An extendable mast assembly for a material handling vehicle, the extendable mast assembly comprising: a base mast having a first web connecting a first web first flange and a first web second flange, wherein the extendable mast assembly having a base mast bearing coupled to the base mast characterised by a base mast bumper coupled to the base mast; a vertically extendable mast having a second web connecting a second web first flange and a second web second flange; a vertically extendable mast bearing coupled to the vertically extendable mast; wherein the base mast bearing is in contact with at least one of the second web second flange and the second web, and the base mast bearing is spaced apart from the second web first flange defining a base mast bearing space between the base mast bearing and the second web first flange; wherein the vertically extendable mast bearing is in contact with at least one of the first web second flange and the first web, and the vertically extendable mast bearing is spaced apart from the first web first flange defining a vertically extendable mast bearing space between the vertically extendable mast bearing and the first web first flange; and wherein the base mast bumper maintains the base mast bearing space between the base mast bearing and the second web first flange, preferably further comprising: a vertically extendable mast bumper coupled to the vertically extendable mast; wherein the vertically extendable mast bumper is spaced apart from the first web first flange defining a vertically extendable mast bumper space between the vertically extendable mast bumper and the first web first flange, the vertically extendable mast bearing space being larger than the vertically extendable mast bumper space; and wherein the vertically extendable mast bumper maintains the vertically extendable mast bearing space between the vertically extendable mast bearing and the first web first flange; and preferably the base mast bearing is canted and the base mast bumper is parallel to the first web. a base mast having a first web connecting a first web first flange and a first web second flange, wherein the extendable mast assembly having a base mast bearing coupled to the base mast characterised by a base mast bumper coupled to the base mast; a vertically extendable mast having a second web connecting a second web first flange and a second web second flange; a vertically extendable mast bearing coupled to the vertically extendable mast; wherein the base mast bearing is in contact with at least one of the second web second flange and the second web, and the base mast bearing is spaced apart from the second web first flange defining a base mast bearing space between the base mast bearing and the second web first flange; wherein the vertically extendable mast bearing is in contact with at least one of the first web second flange and the first web, and the vertically extendable mast bearing is spaced apart from the first web first flange defining a vertically extendable mast bearing space between the vertically extendable mast bearing and the first web first flange; and wherein the base mast bumper maintains the base mast bearing space between the base mast bearing and the second web first flange, preferably further comprising: a vertically extendable mast bumper coupled to the vertically extendable mast; wherein the vertically extendable mast bumper is spaced apart from the first web first flange defining a vertically extendable mast bumper space between the vertically extendable mast bumper and the first web first flange, the vertically extendable mast bearing space being larger than the vertically extendable mast bumper space; and wherein the vertically extendable mast bumper maintains the vertically extendable mast bearing space between the vertically extendable mast bearing and the first web first flange; and preferably the base mast bearing is canted and the base mast bumper is parallel to the first web. a vertically extendable mast bumper coupled to the vertically extendable mast; wherein the vertically extendable mast bumper is spaced apart from the first web first flange defining a vertically extendable mast bumper space between the vertically extendable mast bumper and the first web first flange, the vertically extendable mast bearing space being larger than the vertically extendable mast bumper space; and wherein the vertically extendable mast bumper maintains the vertically extendable mast bearing space between the vertically extendable mast bearing and the first web first flange; and preferably the base mast bearing is canted and the base mast bumper is parallel to the first web.