A foldable wheelchair frame assembly comprising: a pair of side frames (24, 124, 224, 324); a cross-bracing frame assembly (36, 136) coupling the side frames together for movement transversely between a spaced apart deployed position and a proximate folded position; and a link assembly (61, 161, 261, 361) mounted in the cross-bracing frame assembly (36, 136) in a position between at least one of the side frames (24, 124, 224, 324) and a remainder of the cross-bracing frame assembly (36, 136), the link assembly (61, 161, 261, 361) being formed for variation of the overall length of the link assembly (61, 161, 261, 361) in a direction extending transversely between the side frames (24, 124, 224, 324) to prevent forcing of the side frames (24, 124, 224, 324) into unparallel movement during movement of the side frames (24, 124, 224, 324) between the deployed position and the folded position; characterized in that: the link assembly (61, 161, 261, 361) is in an extended position when the side frames are in both the deployed position and the folded position; the link assembly (61, 161, 261, 361) is retracted relative to the extended position in a partially folded position between the deployed position and the folded position; and the link (61, 161, 261, 361) assembly further comprises a biasing member (72, 172) biasing the link assembly (61, 161, 261, 361) toward an the extended position so as to bias the link assembly to both the folded and the deployed positions of the side frames. a pair of side frames (24, 124, 224, 324); a cross-bracing frame assembly (36, 136) coupling the side frames together for movement transversely between a spaced apart deployed position and a proximate folded position; and a link assembly (61, 161, 261, 361) mounted in the cross-bracing frame assembly (36, 136) in a position between at least one of the side frames (24, 124, 224, 324) and a remainder of the cross-bracing frame assembly (36, 136), the link assembly (61, 161, 261, 361) being formed for variation of the overall length of the link assembly (61, 161, 261, 361) in a direction extending transversely between the side frames (24, 124, 224, 324) to prevent forcing of the side frames (24, 124, 224, 324) into unparallel movement during movement of the side frames (24, 124, 224, 324) between the deployed position and the folded position; characterized in that: the link assembly (61, 161, 261, 361) is in an extended position when the side frames are in both the deployed position and the folded position; the link assembly (61, 161, 261, 361) is retracted relative to the extended position in a partially folded position between the deployed position and the folded position; and the link (61, 161, 261, 361) assembly further comprises a biasing member (72, 172) biasing the link assembly (61, 161, 261, 361) toward an the extended position so as to bias the link assembly to both the folded and the deployed positions of the side frames. the link assembly (61, 161, 261, 361) is in an extended position when the side frames are in both the deployed position and the folded position; the link assembly (61, 161, 261, 361) is retracted relative to the extended position in a partially folded position between the deployed position and the folded position; and the link (61, 161, 261, 361) assembly further comprises a biasing member (72, 172) biasing the link assembly (61, 161, 261, 361) toward an the extended position so as to bias the link assembly to both the folded and the deployed positions of the side frames.