With gritted teeth...

Another great write-up, and still an amazing ride both for distance and
average speed on a 24"...

Even allowing for the back problem, the ratio alone does not make the
uni the same as a Coker for speed.


And yes, you can do all the math you want about crank ratio and foot
speed but...

on a direct drive vehicle, the only way to really gear it up is a bigger
wheel...more distance travelled per rev. (Blue Shift excepted, that is,
of course)!

Chuck


--
Chuck Webb


I live in my own little world but its ok...they know me here!

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Chuck Webb wrote:
*you can do all the math you want about crank ratio and foot speed
but...

on a direct drive vehicle, the only way to really gear it up is a
bigger wheel...more distance travelled per rev. (Blue Shift excepted,
that is, of course)!*

Hmm. I'm not sure that that is technically correct: does a bigger wheel
gear up anything? Anyway, if you mean that the famous Constant Foot
Speed Hypothesis is worthless you should try various crank sizes. The
CFSH may have its weak points leading to such correction issues as a
'fear factor' but it surely has a right to live!

Klaas Bil - fan of the numerical approach


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Well, thank you both for your concern (this typed with a pen held in my
teeth as I lie on my bed of pain...)

I went into work today but had to give up and come home. I'm still
walking like Quasimodo.

The Constant Footspeed Hypothesis is, of course, a tongue in cheek
expression.

The idea is that (if you accept the hypothesis) your feet travel at a
given speed, whatever the size of the cranks. Therefore, if the cranks
are twice as long, it takes your feet twice the time to do one complete
revolution - or vice versa.

"Gearing" comes from the ratio between the length of the crank and the
radius of the wheel. This is because the circumference of the circle
your feet make is 2 x PI x R (where R = Radius = the length of the
crank) and the circumference of the wheel is also 2 X Pi x R (Where R =
the radius of the wheel).

So, the theory goes, if you have a 20 inch unicycle with 5 inch cranks,
or a 24 inch unicycle with 6 inch cranks, the ratios are the same. (5 =
half the radius of the 20 inch wheel; 6 = half the radius of the 24 inch
wheel.) For every yard/metre/cubit/pasang that your foot moves, the
wheel will move 2 yards/metres/cubits/pasangs.

(Anyone else sad enough to know about pasangs? :0) )

So applying this hyposthesis to the Coker (36 with 6 inch cranks) and
the 24 with 4 inch cranks, we see that the ratios are identical. Does
this mean that the unicycles have identical speeds? The question is too
simple.

We have to consider:
Maximum speed in a straight line on the flat
Average speed over a long journey on the flat
Average speed on a varied journey with obstacles
Comfortable cruising speed

It would be surprising to find that a 36/6 and a 24/4 would be identical
in all categories.

We can consider the matter easily by reductio ad absurdam (not quite the
normal use of the expression, I admit) and consider a 6 inch diameter
wheel with 1 inch cranks, and a 6 foot diameter wheel with 12 inch
cranks. Would either of these perform the same as the Coker? The
ratios are the same, but we don't need practical experiments to convince
us that given a choice of a 6/1, 36/6 and a 72/12 (all wheel
diameter/crank length in inches) only one would be a sensible coice for
speed or distance.

Similarly, the standard out of the box 20 has 5 inch cranks, the
standard out of the box 24 has 6 inch cranks. Would we expect similar
performance from them? To an extent, yes. But what about a 4 inch
wheel with 1 inch cranks, or a 40 inch wheel with 10 inch cranks?
Clearly not.

The Constant Footspeed Hypothesis is a useful guide when comparing the
perfomance of mid-range wheel sizes and crank sizes. The reason it
isn't completely accurate is that it excludes the most important part of
the unicycle: the rider.

The rider varies with:
Leg length
Ratio of lower leg length to upper leg length
Skill
Experience
Courage

Also, some riders are better able to apply lots of force slowly, whereas
others are better able to supply a small amount of force quickly. You
get sprinters, middle distance runners and Marathon runners. It's the
same with unicycling.

Anyway, by riding a long distance (24 miles) on a 24 with 102s, i have
been able to make a direct comparison with my experiences on a 28 with
110s and a Coker with 150s. According tot he hypothesis, the 28 should
be fastest (it isn't) and the Coker and 24 should be identical (they
aren't).

The answer seems to be, big wheels are generally faster than small
wheels, given broadly similar ratios. The 'gearing' of crank to wheel
is about the same, but the 'gearing' of thigh to wheel is different.


--
Mikefule - Roland Hope School of Unicycling

"Our greatest glory is not in never falling, but in rising every time we
fall."
Confucius
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Mikefule wrote:
*(Anyone else sad enough to know about pasangs? :0) )
*


no, but there isn't a form of 'wildlife'
(http://www.hyperdictionary.com/dictionary/pasang) i cant find with my
trusty old google machine




--
GILD - Waffle-tosser

The second half of a man's life is made up of nothing but the habits he
has
acquired during the first half.
-- Fyodor Dostoevsky


'pleez check this out' (http://www.reuniteluna.com/)

JUST SAY 'KNOW'!

