> I was reading in catch (the british juggling mag) that there was on display a > 3 speed unicycle at the british convention in Manchester. I was wondering if > anybody had had a go on it, or anything similar, and what was it like. I > suspect that it would be hellish when changing gears- is it easier to change > the gears while idling or is it better when going forwards (or backwards?). > > GAV >
How the hell do the mechanics work on that?! I can’t even imagine how it would
fit. Where would you have the gear changer lever? What sort of gear mechanism
would you have?
I was reading in catch (the british juggling mag) that there was on display a 3
speed unicycle at the british convention in Manchester. I was wondering if
anybody had had a go on it, or anything similar, and what was it like. I suspect
that it would be hellish when changing gears- is it easier to change the gears
while idling or is it better when going forwards (or backwards?).
Better yet, I know Bob Knight who built it. I haven’t had the opportunity to
have a go on it (I haven’t really got the hang of giraffes yet - severe lack of
people prepared to lend me theirs to practise on).
I can assure you that it’s no problem to change gear. Bob can shift up and down
happily while going forward or idling, or probably backwards, knowing him. As I
understand it, the only requirement is that one reduce the pedal pressure during
a shift, but then as anyone (like me) who rides a two-wheeler with a Sturmey hub
knows, that applies to normal bikes and isn’t a problem unless one is really
standing on the pedals.
Just in case it isn’t clear from the photo, this beast uses a fixed Sturmey
Archer 3 speed hub not a derailleur (it’s surprising how many people assume
that the derailleur is the only possible cycle gear shift). The hub itself is
an antique (early 1950s I think), probably worth more than the rest of the
unicycle (which was made by Bob and his dad). The equivalent wheel sizes are
20", 24" and 28".
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. —
>I was reading in catch (the british juggling mag) that there was on display a 3 >speed unicycle at the british convention in Manchester. I was wondering if >anybody had had a go on it, or anything similar, and what was it like. I >suspect that it would be hellish when changing gears- is it easier to change >the gears while idling or is it better when going forwards (or backwards?). > >GAV
I suspect (although I have no evidence) that you would have to stall, with
little or no force on the pedals before changine gear. I think it was built with
a sturmey archer hub, which usually changes better with no load. The downer is
that those hubs are notorious for changing into neutral is you dont get the
lever neatly into its notch or under heavy load, and I dont fancy a giraffe that
starts to freewheel when the going gets tough.
I figured out how you could get derailleur gears to work once - allowing up to
24 gears, but I havnt had a chance to try to build such a contraption.
Anyone got ideas for making a geared unicycle that isnt a giraffe - rather more
practical for use commuting etc.?
3 speeds - by disabling the freewheel on the sturmey hub? The epicyclic gears
should still work backwards. What about the more recent sturmey 5 speed hub -
(and does anyone know how they work - they have 2 independent control cables)
Derailleurs - how do people propose to keep tension both ways ? - springs are
going to be an awful lot weaker than legs, which will lead to lags going
backwards. unless 2 opposing sets are used which then gets horribly fat,
complicated (and possibly interesting if 2 different gears are selected…)
>Derailleurs - how do people propose to keep tension both ways ? - springs >are going to be an awful lot weaker than legs, which will lead to lags >going backwards. unless 2 opposing sets are used which then gets horribly >fat, complicated (and possibly interesting if 2 different gears are >selected…) Clive
I was thinking of the fat, complicated approach:- two derailleur freewheels on
opposite sides. Like you say, you could have different gears for forwards and
reverse. Idling makes you go forwards. I never claimed engineering simplicity,
but it could be very strange to ride.