Re: Giraffe chain question (tight spot in chain)
It should be, but a bend ‘in the seat post’ as you said shouldn’t change this. Your frame would have to be bent in the area between the wheel and bottom bracket (crank barrel). I think some giraffes are built with a little bit of offset in the chain. This is probably okay to a certain point. Deraileur bikes run on offset cogs.
In any case, the loose-tight problem isn’t because your chain is out of line, because that should be constant. As Harper and Sem said, in unicycle parts, there is usually some degree of off-centeredness of the center hole in either the top or bottom cog (or both). It only takes a tiny deviation for this to be noticeable with the tightness of chain we use on giraffes. On a bike you don’t need so much tension, and giraffe unicycles are usually made from cheap bike parts, not the fancy stuff.
If your loose-tight cycle is consistent with rotations of either cog, that’s your problem. It could also be a combination of both cogs being at a certain orientation, if your ratio is not 1:1 and both cogs are off-center.
If your chain is old or has tight links, it might be a good time to replace it. Nobody wants their giraffe chain to break. You can land really badly in a giraffe dismount when there’s no warning.
That’s what you have to do. It’s okay if the chain is a little loose, but it should never come off. You need enough tension that it will stay on even under high torque, such as catching your balance or hard idling. Too tight, though it causes wear & tear, is better than too loose. My Schwinn Giraffe chain also cycles loose to tight, but within acceptable limits.
Oddly some early multi-wheelers had chain drives. The Bill Jenack collection included a three-wheeler that Steve McPeak used to use in shows. There was a chain hidden inside the two-tube frame. This gave him a safer ride, so he didn’t have to worry about tire pressure vs. friction every time he rode it.
3 wheelers do not ride like giraffes of equivalent height. They are much heavier, which makes them more sluggish. They fall a lot harder, which makes them more likely to bend cranks or otherwise get damaged after a while. And you have to constantly monitor tire pressure to assure enough traction. A “safe” amount of traction on a 3 wheeler makes for a drivetrain with a fair amount of friction in it.
But at least you can walk the wheel up there…