ride a long
>accurately measured course in the way one expects to ride. One should
>go about the speed one most often expects to go. The Q factor is a
>constant for the Coker until the hub is changed. The Wobble mass is a
>constant for the Coker and rider until the cranks/pedals are changed or
>the rider bulks up (or loses weight in) his legs.
>
>If one gets an accurate wheel rotation count, one can simply divide the
>distance by the count to get the effective wheel circumference,
>including both wobble and tire compression effects.
>
>Otherwise, one can simply enter one's best guess of the effective wheel
>circumference. Ride the measured course and compare the real (measured)
>distance to the computer's distance. Compute the difference as a +/-
>percentage and adjust the computer's circumference by the same
>percentage.

That is all clear. Of course we have to bear in mind that the
difference between the two kinds of speed is only of the order of 1%,
as pointed out by Ken. So many people would consider the following
argument to be nitpicking; but hey, I like to pick a nit every now and
then :-)

It is a matter of taste what one should consider as the real speed (or
real distance, for that matter). Probably most would agree that road
speed is real speed, or 'effective' speed as Ken almost called it.
Yet, contradictorily (SP?), most people seem to calibrate their
computers on a straight-line rollout, sometimes even unloaded.

However, tyre speed (and distance) are equally real in their own
right. For one thing, tyre speed is the real physical speed with which
the tyre contact point travels. Also, tyre distance (as opposed to
road distance) determines tyre wear (combined with a lot of other
factors, including funnily enough wheel wobble in itself). And when
you race between a start line and a finish line 100 metres apart, the
wheel will actually have travelled (say) 101 metres, in a wobbly line
indeed.

Not being able to make a single choice in this matter, the spreadsheet
in which I record my road rides calculates both tyre speed and road
speed.

Klaas Bil - Newsgroup Addict
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johnfoss
September 5th 03, 12:33 AM
The high speed gliding page lives!
http://www.unicycling.com/brett/hsg.shtml

Brett hasn't maintained his content in a long time. He basically turned
it over to me, so it's waiting in line, behind my own site, to be
brought together and updated. That includes the "Official MUni FAQ,"
circa 1998 or so... :)


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Klaas Bil
September 5th 03, 01:02 AM
On Thu, 4 Sep 2003 12:48:17 -0500, Ken Fuchs >
wrote:

>So to get an accurate wheel circumference, one really should ride a
long
>accurately measured course in the way one expects to ride. One
should
>go about the speed one most often expects to go. The Q factor is a
>constant for the Coker until the hub is changed. The Wobble mass is
a
>constant for the Coker and rider until the cranks/pedals are changed
or
>the rider bulks up (or loses weight in) his legs.
>
>If one gets an accurate wheel rotation count, one can simply divide
the
>distance by the count to get the effective wheel circumference,
>including both wobble and tire compression effects.
>
>Otherwise, one can simply enter one's best guess of the effective
wheel
>circumference. Ride the measured course and compare the real
(measured)
>distance to the computer's distance. Compute the difference as a +/-
>percentage and adjust the computer's circumference by the same
>percentage.

That is all clear. Of course we have to bear in mind that the difference
between the two kinds of speed is only of the order of 1%, as pointed
out by Ken. So many people would consider the following argument to be
nitpicking; but hey, I like to pick a nit every now and then :-)

It is a matter of taste what one should consider as the real speed (or
real distance, for that matter). Probably most would agree that road
speed is real speed, or 'effective' speed as Ken almost called it. Yet,
contradictorily (SP?), most people seem to calibrate their computers on
a straight-line rollout, sometimes even unloaded.

However, tyre speed (and distance) are equally real in their own right.
For one thing, tyre speed is the real physical speed with which the tyre
contact point travels. Also, tyre distance (as opposed to road distance)
determines tyre wear (combined with a lot of other factors, including
funnily enough wheel wobble in itself). And when you race between a
start line and a finish line 100 metres apart, the wheel will actually
have travelled (say) 101 metres, in a wobbly line indeed.

Not being able to make a single choice in this matter, the spreadsheet
in which I record my road rides calculates both tyre speed and road
speed.

