Chimera Grom Brembo P34 Rear Brake Caliper Bracket upgrade is a popular modification for Grom motorcycles that allows the installation of a Brembo P32 or P34 rear brake caliper. The Brembo P32 and P34 caliper is a high-performance brake caliper commonly used in racing applications, and upgrading to this caliper can improve braking performance on the Grom.