Joe Marshall
2001-10-04, 02:02 PM
I've just been thinking hard and I think I know what I want.
What I'd like for road riding is a Coker, with the nice wheel momentum
etc. maybe an upgraded rim, but with a simple planetary gear hub, to put
the speed up to 1.5x current speed ie. 56in equivalent. Annoyingly, it
would be much easier to gear down the speed as the sun gear could be on
the axle, whereas in the desired version, the axle has to drive either the
planet carrier, or the ring gear and the hub flanges have to attach to
either the sun gear or the planet carrier.
If that bit about gears doesn't make any sense see:-
http://psdam.mit.edu/2.000/vta/Transmission_Auto/planetary_gear_sets.htm
These gears are basically what sturmey-archer hubs are based on, but
removing all the variable transmission parts one could make a much simpler
version which I'd guess anyone competent enough to engineer a standard
bicycle hub would be able to make.
Something similar would be pretty cool attached to a 26in wheel for a fast
muni too. What would be the best thing ever would be one of these:-
http://www.schlumpf.ch/speed/speeddrivee.html altered to have hub flanges
and work properly backwards. This would fix every possible problem, giving
you 1:1 and 1.65:1 gears, which are switched by kicking a button on the
end of the axle. I don't suppose they do custom versions though.
Does anyone know someone with enough engineering stuff and time who could
make custom hubs?
cheers,
Joe
What I'd like for road riding is a Coker, with the nice wheel momentum
etc. maybe an upgraded rim, but with a simple planetary gear hub, to put
the speed up to 1.5x current speed ie. 56in equivalent. Annoyingly, it
would be much easier to gear down the speed as the sun gear could be on
the axle, whereas in the desired version, the axle has to drive either the
planet carrier, or the ring gear and the hub flanges have to attach to
either the sun gear or the planet carrier.
If that bit about gears doesn't make any sense see:-
http://psdam.mit.edu/2.000/vta/Transmission_Auto/planetary_gear_sets.htm
These gears are basically what sturmey-archer hubs are based on, but
removing all the variable transmission parts one could make a much simpler
version which I'd guess anyone competent enough to engineer a standard
bicycle hub would be able to make.
Something similar would be pretty cool attached to a 26in wheel for a fast
muni too. What would be the best thing ever would be one of these:-
http://www.schlumpf.ch/speed/speeddrivee.html altered to have hub flanges
and work properly backwards. This would fix every possible problem, giving
you 1:1 and 1.65:1 gears, which are switched by kicking a button on the
end of the axle. I don't suppose they do custom versions though.
Does anyone know someone with enough engineering stuff and time who could
make custom hubs?
cheers,
Joe