A split cylindrical clamp encloses inner ends of grip bars of a folding handlebar to hold the grip bars in a firm, stationary, and strong riding position. A single user gesture flips a clamp lever to loosen the split cylindrical clamp allows the grip bars to be slid outward and folded to a folded position. The split cylindrical clamp is then tightened with another single gesture, flipping the clamp lever in an opposite direction, locking the grip bars in the folded position. While locked in the folded position, the grip bars are entirely immobilized.