3 Speed

On the subject of deralieur gears. Having a free wheel on each sidde of the hub
will give a ‘fixed wheel’. Tying each gear mech into one gear lever will enable
both mechs to be driven in sync. This is the problem though; while one chain is
being driven forwards (as if pedaling forward on a two wheeler) the other is
being driven backwards so it can’t change gear. As soon as you change
direction though it will try to change and if there is a substantial force on
the chain it will slip. I have been very close to building this uni but this
slip in the chain just after changing gear and direction stopped me. Has anyone
tried this and found it work?

Related question: Can anyone work out how to gear up a standard uni, with out
going to large diameter wheels or very short cranks? (A Sturmey archer gear can
be used to slow one down.)

UnRelated question: Is there a land speed record for a unicycle of any
gearing/design?

Alan Gregory

ajgregory@mh1.mcc.ac.uk umist2@hed.me.umist.ac.uk

Re: 3 Speed

> Related question: Can anyone work out how to gear up a standard uni, with out
> going to large diameter wheels or very short cranks? (A Sturmey archer gear
> can be used to slow one down.)

I reckon would be possible for an expert to build an epicyclic hub which could
be driven by pedals on the same axis as the wheel.

>
> UnRelated question: Is there a land speed record for a unicycle of any
> gearing/design?

Dunno. Bob K has a 26" wheel geared up 2:1 (56"), and he can cruise it at well
over 20 Mph. The only problem is finding space, and dismounting in a hurry! The
pedals are on stub axles hung just below the wheel bearings, and driven with
short chains (the sprockets almost touch).

Peter Lister Email: p.lister@cranfield.ac.uk Computer Centre, Cranfield
University Voice: +44 234 754200 ext 2828 Cranfield, Bedfordshire MK43 0AL UK
Fax: +44 234 750875 — 3-1, 2-1, 1-1. Probability factor of 1 to 1. We have
normality. —