The present invention relates to a curb climbing system for a wheelchair having a pair of rear larger drive wheels, a pair of small caster wheels, and a static hand grip for a caregiver being located at a back region behind an occupant seat; the system comprises: (1) a rear rollover-climb lever mechanically linked to a pivot to permit the caregiver located at the back-end region of the wheelchair to apply a downwards forceful thrust sufficient to shift the lever from an upward-position to a downward-position; and (2) a mechanical torque engagement system to translate the downwards forceful thrust to a rollover rotation torque around a pivot point on a stair-like curb, to climb over the stair-like curb. During climb procedure, a ratchet system provides unidirectional backwards rotation of the rear wheel pair and prevents forward rotation to block the wheelchair from rolling down the stairs for safety.