Ever thought why they say a bike is 18, 21, 27 speed? I think it is incorrect. Well the mathematically it is…. 2X9=18, 3X7=21, ect. But in reality we have something called “wrong gear”. Eventually we can’t use all the gears provided and so it’s not 18, 21 or 27 speed bike anymore. Am I right or I’m missing something out?