Klaas Bil


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tomblackwood
September 5th 03, 01:19 AM
Klaas Bil wrote:
> *Not being able to make a single choice in this matter, the
> spreadsheet in which I record my road rides calculates both tyre speed
> and road speed.*

That's really pretty hardcore... But I think it's nice that you'd have
at least three different potential answers to the question "How quickly
did your tyre wear out?"


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johnfoss
September 5th 03, 05:47 PM
Takayuki's 100 mile uni was a 43" air tire heavy thing. Those old wheels
had massive rims and tires that were designed for industrial use on
rickshaws or something similar. Heavy! I'm not sure about the crank
length. Probably around 125 but I don't know if I was ever told that.
Jack Halpern might know. I think the unicycle belonged to him, or was
the same as one he owned.

Takayuki was also racing with fellow 100-miler Floyd Beattie, who had
previously held the record. Floyd was probably on his 45" (unknown crank
length), but lost the race by a wide margin.

I think the terrain for the record ride was pretty flat. It was a bike
path, on which they rode back and forth. I think they even had to do
tight turnarounds at each end, but not sure about that. Again Jack
Halpern might be able to fill in some of the details.

If you are preparing for your first century, I would advise against
working toward survival. After you've got a few centuries under your
belt, you can shoot for the record. Takayuki's record is *way* beyond
all the previous 100 mile times, and impresses even bicyclists. I think
the second-fastest century on a unicycle is somewhere over 8 hours, but
I'm not sure. This should be researchable with old Guinness books.

Good luck on your century!


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johnfoss
September 5th 03, 08:04 PM
johnfoss wrote:
> *If you are preparing for your first century, I would advise against
> working toward survival. *
CORRECTION:
Remove "against!" I meant to say I advise against trying for that
amazing record on your first century attempt. It was not the first time
Takayuki had done it.


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john_childs
September 5th 03, 09:58 PM
Someone on a geared Coker might have a chance of breaking Takayuki
Koike's 100 mile record. Harper's hub is geared at 1:1.5 (one turn of
the pedals yields 1.5 turns of the wheel). Put that hub on a Coker
wheel and you've got about a 54" effective wheel. You could go quite
fast on that. I hope they wear appropriate safety equipment because a
UPD at that speed would be nasty. A German fellow has a geared hub that
is geared at around 1:1.67 which would give a Coker wheel a 60"
effective diameter. Someone is going to challenge the 100 mile record
and it will probably be on a geared up Coker wheel.

But 6:44 for a 100 mile ride on a unicycle is amazing. I'd be happy
doing a century in 6:44 on a bike (but I take rest stops when I do a
century on a bike :) )


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iunicycle
September 5th 03, 11:21 PM
Klaas Bil wrote:
> *
> Not being able to make a single choice in this matter, the spreadsheet
> in which I record my road rides calculates both tyre speed and road
> speed.
> *


Hmm, if there is a constant linear relationship between the two numbers,
isn't maintaining both like reporting tire diameter and circumference?

I'm sure the relationship isn't linear, but I doubt anyone has the
equipment to make anything other than a guess at wheel speed.

However, I can see you point. I would not like to brag about my wages
after taxes have take their nibble, which is far greater than 3%.


--
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GizmoDuck
September 6th 03, 03:42 AM
johnfoss wrote:
> *CORRECTION:
> Remove "against!" I meant to say I advise against trying for that
> amazing record on your first century attempt. It was not the first
> time Takayuki had done it. *


Thanks John. That certainly is pretty amazing. I make that to be an
average speed of 23.76km/h! But I was afraid you were going to say he
rode a 24' unicycle, not that it makes it any less impressive!

