Front left slotted brake rotor to fit 1991-1998 E31 840ci, 850i, and 850ci models.. This rotor fits cars with either Ate single-piston or Brembo 4-piston calipers.
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 CNC slotting 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.
- 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
StopTech is an enthusiast-driven manufacturer of replacement brake components, brake upgrades, and Big Brake Kits. Since their beginnings in 1999, StopTech has operated under a "better than OE" approach to design and manufacturing. Most obvious is their electrostatic anti-corrosion coating that signaled the end to cheap, aftermarket rusty rotors. Under the surface, every StopTech slotted rotor is CNC machined from a High Carbon blank disc. The High Carbon approach results in a brake disc with greater capacity for heat absorption. This results in less deformation of the braking surface, aka "warping", better resistance to surface cracks, and greater performance overall.
Sold per brake rotor.
BMW Fitments: 8 Series
E31 (91-97) > 840Ci
E31 (91-97) > 850Ci