In Internal Combustion Engines Flywheels have many uses in modern machinery. Probably the most common is to store rotational energy to help drive internal combustion engines. The engine spins a flywheel mounted at the crankshaft, which then helps maintain forward momentum as the rotational energy stored in the flywheel is re-transferred back to the crankshaft to help the vehicle maintain speed and, especially, torque. Automobile torque, which is a measure of rotational force, is mainly dependent on the size, location and rotational speed of the flywheel. Cars also use their flywheels to connect the transmission to the engine through the clutch. The spinning of the flywheel helps to stabilize the engine's rotational speed while the car changes gears and the transmission is disengaged.