Based on gear ratio, GAIN RATIO has a further consideration combining the power generated through pedaling. It includes the crank length and the radius of rear wheel, which are levers, to calculate the power delivered by drivetrain system. By applying GAIN RATIO, cyclists could estimate and compare their athletic performance on different types of bikes and transmissions.
Gain Ratio would be calculated as: (Rear wheel radius / crank length) x (front chainring / rear sprocket), which is the ratio of the distance travelled by bike to the distance pedal rotates.
GAIN RATIO literally means how far the bike will move after how hard you pedal. Pedaling on two bikes with same crank length but different bike gears, those two would move with varying distance. In contrast, if the crank length is the only variable, the rate of depletion of stamina and the degree of fatigue accumulation when riding on those two bikes would not be the same. Therefore, whether you are training to increase your bike power, or choosing suitable drive train to improve leverage, gain ratio is applicable for matching your power output with the perfect bike.
Compared to the existing bike gear measuring systems, such as Gear Ratio, Gear Inches, and Meters of Development, GAIN RATIO not only focuses on the ratio of gears, but combines kinetic perspective, which considers the influence of levers (crank length and wheel radius) on leverage for the drive train. The theory proposes to center on cyclist's physical fitness to setup the drivetrain rather than simply looks for the ideal gear ratio. If power calculation is included, cyclists could estimate and compare their athletic performance on different categories of bikes and transmission. Simply put, GAIN RATIO is a more universal and intuitive system to choose right gear ratios.