Translating “La vita è come una bicicletta con dieci rapporti... Tutti noi abbiamo rotelline che non usiamo mai”

Question

I don't understand the meaning of rapporti and rotelline here... clearly the second one is not tires.

Can someone explain to me the specific meaning or translation of these two words?

Answer 1

The sentence refers to a 10-speed bicycle, where you are unlikely to use all possible speeds.

More specifically, rapporto means here “speed” or “gear”, or literally “ratio”, because in a bike different speeds correspond to different ratios (turns of the pedals) / (turns of the rear wheel). In a car, for comparison, you'd say marcia. (The Italian word rapporto has a number of other meanings not referred to here, including “report” and “relationship”.)

And rotelline (literally, “small wheels”) refers to the sprocket wheels of the shift mechanism.