Abstract: A brake disc for a high performance vehicle comprises a rotor 20 formed of grey cast iron and comprising a friction ring 24 annular about an axis of rotation 26 and, coaxial with the friction ring 24, a tubular flange 28 extending axially from the friction ring 24 to a free end 28a and having a wall 28e with a radially inner face 28c and a radially outer face 28d. A hub 22 formed of aluminum is cast over the flange 28 to encapsulate at least a portion of the wall 28e, with which it has a shrink-fit connection. The encapsulated portion of the wall is made smooth (or otherwise formed with a varying radial dimension, or a screw thread) so as to permit differential thermal contraction, in an axial direction, of the hub 22 relative to the flange 28 as the hub 22 solidifies and cools after its casting. By this means, retained stresses in the hub 22 are minimized.

Abstract: A brake disc for a high performance vehicle comprises a rotor 20 formed of grey cast iron and comprising a friction ring 24 annular about an axis of rotation 26 and, coaxial with the friction ring 24, a tubular flange 28 extending axially from the friction ring 24 to a free end 28a and having a wall 28e with a radially inner face 28c and a radially outer face 28d. A hub 22 formed of aluminium is cast over the flange 28 to encapsulate at least a portion of the wall 28e, with which it has a shrink-fit connection. The encapsulated portion of the wall is made smooth (or otherwise formed with a varying radial dimension, or a screw thread) so as to permit differential thermal contraction, in an axial direction, of the hub 22 relative to the flange 28 as the hub 22 solidifies and cools after its casting. By this means, retained stresses in the hub 22 are minimised.