A mechanical steering system for a wheelchair to permit a user's foot to pivotably adjust a pair of caster wheels of the wheelchair is provided. The system includes a platform coupled to a frame of the wheelchair, a foot controller assembly pivotably mounted to the platform and having a foot plate to receive the user's foot and a rod coupled to the foot plate, a drag linkage member coupled to the rod of the foot controller assembly, and a pair of lever arm assemblies pivotably mounted to the drag linkage member, each lever arm assembly having a lever rod coupled to a fork member, the fork member being coupled to one of the caster wheels. Pivotable movement of the foot plate is transferred through the drag linkage member to permit both lever rods of the lever arm assemblies to pivot, thereby enabling simultaneous pivotal adjustments of the caster wheels.