Fastest speed on a coker?

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


--
nathan - BIG rides: Muni & Coker
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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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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

GizmoDuck wrote:

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

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

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