This invention provides a stabilizing system and method for two-wheeled vehicles that affords the rider no restriction on the full range of movements common to bicycles, but that provides greater stability during turns and other maneuvers so that an unintentional bank or tilt is less likely, even at relatively slow speeds and startup. A rotating mass (162) of predetermined mass-value and radial mass- distribution is provided coaxially with the front axle (312). The mass is supported on bearings (320) so as to freewheel with respect to the rotation of the front wheel (130). As such it can be induced to spin significantly faster than the front wheel thereby generating a gyroscopic effect at the front wheel (130) about the axle (312). This gyroscopic effect influences the steering of the wheel by the rider. Due to precession, the wheel tends to follow any excessive bank by the bicycle, ensuring that the rider can "steer-out-of an unintended tilt or bank. Likewise, the gyroscopic effect limits the rider's ability to execute excessive steering, thereby preventing jackknife movements.