BRAKING® EPR146R Braking Disc Epta Stage 0-330mm (right)AL7075 hard oxidized aluminum hub (30m) Induction hardened steel track Thickness 5. 8 mm Controlled flotation of EPTA discs, with ventilated grooves to ensure better cooling of the interface area. Optimized lightening to avoid the onset of vibrations 3mm thick straight section ridges on the outer side of the Wave profile form a heat dissipation area that is not in contact with the pads but has greater thermal inertia than the rest of the disc. The