Ideal 2 speed transmission(high/low) gear ratio?

[mckutzy]

These last while being a bit bored at work and having more than enough time to space out for a moment...
It occurred to me if a mini bike was to have a two speed transmission, what should be ideally geared to.

6:1 is typically used as a rule of thumb, but after that its hasn't really, to my knowledge, been discussed about.
This discussion would more pertaining to the ability to shift on the fly, as opposed to a stop and go range box.

For argument sakes on flat ground, paved surfaces, 18-24" rear tire (this is what I have on mine, so shall be the example) and 6.5 clone.....

 

[itsid]

governed?

then it'd be relatively easy ..

engage 2000 - 3600 for first gear (add margin) and see what the second gear would have to be to drop rpms back to ~2000
So let's assume the 18" that's ~32mph @ 3600 rpm with 6:1
say 30 mph (margin remember ) @2000 rpm would require a 3.6:1 ratio.

something like that should be at least plausible

OH.. wait.. the Rupp two-speed trans... what was it's ratio ? 1:1 and 2:1 on the jackshaft (and whatever final it came with) right? *shrugs* don't remember

'sid