Pandora

General
1

David,
Don’t complain to your wife that she isn’t the other woman you used to
date. Pandora is not Coker, and I don’t think she should try to be. Even if
Coker were lots better, I see Pandora as FANTASTIC and NEEDED. The speed
differences will be easily overcome with a higher gear ratio (We both said it
should be 2X, to ride like a 48" tire). It will definitely beat Coker then.
It may require better padding & helmet, but that’ goes with speed.
Other benefits: You can’t take a Coker on the train in Europe (and
may have to pay more to fly her in the USA), but Pandora travels easily.
I think you’ll also get better at falling safely off of her, and you
probably are already after trying one-foot repeatedly. We need to learn the
idiosyncracies of any uni to handle the falls.
We need Pandora!!!
PS Tell him not to seal the bottom of the seat post tube to give an
additional inch of flexibility with long seat posts.
Bill

2

Doctormacorni,

I have added you to my smart guy list. Prior to the above post Harper was the only person on it. Now there is two.

Great post–you are one smart dude!

dan

3

Re: Pandora

On Wed, 15 May 2002 21:46:52 EDT, Doctormacaroni@aol.com wrote:

>The speed
>differences will be easily overcome with a higher gear ratio (We both said it
>should be 2X, to ride like a 48" tire).

Someone correct me if I’m wrong but I think 2X is impossible for an
epicyclic hub, unless it would have two stages and get very
complicated.

Klaas Bil

“To trigger/fool/saturate/overload Echelon, the following has been picked automagically from a database:”
“SWAT, Richard Reid, CCSC”

4

Re: Re: Pandora

The no-longer produced Sachs Elan 12 speed internally geared bicycle hub’s top 3 gear ratios are 2.061, 2.217 and 2.364. The Schlumpf Mountain Drive has a 2.5:1 reduction, and is single stage.
I think one of the key interests here is the epicyclic hub’s reduction of revs per mile. I only want to go so fast on a uni. If I’m in a hurry, I’ll ride my bike or drive. But, the ability to go farther on my uni with fewer revs, and do it on high end tires and wheels I can get at my LBS, is very appealing.

5

Re: Re: Pandora

Klaas-

You are correct. The theoretical limit for a simple planetary gear train is 2:1. In this case, the sun gear and ring gear are the same size and the planet gears approach zero radius, clearly impossible to build. A more realistic upper limit would be 1.7:1.

Gear ratios higher than this require a compound system in which a two (or more) gear cluster replaces each planet gear.

A reduction stage is not the goal here. Also, the gear train is connected differently for a unicycle due to drive constraints.