Originally Posted by
cyccommute
Four of my current bikes have 20 tooth inner rings. I have had 18 tooth inners and a 16 tooth inner with a Quad adapter.
Along such line, I currently have 18T on my main full-size bike, for 1.24m of development, and in reserve 16T. However, on the main folder I have 20T that yields even lower 1.06m with all the rest I have there. The simple justification is that I take the folder into more challenging places than around home.