Abstract: A brake adjustment mechanism maintains a brake actuating piston (17) stroke within a preferred range compensating for brake wear by repositioning the piston along a deformable adjustment tube (33). The tube is deformed when excessive piston travel draws the tube along a tube expanding member (51). Adjustment mechanism stresses are minimized by insuring the annular regions of contact between the outer surface (59) of the expanding member (51) and the tube (33) as well as between the inner surface (57) of the expanding member (51) and an expanding member retaining groove (55) in a cantilevered pin (49) are smooth lacking both sharp corners and flat regions. The expanding member (typically a split ring) engaging the deformable tube along an annular surface (59) of the tube and also engages the annular groove along an annular surface (55) of the pin groove. Normals (63) to the deformable tube surface are more nearly orthogonal to the pin axis (43) than normals (61) to the pin groove annular surface.

Abstract: A brake adjustment mechanism maintains a brake actuating piston (17) stroke within a preferred range compensating for brake wear by repositioning the piston along a deformable adjustment tube (33). The tube is deformed when excessive piston travel draws the tube along a tube expanding member (51). Adjustment mechanism stresses are minimized by insuring the annular regions of contact between the outer surface (59) of the expanding member (51) and the tube (33) as well as between the inner surface (57) of the expanding member (51) and an expanding member retaining groove (55) in a cantilevered pin (49) are smooth lacking both sharp corners and flat regions. The expanding member (typically a split ring) engaging the deformable tube along an annular surface (59) of the tube and also engages the annular groove along an annular surface (55) of the pin groove. Normals (63) to the deformable tube surface are more nearly orthogonal to the pin axis (43) than normals (61) to the pin groove annular surface.

Abstract: A wheel (11) having a rim (12) with a pair of flanges (17, 19) including a peripheral potential roll surface (33) on at least one flange for contacting the ground in the event of tire failure has a convexly contoured roll surface with a finite cross-sectional radius of curvature (42) at the outermost radius of the wheel to provide an optimized shape of the contact surface and an enhanced contact area without introducing any flat regions in the contact area. The roll surface is formed to have a finite radius of curvature throughout the potential roll surface. The roll surface radius of curvature and may be formed in cross-section as a central circular segment (40) blending smoothly into two circular segments (44, 50) of lesser radii at the central circular segment extremities, or may be formed in cross-section as a portion of an ellipse (57) having a semi-minor axis (63) extending generally radially along the respective annular rim portion.