I took my Coker for a 30km spin today and managed little over 20km/h :(
That was over fairly hilly terrain with 150mm cranks. I think I'd be
able to do 160km with a bit of training, but I doubt I'd average much
more than 20km/h even with shorter cranks. Realistically we're aiming
for 8-10hrs. There should be quite a few of us doing this ride so
hopefully we'll go faster (As a Coker peleton????- is there such a
thing???) I wonder if drafting at 20km/h will save us a few minutes
over 160km? :D


--
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"I'll be there with bells on!"
Tony on the NZUni weekend

"right thats it im dressing up like a woman!"
James on the NZuni weekend

"If not for a weird inner ear condition that prevents me from crossing
the equator, I'd be there too."
JJuggle- the most original excuse not to attend the NZUni weekend

"At least if someone hurts themselves, Ken should be able to fix them up
with brain surgery on the spot if he brings a scalpel and some
bandages."
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Klaas Bil
September 7th 03, 11:39 PM
On Fri, 5 Sep 2003 15:58:49 -0500, john_childs
> wrote:

>A German fellow has a geared hub that
>is geared at around 1:1.67 which would give a Coker wheel a 60"
>effective diameter.
You probably mean Frank Bonsch? His hub gear ratio is actually
1:1.5833 so the Coker would effectively be 57".

Klaas Bil - Newsgroup Addict
--
If the crank is moving then it really sounds as if it's loose. - onewheeldave trying to pinpoint the cause of a clicking crank

Ken Fuchs
September 8th 03, 01:58 AM
john_childs > wrote:

>Someone on a geared Coker might have a chance of breaking Takayuki
>Koike's 100 mile record. Harper's hub is geared at 1:1.5 (one turn of
>the pedals yields 1.5 turns of the wheel). Put that hub on a Coker
>wheel and you've got about a 54" effective wheel. You could go quite
>fast on that. I hope they wear appropriate safety equipment because a
>UPD at that speed would be nasty. A German fellow has a geared hub that
>is geared at around 1:1.67 which would give a Coker wheel a 60"
>effective diameter. Someone is going to challenge the 100 mile record
>and it will probably be on a geared up Coker wheel.

I would agree almost 100%, John! I would rule out big wheels larger
than the Coker. Direct ride may still triumph!

>But 6:44 for a 100 mile ride on a unicycle is amazing. I'd be happy
>doing a century in 6:44 on a bike (but I take rest stops when I do a
>century on a bike :) )

John Foss reminded us that Takayuki's unicycle for this Guinness record
was a 43" wheel with pneumatic tire. It is still extremely impressive
that he did that 100 mile ride in 6:44, since he averaged 14.85 MPH for
nearly 7 hours!

Sincerely,

Ken Fuchs >

john_childs
September 8th 03, 02:43 AM
Klaas Bil wrote:
> *On Fri, 5 Sep 2003 15:58:49 -0500, john_childs
> > wrote:
>
> >A German fellow has a geared hub that
> >is geared at around 1:1.67 which would give a Coker wheel a 60"
> >effective diameter.
> You probably mean Frank Bonsch? His hub gear ratio is actually
> 1:1.5833 so the Coker would effectively be 57".
>
> Klaas Bil - Newsgroup Addict
> *

Yes, I was thinking of Frank Bonsch.
I somehow got in in my brain that his hub was 1:1.67 which is incorrect.
Harper has corrected me on that on more than one occasion.

Now that you have reminded me of his name I can find his web site.
'UniFrank' (http://www.unicycle.de.vu/)
He has a picture of his hub under "unicycle prototype"

The big advantage to Frank's hub ratio is that it will result in even
tire wear. Harper's hub ratio of 1:1.5 will still cause tire wear in
two spots so you'll still need to rotate the tire on the rim to get even
tire wear.


--
john_childs - Guinness Mojo

john_childs (at) hotmail (dot) com
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showard
September 8th 03, 04:01 AM
Hey! I can nit pick too!

Klaas wrote:

> You probably mean Frank Bonsch? His hub gear ratio is actually
> 1:1.5833 so the Coker would effectively be 57".


From Ken Fuchs' Coker tire roll out dimensions I calculate the effective
diameter of a Coker tire to be 34.7" so with the Frank Bonsch hub the
Coker would be effectively 55".

John Childs wrote:

> The big advantage to Frank's hub ratio is that it will result in even
> tire wear. Harper's hub ratio of 1:1.5 will still cause tire wear in
> two spots so you'll still need to rotate the tire on the rim to get
> even tire wear.


Actually Harper's hub will result in *four* wear spots 90 degrees apart
instead of two. Also John, you forget about switching the hub to 29"
mode ... there's three possible places to anchor the arm dingus so if
the hub is switched from 29" to 43.5" often, the tire should wear fairly
even.

