[Water Warrior 2]

Let me try for a bit of input. The bike sprockets and chain would be in a similar category as the rear end(differential in a cage) or the transaxle in a front wheel drive cage. My cage has a 4.11 to 1.0 rear end ratio. The drive shaft turns 4.11 times for every turn of the axle. Just to muddy the waters now we go to the internal gearing of the transmission in a bike. The GZ has 5 gear ratios that we can relate to during every ride and shift. There is also another set of internal gears and their ratio. There is another gear on the shaft(along with the 5 gears)that drives a gear mounted on the output shaft that we all recognize as the front sprocket shaft. The driven gear and it's drive gear also have a ratio sometimes referred to as an internal gear ratio. All in all it is a numbers game and best left to the designers for the best compromise in power, speed and reliability of a given machine.
Now I will sit back with a coffee and try to understand what I just said. lol.