An attachment for a wheelchair includes a secondary front-wheel pair that is movable from a disengaged up position, to a deployed down position, and back again. In the disengaged up position, the secondary front wheels are up off the ground, so the primary front wheels of the wheelchair are in contact with the ground and thereby being used. In the deployed down position, the secondary front wheels are down in contact with the ground and are thereby being used, so the primary front wheels are now removed from contact with the ground and are no longer in use. In typical embodiments, the secondary front wheels are relatively larger wheels for traversing rough terrain, the primary front wheels are relatively smaller wheels for traversing smooth terrain, and the secondary front wheels move between the disengaged up position and the deployed down position in a pivoting motion.