crank length vs. wheel diameter??

Something like this?

48 is about equal to 32 geared up.

I am planning to eventually build up a schlumpfable 48" so I added that to my chart.

Throwing a 32 in there fills the gap nicely eh?

And of course the chart is just a guideline. There are all sorts of other factors, like the fact that big wheels roll better than small wheels, big wheels have more momentum, the fact that I am scared of cranks shorter than 100mm… etc.