A boot seal for a joint assembly (30, 32, 62, 64, 66, 68) connecting first and second machine components (24, 26, 28, 42, 52, 54, 56) pivotable relative to one another in a finite angular pivoting range, the boot seal comprising: a resilient seal body defining a center axis and including a body wall extending between a first axial body end and a second axial body end and circumferentially around the center axis; the first axial body end defining a larger diameter circular opening and the second axial body end defining a smaller diameter circular opening; a first sealing ring positioned at the first axial body end and including an exposed outer radial surface positionable in radial contact with the first machine component (24, 26, 28, 42, 52, 54, 56); a second sealing ring positioned at the second axial body end and having an exposed outer axial surface positionable in axial contact with the second machine component (24, 26, 28, 42, 52, 54, 56); and the resilient seal body further defining an axial body length, and being in a rest configuration where the body wall forms a curvilinear taper extending a majority of the axial body length from the first to the second axial body end (106, 108), and the resilient seal body being deformable in response to axial compression between the first and second machine components (24, 26, 28, 42, 52, 54, 56) to a squished configuration where the body wall forms a radially outward bulge storing an energy of the axial compression to bias the second sealing ring against the second machine component (24, 26, 28, 42, 52, 54, 56), characterised in that the body wall further includes a longer wall section adjacent the first axial body end, a shorter wall section adjacent the second axial body end, and an outer wall surface having a convex axial profile within the longer wall section and a concave axial profile within the shorter wall section; and in that the body wall further includes an inner wall surface having a concave axial profile within the longer wall section, and a convex axial profile within the shorter wall section. a resilient seal body defining a center axis and including a body wall extending between a first axial body end and a second axial body end and circumferentially around the center axis; the first axial body end defining a larger diameter circular opening and the second axial body end defining a smaller diameter circular opening; a first sealing ring positioned at the first axial body end and including an exposed outer radial surface positionable in radial contact with the first machine component (24, 26, 28, 42, 52, 54, 56); a second sealing ring positioned at the second axial body end and having an exposed outer axial surface positionable in axial contact with the second machine component (24, 26, 28, 42, 52, 54, 56); and the resilient seal body further defining an axial body length, and being in a rest configuration where the body wall forms a curvilinear taper extending a majority of the axial body length from the first to the second axial body end (106, 108), and the resilient seal body being deformable in response to axial compression between the first and second machine components (24, 26, 28, 42, 52, 54, 56) to a squished configuration where the body wall forms a radially outward bulge storing an energy of the axial compression to bias the second sealing ring against the second machine component (24, 26, 28, 42, 52, 54, 56), characterised in that the body wall further includes a longer wall section adjacent the first axial body end, a shorter wall section adjacent the second axial body end, and an outer wall surface having a convex axial profile within the longer wall section and a concave axial profile within the shorter wall section; and in that the body wall further includes an inner wall surface having a concave axial profile within the longer wall section, and a convex axial profile within the shorter wall section.