This invention provides a stabilizing system and method for two-wheeled vehicles that affords the rider no restriction on the full range of movements (banks, leans, etc.), while providing greater stability during turns and other maneuvers so that an unintentional bank or tilt (potentially causing a fall) is less likely, even at slow speeds and startup. A rotating mass of predetermined mass-value and radial mass-distribution is provided coaxially with the front axle. The mass is supported on bearings and freewheels with respect to the rotation of the front wheel. It can be induced to spin significantly faster than the front wheel thereby generating a gyroscopic effect at the front wheel about the axle. The gyroscopic effect limits the rider's ability to execute excessive steering, thereby preventing jackknife movements. The mass can be an electric-motor-driven flywheel within a shell housing that includes a drive tire battery, control system and drive motor.