Originally Posted by
merlinextraligh
Take a look at this.
http://www.gear-calculator.com/#
When we talk about gear ratios, its easier to talk about them as the number of teeth on the front chainring, and the number of teeth on the rear cog, such as 53/12 or 39/23.
It's not useful to talk about 3-2, or 3-5 because we don't know the size of your third chainring (which I'm assuming your referring to the outside big ring) or your fifth cog (or even whcih direction your counting from).
+1. Merlin is absolutely right. It is remarkable how many novices (including moi lo these three decades ago) start out thinking that you talk about bike gears like car gears, by some order that you would use to identify them or move through them. As Merlin says, there is not enough standardization to make that practical. With experience most folks just say the number of teeth front and rear as in 32/12 or some such.