Namaste!
Dave
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Not the meaning of 'Pasang' that I had in mind. :0)

Off topic at first:

If memory serves, the Pasang was a unit of measurement in the fictional
world or Gor, the setting for a huge number of blood 'n' guts and sword
'n' sworcery type fantasy books which were popular in the 1970s or
thereabouts. They had titles like, "Outlaws of Gor", "Swords of Gor",
"Dragon Riders of Gor" and so on. These may not be actual titles, but
I'm sure you get the idea. As a spotty teenager, I read many of them,
along with Brak the Barbarian (the poor man's Conan!), and Neq the
Sword, Var the Stck, Sos the Rope, and (most embarassingly) rather too
many of Ann(e) McCaffery's Dragonblurb novels.

The Pasang was a unit of measurement for distances we would measure in
miles or kilometres (as opposed to inches, yards, parsecs, centimetres
etc.)

My original reference to Pasangs was spontaneous. I knew the books were
about Gor. To research this particular post, however, I have checked
Google for 'Gor' and I found that the writer's name was John Norman.
Furthermore, there seem to be several websites devoted to "Gorean
philosophy," and the like, which suggests to me a 'fandom' similar to
that attached to Star Trek, Doctor Who, Blake's 7 and so on.

Back on topic: I believe John Norman has still to write the two future
classics of the gen Unicyclists of Gor, and Giraffe Riders of Gor.
Any plot suggestions? ;0)

As for the sympathy! If I'd cut my leg and posted a picture... but oh
no, I have to ride 6 miles, crippled with pain and nothing to
photograph. Miserable lot.


--
Mikefule - Roland Hope School of Unicycling

"Our greatest glory is not in never falling, but in rising every time we
fall."
Confucius
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Well, thank you both for your concern (this typed with a pen held in
my teeth as I lie on my bed of pain...)

Yes, please accept my sincere apologies...i got so caught up in your
beautiful prose, then started thinking about the wheel size/crank length
thing, and forgot all about your pain!

So...i offer my belated sympathy, and hope that you recover fully and
quickly so that we can once again read of your journeys!

Chuck


--
Chuck Webb


I live in my own little world but its ok...they know me here!

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Mikefule wrote:
*Well, thank you both for your concern (this typed with a pen held in
my teeth as I lie on my bed of pain...)*

Concern? Hm yeah, Mikefule I hope you feel better soon! But I know that
even the worst backpains go away. Been there done that. Pain or no pain,
I have to go through a set of neat exercises every couple of days to
keep it at bay.

Talking about concern, I was concerned though about the "attack" on the
elegant CFSH, launched by yourself maybe a year ago. It didn't come
across at the time as a tongue-in-cheek thing and I still regard it as a
valid first approximation albeit within a limited range. Hell, since the
CFSH was brought into daylight, I have timed myself more than a hundred
times on a variety of wheel and crank sizes out of sheer intriguedness
with the concept. Yes I will report some day.

I didn't know about Pasangs, not even about cubits I must admit. And a
yard? Well I've heard about that but there seems to be no standard yard;
just think of the Scotland yard and the back yard. So I will use the
S.I. system exclusively :-) .

Klaas Bil


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Klaas Bil wrote:
*
... And a yard? Well I've heard about that but there seems to be no
standard yard; ...*


In the USA, a yard is defined as three feet -- exactly 0.9144 meters.


--
duaner - -
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Mikefule wrote:
*Not the meaning of 'Pasang' that I had in mind. :0*


u say pasang, i say piesang...
(an attempted take-off of the tomeito/tomahto joke that requires u to
know that 'piesang' is the afrikaans word for banana in order to realise
that it's a) not funny, and
b) thoroughly irrelevant)



Mikefule wrote:
*If memory serves, the Pasang was a unit of measurement in the
fictional world or Gor, the setting for a huge number of blood 'n'
guts and sword 'n' sworcery type fantasy books which were popular in
the 1970s or thereabouts*


i've never heard of any of this but your mention of pasangs lead to a
fascinating afternoon's study of gorean philosophy
this is one of the main reasons i'm truly glad that i picked up
unicycling
i'm rather judgemental by nature despite the howls of disbelief from the
back of the audience
and in a previous (pre-uni) incarnation, would probably have looked at
the followers of gor and muttered something about 'get a life'
finding personal enjoyment atop one wheel seems to have tempered my
mutterings with a realisation that the high ground i'm attempting to
take in my judgement of the free time pursuits of others is rather
skinny

Mikefule wrote:
*which suggests to me a 'fandom' similar to that attached to Star
Trek*


now i have to wonder if trekkies look at this group as being 'weird'

Mikefule wrote:
*Back on topic: I believe John Norman has still to write the two
future classics of the gen Unicyclists of Gor, and Giraffe Riders
of Gor. Any plot suggestions? ;0)*


lots!!



--
GILD - Waffle-tosser

The second half of a man's life is made up of nothing but the habits he
has
acquired during the first half.
-- Fyodor Dostoevsky


'pleez check this out' (http://www.reuniteluna.com/)

JUST SAY 'KNOW'!

Namaste!
Dave
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Mikefule wrote:
*My route was from Trent Lock at Sawley up to the canal basin at
Langley Mill.*

Great write up Mike. Until you wrote this, I would never have thought of
riding up that towpath, probably because I find the landscape aound
LE/Ilkeston so ugly.

Glad yer gorom' OK, yoth.*


Phil

*Local slang meaing "Glad to hear that you made it home alright, old
chap.


--
Phil_Donaldson
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