A heavy vehicle disc brake, the disc brake comprising: first and second brake pads for selectively contacting opposing inboard and outboard faces of a brake rotor respectively; a brake caliper for confining the first and second brake pads in at least an inboard-outboard direction; an actuation mechanism housed within the brake caliper for selectively bringing the brake pads into contact with the rotor; and first and second brake pad support structures for restraining the first and second brake pads in a circumferential direction respectively; wherein at least one of the first and second brake pads and the corresponding first and second support structures comprise complementary profiles on circumferential faces thereof arranged so as to permit the brake pad to be inserted into the mounting structure in a transverse direction of the pad and at an angle to the circumferential direction of the structure and then for the brake pad to be pivoted about a fixed centre of rotation when a circumferential surface of the brake pad is in contact with a complementary circumferential surface of the support structure to be brought into a fitted position in the support structure, wherein at least one brake pad comprises a first circumferential surface having a profile that defines a part circular segment of a first fixed radius for contact with a complementary first circumferential abutment surface, and a second circumferential surface, the second circumferential surface having a profile that defines a part circular segment of a second fixed radius, the second fixed radius being greater than the first fixed radius for contact with a complementary second circumferential abutment surface, wherein the second circumferential surface comprises a first portion and a second portion (277b"), wherein the first portion is substantially planar and is in in contact with a complementary planar portion of the circumferential surface of the support structure . first and second brake pads for selectively contacting opposing inboard and outboard faces of a brake rotor respectively; a brake caliper for confining the first and second brake pads in at least an inboard-outboard direction; an actuation mechanism housed within the brake caliper for selectively bringing the brake pads into contact with the rotor; and first and second brake pad support structures for restraining the first and second brake pads in a circumferential direction respectively; wherein at least one of the first and second brake pads and the corresponding first and second support structures comprise complementary profiles on circumferential faces thereof arranged so as to permit the brake pad to be inserted into the mounting structure in a transverse direction of the pad and at an angle to the circumferential direction of the structure and then for the brake pad to be pivoted about a fixed centre of rotation when a circumferential surface of the brake pad is in contact with a complementary circumferential surface of the support structure to be brought into a fitted position in the support structure, wherein at least one brake pad comprises a first circumferential surface having a profile that defines a part circular segment of a first fixed radius for contact with a complementary first circumferential abutment surface, and a second circumferential surface, the second circumferential surface having a profile that defines a part circular segment of a second fixed radius, the second fixed radius being greater than the first fixed radius for contact with a complementary second circumferential abutment surface, wherein the second circumferential surface comprises a first portion and a second portion (277b"), wherein the first portion is substantially planar and is in in contact with a complementary planar portion of the circumferential surface of the support structure . <EOS>