a flywheel is a large heavy wheel shaped object used to store energy... your front gears are chainrings. 53-12 is unrealistic on the flats at a fast cadence for anybody who isn't named tom boonen. even then, you'll see cat1 pros using a gear like 53-16 and spinning at a faster cadence. I spend a lot of time in the 52-15 to 52-17 range.