To further nit pick ...

I measure the roll out circumference of the 29" Big Apple to be 89.6".
That's a diameter of 28.52" so the Harper hub actually makes an
effective wheel diameter of 42.8" ... with that tire anyway.

So there!! :)

Steve Howard


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tomblackwood
September 8th 03, 04:09 AM
showard wrote:
> *Actually, Harper's hub will result in *four* wear spots 90 degrees
> apart instead of two. *

Speaking on behalf of myself and the other idiots I represent, I must
ask "Why"? The uni appears to roll forward in a consistent manner, so
why would there be four wear places? I understand why on a giraffe
which gets idled a lot over the same part of the tire, but don't see why
it would happen on a uni that doesn't get idled (much) and pretty much
just does distance or speed riding.


--
tomblackwood - Registered Nurtz

My other brake is my face!

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johnfoss
September 8th 03, 10:35 PM
GizmoDuck wrote:
> *I wonder if drafting at 20km/h will save us a few minutes over 160km?
> :D *
Based on my uni racing experience I can't recommend it. When done by
bicyclists with lots of training and racing experience, drafting can
still be fairly dangerous. Add the extra things that can go wrong on
unicycles at high speeds, along with what I think would be a reduced
aero benefit, and the return would seem to diminish quite a bit.

For those not familar with the situation, these are things that can go
wrong in a drafting situation:

1. Rider in front falls--guaranteed fall for rider in rear, plus landing
on front riders' unicycle.

2. Touching tires front to back. If they touch pretty hard, it can throw
off both riders--see #1.

3. Overlapping wheels--since our wheels generally don't go straight but
have some wobble, this could be disasterous. If the wheels touch and the
rider's center of mass is in the wrong place, it might be impossible to
recover from the position.

Coker riders are generally going slower than bike in a race, so the
amount of advantage you get from drafting will be less. I don't know if
the riders' bodies are any closer than bike bodies, but the fact that we
generally sit up much straighter, and are less aerodynamic, may increase
the amount of "benefit" you could get from drafting.

But for me, I don't think it would be worth the risk.


--
johnfoss - Now riding to work

John Foss
the Uni-Cyclone
www.unicycling.com
________________

"Where's my kids?" -- Amy Drummond
"Where's my unicycle?" -- Andy Cotter
spoken one right after the other, mostly to themselves, at NAUCC 2003

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john_childs
September 8th 03, 11:49 PM
johnfoss wrote:
> *Based on my uni racing experience I can't recommend it. When done by
> bicyclists with lots of training and racing experience, drafting can
> still be fairly dangerous. Add the extra things that can go wrong on
> unicycles at high speeds, along with what I think would be a reduced
> aero benefit, and the return would seem to diminish quite a bit.
> *

The general rule on bikes is that you need to be going over 15 to 17 mph
(24 to 27 kph) before drafting becomes worth it. Below those speeds you
are not getting enough of a draft off the front rider to give you much
benefit. At speeds above 20 mph (32 kph) drafting gives you a very
noticable advantage on a bike.

The thought of drafting another unicyclist at 17 mph is craziness. Too
much risk of a very high speed UPD and a bad crash. Dangerous.

However, drafting behind a bike at 17 mph would be a little less crazy,
but still crazy. You'd need the bike to cooperate and maintain a very
consistent speed. It would be an exercise in intense concentration on
the part of the bicyclist to be able to maintain a very consistent speed
and communicate with the unicyclist about speed, road conditions, etc.
The bicyclist would also have to sit up to create as big of a windbreak
as possible.

Drafting at 17+ mph on a unicycle would be something to put on John
Foss' Things Not To Do page.


--
john_childs - Guinness Mojo

john_childs (at) hotmail (dot) com
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nathan
September 9th 03, 12:40 AM
I've done A LOT of drafting on bikes, and John Childs is exactly right -
it's generally not helpful below something like 17mph. Biking in a
tight paceline at 25-30mph is a fantastic feeling and not all that crazy
as long as everyone knows what they are doing. This is where your front
tire is 1 to 6" from the rear tire ahead of you. (Sometimes even
touching!)

