My 2nd guni model (finally complete except for paint and brake caliper) is a slight refinement of Purple Phaze. Improvements are a modified frame, allowing a narrower jackshaft and jackshaft housing. This leaves room for an 80mm hub flange width, plenty for the 36". Phaze Too has better changeability of gear ratios, as it uses standard bike 58BCD granny rings. Ratios are: 20t = 1.00, 22t = 1.22, 24t = 1.44, 26t = 1.67, and 28t = 1.96. Although this is still a fixed gear machine, the chainrings permit up to 5 choices of gear ratios on one jackshaft. Gearing is changed by switching out the chainrings on the right crank and inboard jackshaft.
The hub is a custom Tommi Miller, 135mm bearing width, 100mm flange diameter, 80mm flange width, and 35mm hub bearings. The hub is drilled on both sides for ISO disc brake pattern (6 x 44BCD), so it uses a disc brake on the left side. More reports when I add the brake caliper.
This is a very impressive guni you put together.
I was wondering if it was possible at all to make a geared uni with a chainig system where you can change gears on the fly, any ideas ?
I know that the Sclumpf can switch between 1 and 1.5 as you ride, but I think the future lays in chaining systems for their price and versatility (5 gears in this case). This is why I would be psyched if anyone came up with a uni like yours that can somehow be changed as you ride.
This would be extremely difficult, as shifting gears requires slack in the chain, and in general, slack chains on unicycles are Bad Things. What one might be able to do is engineer a CVT - Continuously Variable Transmission. That would be quite the beast to learn to ride.
It’s officially available for loan in Seattle, although I hereby impress a legal, equitable, and manufacturing lien on it, forecloseable with dire consequences! Current gear is 1.44 with 170mm cranks, so you guys oughtta be able to handle that…But good thing it’s not painted yet…