A brake system comprising: a pressure plate defining a contact surface, wherein the pressure plate is configured to compress a disc stack of the brake system; and a piston configured to cause the pressure plate to compress the disc stack, the piston comprising: a piston body configured to translate along a piston axis; and a piston cap defining a cap face intersected by the piston axis and defining a perimeter around the piston axis, wherein the cap face defines an inner surface section intersected by the piston axis, an outer surface section adjacent the perimeter, and a medial surface section between the inner surface section and the outer surface section, wherein the piston body is configured to compress the cap face against the contact surface of the pressure plate to cause the pressure plate to compress the disc stack, characterized in that the medial surface section defines a convex surface defining a curvature, wherein the convex surface is configured to reduce the curvature when the piston body compresses the cap face against the contact surface, and wherein the piston cap is configured to deform such that the inner surface section and the medial surface section contact the contact surface when the piston body compresses the cap face against the contact surface. a pressure plate defining a contact surface, wherein the pressure plate is configured to compress a disc stack of the brake system; and a piston configured to cause the pressure plate to compress the disc stack, the piston comprising: a piston body configured to translate along a piston axis; and a piston cap defining a cap face intersected by the piston axis and defining a perimeter around the piston axis, wherein the cap face defines an inner surface section intersected by the piston axis, an outer surface section adjacent the perimeter, and a medial surface section between the inner surface section and the outer surface section, wherein the piston body is configured to compress the cap face against the contact surface of the pressure plate to cause the pressure plate to compress the disc stack, characterized in that the medial surface section defines a convex surface defining a curvature, wherein the convex surface is configured to reduce the curvature when the piston body compresses the cap face against the contact surface, and wherein the piston cap is configured to deform such that the inner surface section and the medial surface section contact the contact surface when the piston body compresses the cap face against the contact surface. a piston body configured to translate along a piston axis; and a piston cap defining a cap face intersected by the piston axis and defining a perimeter around the piston axis, wherein the cap face defines an inner surface section intersected by the piston axis, an outer surface section adjacent the perimeter, and a medial surface section between the inner surface section and the outer surface section, wherein the piston body is configured to compress the cap face against the contact surface of the pressure plate to cause the pressure plate to compress the disc stack, characterized in that the medial surface section defines a convex surface defining a curvature, wherein the convex surface is configured to reduce the curvature when the piston body compresses the cap face against the contact surface, and wherein the piston cap is configured to deform such that the inner surface section and the medial surface section contact the contact surface when the piston body compresses the cap face against the contact surface. wherein the cap face defines an inner surface section intersected by the piston axis, an outer surface section adjacent the perimeter, and a medial surface section between the inner surface section and the outer surface section, wherein the piston body is configured to compress the cap face against the contact surface of the pressure plate to cause the pressure plate to compress the disc stack, characterized in that the medial surface section defines a convex surface defining a curvature, wherein the convex surface is configured to reduce the curvature when the piston body compresses the cap face against the contact surface, and wherein the piston cap is configured to deform such that the inner surface section and the medial surface section contact the contact surface when the piston body compresses the cap face against the contact surface.