PING ALL COKEURS: Share your rollout data (Was What circumference did you ent...

On Mon, 8 Sep 2003 13:49:52 -0500, johnfoss
wrote:

So I'm fine with a nice, median number. That's why I would be
interested
to hear the results people are getting, in the form of circumference
numbers, listed along with those other factors mentioned above. If
several people do this, the rest of us (the lazy ones) may be able to
make pretty accurate extrapolations from that data.

Even though I don't own a Coker yet, I volunteer to process the data
(if enough comes in) into a formula that estimates rollout from
A. rider weight,
B tyre pressure and
C tread wear (as an estimated percentage).

Please state also whether the rollout is
1) unloaded and in a straight line, or
2) loaded and in a straight line, or
3) from a ridden distance so that wobble is included. You may want to
include additional data (speed, surface type etc) but it may be
overkill.

Data are best posted here (as opposed to sent via e-mail) so that they
are publicly available. The few that have been posted in this thread
need no repeat but you might want to elaborate on them.

As for wobble, this is another factor that varys not only with the
individual, but I think also with the speed you are riding. I'd
rather
not factor in wobble, unless it happens automatically as part of the
calibration method.

That is stinky. That way you will have wobble in some data but not in
others, depending on how it happened to have been measured.
Contamination of the data set!

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


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Klaas Bil - Newsgroup Addict
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Cokerhead writes:

OK,
Here's my scientific method. I stole data from other people. I entered
it into my computer. I adjusted from time to time, based on
observations from other road markings and bicyclists and car odometers. I
am happy to get within 2% accuracy(I usually ere on the fast/long side).
I give myself a break and don't try to discount for wobble(I don't wobble
as much as some)
To add to Mark's methods, here is what I do:
I rode over a 'measured mile' on a bike path and counted the revs, getting
about 577. I made sure the cycle computer gibed with that. This takes into
account the wobble of my riding. Here are the calcs:
Wheel height: 35.75"
Theoretical revs per mile [5280/(35.75 x pi)] = 564
Actual revs per measured mile: 577
Wobble effect: 2.3% (I ride an extra 23 feet for every thousand revs)
This means I'm riding an extra 115' or so every mile.

If you factor your measured mile (revs per mile) into the cycle computer,
you get a truer idea of your actual speed than if you just go by
circumference.

Now to answer the questions:
A:230-245lbs(lately)
190-195

B:45-50psi
50-55psi

C:Varies from ride to ride

I did a rollout(unloaded) long ago and don't remember the number
Right now I have 281 entered into my cyclometer and I'm happy with that
number.
I can't recall the # I entered. It's certainly around that one.

-Mark
David

2776mm
A. rider weight 170 lb
B tyre pressure 50 psi
C tread wear (as an estimated percentage) 50
3) from a ridden distance so that wobble is included. Distance is 3
revolutions, averaged over multiple runs

---Nathan

2782 mm
calibrated via 0 UPD known distance 2.65 mile ride


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duaner wrote:
*2782 mm
calibrated via 0 UPD known distance 2.65 mile ride *


FYI: that's with the tire at 32psi and moderately warn down (about 1/2
of it's life), and I weigh 150lbs


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Can't remember the exact figure I used, but my view is that a 1/2 inch
error on a 36 inch diameter = 1.3%. That's more accurate than my car
speedo or scooter speedo. My weight fluctuates; the weight of water in
my Camelbak fluctuates; the tyre pressure varies throughout a ride. I
reckon if the tyre's a bit softer, then the mileage and speed are
'rounded up', but pedalling is a bit harder, so it's self-compensating.
Then again, I only use the computer for comparing my own performances.


--
Mikefule - Roland Hope School of Unicycling

Why does no one shout, "Where are your steering head bearings,
derailleur mechanism and your other inner tube?"?
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These rollout posts are fragmented and I don't want my post to get lost;
it's in 'this thread' (http://tinyurl.com/mru8).

Basically I argue in detail for eliminating all rider characteristics
from the rollout that we share.


--
U-Turn - Mounting a Revolution

Weep in the dojo... laugh in the battlefield.

'Strongest Coker Wheel in the World'
(http://www.unicyclist.com/gallery/albup39)

-- Dave Stockton
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-Originally posted by johnfoss-

Because we are the nerds, not them.


Very well placed post, John! We can get pretty nerdy over a millimeter
or two sometimes.

For my 2 cents worth on the rollout though...when i first fitted a
computer to my coker, i did an unmounted rollout...just pushed it down
the road and took a measurement. I knew it wouldn't be very accurate,
but i couldn't figure out any way to do an accurate rollout mounted.
Then i spent several days making small adjustments after riding on
routes of "known" distances until the computer reading matched what i
thought the distance was.

Not very scientific, i know...you've still got the argument of "how did
you arrive at the known distance?"

Anyway, the number i arrived at was 280...my cheapo computer only
accepts cm, not mm.

_______________

A man with a watch always knows what time it is... a man with two
watches is never quite sure.


--
Chuck Webb


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

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On Tue, 9 Sep 2003 11:38:07 -0500, U-Turn
wrote:

Comments?
First of all, I respect your opinion which you have so carefully
phrased. Thanks a lot! From the data that people post I hope to be
able to assess a typical (or 'best') Uncalibrated Rollout. And I will
include that number as a key result. Only I don't like the name.
Uncalibrated sounds as if no care has gone into it, e.g. you just take
the nominal 36" and multiply by pi. I'll try and think of another
name.

He or she can easily determine a single
multiplier that takes into account of wobble, weight, typical tire
pressure, etc.. Call this multiplier the -RCF-, or *Rider's
Characteristics Factor*.
I wouldn't say that the effects of wobble, weight etc can /easily/ be
determined. Indeed, that is precisely what this little project is
about. But I like your way of reasoning and ideally the results of my
endeavour should include the Uncalibrated Rollout (by whatever name)
and a formula that calculates an estimated RFC from the parameters
mentioned in my 'original' post.

I won't have time, BTW, to do the math until after next weekend.

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