Alo:
Does your bike have 20" wheels?: BF Mothership suggestd a 20" wheel factor--because I have 20" wheels.
Is the computer set up for 26" wheels? Since it was old but pefect condition It wasn't set up at all, but of course I could program it for various sizes ... but not down to 20".
Do [I} want to know the difference in circumference?: No, I want to know "the wheel factor ... number" that gets programmed into the computer that translates wheel revolutions into speed/distance, that's appropriate for 20" wheels. Maybe that's just the circumference, I don't know.
Or is it something else? YES. I want to try to avoid the measuring and math. Surely someone with 20" wheels can tell me what number they programmed into their computer ... and that should get me close.
But if not, I'll dig through Juan's and Moe's resources and get out my tape measure.