# cangaroo

Hi all, I’m about to buy a cangaroo but don’t know what value I should choose
for the distance between the center of the wheel and the axis. It’s called
excentricity (translated from German), I don’t know if it’s the proper word in
English. I want a big distance but without affecting the stability of the
unicycle! Please anyone give me some hints or experience in that matter Chris

RE: cangaroo

> I’m about to buy a cangaroo but don’t know what value I should choose for the
> distance between the center of the wheel and the axis. It’s called
> excentricity (translated from German), I don’t know if it’s the proper word in
> English. I want a big distance but without affecting the stability of the
> unicycle!

Any movement from the center of the wheel will affect the stability of your
ride. What you probably want is enough to be obvious to an audience, while
keeping it relatively easy to ride. If you go too far, you might have troubles
with your feet hitting the ground, and just too big of a “lump” to ride over
with each turn.

You can use this picture as an example:
http://www.unicycling.com/unifoss/garage/kangaroo.htm Sorry it’s not too big,
but that’s a 20" wheel and you can get an idea of how far off center it is. It
looks like about 2" or so. The kangaroo in the picture was very visual to ride,
and was a good bit of work to pedal. I wouldn’t go any farther than that.

Notice how the pedals are on the widest side of the wheel. This helps you push
up the “uphill” part of the stroke, plus keeps your feet (or pedals) from
scraping the ground.

Enjoy, John Foss, the Uni-Cyclone (reply to jfoss@unicycling.com)
http://www.unicycling.com

“I meant to do that.” – Pee Wee Herman, after crashing his bike

Re: cangaroo

Hello

I have tried all the excentricity of the wheel exept excentricity =0

The excentricity =0 is possible I have see that at Unicon 9 It is a standard
unicycle with the cranks in the same direction

The easiest excentricity is a small (distance between the center of the wheel
and the axis = 3 cm 1.2 inch ) with this kangaroo unicycle I have done 14 km (9
miles) in 3 hours .

I have make a more exentric kangaroo unicycle with a plywood whell and the axle
near the rim with long cranks. It is rideable but I can’t do more than 100
meters because my legs are not strong enough to do more.

The limit of exentrycity is the place for the axle ( the axle must not cut the
tyre or the rim and must not touch the floor ) The cranks lengh must be more
than twice the excentricity

For the stage with a short show it is possible to have a maximum of excentricity
For body building the kangaroo unicycle with a maximum of excentricity is a good
device. For a long parade the excentricity must be low.

The skills are the same with a kangaroo unicycle with low excentricity. With a
kangaroo unicycle with a maximum of excentricity there are new skills:
- sitting : when the kangaroo unicycle is in the lower
position it is a stable chair for resting
- idling : it is possible to do standard idling (with
the pedals in the lower possition ) or opposite idling
(with the pedals in the higher possition )

I will write a web page for kangaroo with pictures in a few days.

“Christian Rimpau” <chrisjug@rumms.uni-mannheim.de> a écrit dans le message
news: 38BE93BE.29A86EA3@rumms.uni-mannheim.de
> Hi all, I’m about to buy a cangaroo but don’t know what value I should choose
> for the distance between the center of the wheel and the axis. It’s called
> excentricity (translated from German), I don’t know if it’s the proper word in
> English. I want a big distance but without affecting the stability of the
> unicycle! Please anyone give me some hints or experience in that matter Chris

Re: cangaroo

>The limit of exentrycity is the place for the axle ( the axle must not cut the
>tyre or the rim and must not touch the floor ) The cranks lengh must be more
>than twice the excentricity

For a kangaroo unicycle, the position of the axle can actually be fixed at the
center of the wheel (or any other fixed position). The ecentricity can be
adjusted by varying the length of the crank arms. Assuming one has a range of
very short to very long crank arms to adjust the (effective) ecentricity.

For a standard ecentric unicycle, the position of the axle can also be fixed at
the center of the wheel. For example, to get an ecentricity of 10 cm, use a 115
cm R crank arm with a 135 cm L crank arm or visa versa. In general using a base
(average) 125 cm crank arm length, an ecentricity of X cm can be done with a
(125 - X) cm R crank arm and (125 + X) cm L crank arm.

The above assumes that the ecentricity of the wheel is parallel to the crank
arms. If the crank arms and ecentricity are to be perpendicular to each other,
the wheel itself must be made ecentric by offsetting the axle from the center of
the wheel.

For both the kangaroo and standard ecentric unicycles, each crank arm’s length
can be adjusted independent of the other for additional interesting effects. For
the standard ecentric unicycle in particular, such an additional biase favouring
one crank might actually be desirable.

Sincerely,

Ken Fuchs <kfuchs@winternet.com>

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