Abstract: A wheelchair (10) comprises a seat member (14) pivotally mounted on support beam (16) of a chassis (12). The chassis (12) includes a pair of spaced-apart side elements (18), each depending from the support beam (16) and having a first part (20) supporting a front ground-engaging wheel (22) and a second part (24) supporting a rear ground-engaging wheel (26). A bracing member (32) extends between the second parts (24) of the side elements (18), and supports a variable length strut (68). The variable length strut (68) extends from the bracing member (32) to rearward part (66) of seat member (14) and controls pivotal movement of seat member (14) around support beam (16).