Excessive heat can cause resins in your brake pads to vaporize or "outgas." As the brake pads wear, the used friction material turns into a fine dust. This boundary layer of heat, gas, and dust builds up between the pad and rotor surfaces and inhibits performance.
The slots in StopTech Sport Slotted Brake Rotors are machined into the rotor and help evacuate gasses and dust, shed heat, and keep the brake pad surface clean. And in wet, raining conditions, the Vac-U-Slot helps push water off the braking surface for better stopping power. StopTech also uses a special metallurgy and directional cooling vanes to improve high temperature performance.
The slots also serve as a visual wear indicator. Slots are machined to the rotor's minimum thickness where it crosses the outside edge. If you cannot see the slots along the outside edge, the rotor has worn down to its discard depth. StopTech Sport rotor hats, edges, and internal vanes are finished in a durable black e-coat to prevent corrosion. The braking surfaces are left in a bare iron finish to improve the bed-in process of brake pads.
BMW Fitments: 3 Series
- Machined slots evacuate gasses, dust, and water
- Key features help improve high temperature performance
- Slots serve as easy visual wear indicators
- Hats, edges, and cooling vanes finished in corrosion-preventing black e-coat
E90 / E91 / E92 / E93 (06-13) > 335d
E90 / E91 / E92 / E93 (06-13) > 335i
E90 / E91 / E92 / E93 (06-13) > 335is
E90 / E91 / E92 / E93 (06-13) > 335xi