A suspension system, particularly for a pedal-driven vehicle, comprising a telescoping strut having first and second telescopingly and coaxially engaged members, and having a damping system comprising a damping fluid, a damping piston connected to a piston rod, an inertia-activated compression fluid flow control mechanism and a pressure-activated compression fluid flow control mechanism disposed in the first telescoping strut. The inertia-activated compression fluid flow control mechanism comprises a valve body biased by a valve spring into a first position over a radial groove formed on the piston so that the valve body prevents fluid flow through an inertia-activated compression fluid flow circuit in response to force inputs imparted to the vehicle frame. The valve spring and valve body are connected to the piston rod which extends into the first telescoping member and is attached to the vehicle wheel, such that the valve body may be moved into a second position permitting fluid flow through the inertia-activated compression fluid flow circuit by force inputs imparted to the vehicle wheel. Because the inertia-activated fluid flow control mechanism is inertia-activated and not pressure-activated, a force impact imparted to the vehicle wheel results and fluid flow through both the pressure-activated and inertia-activated flow circuits, whereas force inputs such as from pedalling, weight shifting and acceleraation or deceleration forces do not result in flow through the inertia-activated circuit. The suspension system therefore resists the absorption of pedal drive energy, provides a ride-leveling effect, and provides a broad range over which the damping system may be adjusted.