I've "drafted" on a unicycle going 10-12 mph (for photos), but it isn't
really drafting - you're just riding behind the person in front.

There is one case where drafting on a unicycle actually makes sense: in
a headwind. If you are able to push say 8-10mph into a 15mph wind, you
actually do get some benefit from drafting. The reason is that John's
15-17mph isn't the speed of the cyclist, it's the speed of the cyclist
plus the headwind. So you're relative speed to the air here is 23-25mph.
Be very careful doing this on a unicycle!

---Nathan


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harper
September 9th 03, 01:43 AM
showard wrote:
> *... there's three possible places to anchor the arm dingus so if the
> hub is switched from 29" to 43.5" often, the tire should wear fairly
> even.
>
> *


To add further complication, when the wheel is stationary and the torque
arm (arm dingus) is rotated one full turn, the pedals rotate one half
turn. In reality, then, there are six unique positions of the pedals
with respect to the wheel in direct drive, or 29", mode, not three.

And to further nitpick, the contraction "there's" is completely
inappropriate here in that it should take a singular predicate
nominative rather than the plural, "places". The irregular contraction
"there'r" would be appropriate in this sentence. Now we're jacking this
thread with two tangential topics. Cool.

Finally, it is part of my belief system (as opposed to something I know)
that Frank's hub gears up by 1 and 4/7 or 1.57 something. This could be
something I made up knowing that the numerator and the denominator must
be integers of reasonable values.


--
harper - Old dog, no tricks

-Greg Harper

B L U E S H I F T

"I managed to get my missus riding a couple of yards before she got
pregnant with Jenny, but she hasn't tried riding since. " - Danny
Colyer

"Sa da tay! Sepotown!" - Pootie Tang


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Klaas Bil
September 10th 03, 01:56 AM
On Mon, 8 Sep 2003 19:43:43 -0500, harper
> wrote:

>Finally, it is part of my belief system (as opposed to something I know)
>that Frank's hub gears up by 1 and 4/7 or 1.57 something. This could be
>something I made up knowing that the numerator and the denominator must
>be integers of reasonable values.

Frank initially stated that his hub's gear ratio was 1.57. For that
reason the machine has been (or is?) known as uni.57. However when I
asked about the exact value (about 1.5 years ago I think) he said that
it is actually 114/72, or 1.583333.

Interestingly, if this hub were mounted on a Coker with its nominally
36" tyre, it gears up to exactly 57" (nominally, I must add again
before Steve H picks that nit again). That machine could become known
as Coker.57.

Klaas Bil - Newsgroup Addict
--
If the crank is moving then it really sounds as if it's loose. - onewheeldave trying to pinpoint the cause of a clicking crank

Ken Fuchs
September 10th 03, 02:13 AM
GizmoDuck wrote:

> *I wonder if drafting at 20km/h will save us a few minutes over 160km?
> :D *

I'm sure that GizmoDuck is not serious. One good reason is drafting at
20 km/h (12.4 mph) is too slow for wind resistance to have much effect
and thus drafting will have minimal effect as well. Wind resistance is
proportional to the cube of wind speed. I vaguely recall that wind
resistance is not a big factor until 20 mph (or was that 20 km/h :).

Sincerely,

Ken Fuchs >

Mike Peterson
September 11th 03, 12:46 AM
I feel obliged to point out that although I'm riding really fast on my
Coker every single day I wear a helmet and wrist guards on EVERY ride. As
far as the high-speed UPDs I have substantial training in Aikido and have
developed enough skill in the art to actually roll out of my UPDs. Not roll
on my unicycle but to take a roll. Frequently my falls occur at about 20
mph. Usually the first thing that happens after I UPD is to tap my foot off
of the ground and launch myself through the air for a huge forward roll.

I realize the risks of what I'm attempting and try to prepare myself for
the worst. Whether I'm racing on BMX tracks with my unicycle, leaping on
obstacles at the skate park or simply racing along as fast as possible I
make sure that my safety gear and skills are all ready to protect me. Don't
try something extreme just because it has been accomplished before.

Mike Peterson
Eugene, OR
Come visit Mike's Home for Wayward MiB agents at:
http://gladstone.uoregon.edu/~mpeters1

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