This complete flywheel assembly features an increase in inertia mass that smoothens the power delivery. This helps to get power to the ground and keep momentum up through corners and tricky sections, resulting in faster lap times and more race wins. Easy to install, allowing you the opportunity to change flywheels for different types of riding. Note: Flywheels are measured by inertia weights because the effect of the weight differs depending on where it is in relation to the center of the crank. So a 4 ounce and 6 ounce weight might have the same affect depending on where they are positioned in relation to the center of the crank.