BMW BRAKE DISC

Grey Cast-Iron G3000 – cast, precision-machined and dynamically balanced to BMW Group OE standards for perfect fit, sport-level heat capacity and “Ultimate Driving Machine” pedal feel.

Manufactured in an IATF-16949 facility that also feeds BMW, MINI and Rolls-Royce assembly lines.

1. 100 % BMW OE GEOMETRY

– CNC-turned outer Ø, thickness, bolt circle and hat height to BMW blueprint—installs without spacers, shims or coding.

– Wheel-hub register and ABS tone-ring teeth held ± 0.01 mm—zero run-out, no brake judder or DSC/ABS faults.

2. GREY CAST-IRON G3000 COMPOSITION

– 3.3 % C, 2.0 % Si, 0.7 % Mn, ≤ 0.15 % P, ≤ 0.12 % S—identical chemistry used on 3 Series, 5 Series, X3, X5 production.

– Pearlite matrix, 200-230 HB: high wear resistance, excellent thermal conductivity and natural damping for BMW-class NVH.

3. HIGH-PERFORMANCE VENTILATED CORE

– 60 directional “pillar” or curved vanes increase airflow 20 %, cutting peak temperature 80 °C during repeated 250-80 km/h Autobahn stops.

– Single-piece casting—no welded seams to fail under M-Power track-day thermal cycles.

4. SURFACE FINISH & PRECISION BALANCE

– Non-directional swirl, Ra ≤ 1.6 µm—beds-in within 20 stops, no greenfade.

– Dynamic balanced ≤ 0.8 g—steering-wheel shake free at BMW’s 250 km/h (155 mph) limit.

5. ANTI-CORROSION COATING

– Full-surface Geomet® or electro-zinc layer—144 h salt-spray per ASTM B117, survives Alpine winters and coastal humidity.

– Friction faces uncoated for immediate use; protective oil film burns off on first brake application.

6. QUIET, LOW-DUST DESIGN

– Precision dual-radius chamfers plus 0.30 mm under-cut slots prevent pad-knock and squeal.

– Optimised for BMW low-met and ceramic formulations—low dust, no black rims on M light-alloy wheels.

7. VALIDATION TESTS

– 500-cycle AK-Master (250-80 km/h, 5 kW power) wear ≤ 0.30 mm—within BMW 0.5 mm limit.

– Thermal shock: 600 °C → 20 °C water quench, 50 cycles—no surface cracks, distortion < 0.03 mm.

8. SERVICE LIFE & FITMENT

– 80 000–100 000 km normal street use; 40 000 km severe duty (taxi, police, Alpine passes).

– Direct replacement for selected BMW models—see reverse for PR-code / VIN list.

– Replace in axle pairs and use BMW-specified pads for optimum pedal feel and DSC compatibility.

INSTALLATION NOTE

Clean hub face with wire brush, apply thin anti-seize on contact shoulders only, torque wheel bolts to 140 N·m (M14) in star pattern.

Bed-in: 8 moderate stops 100 km/h → 30 km/h with 30 s cooling between each.

TYPICAL FRONT DISC SPEC (18″ wheel, 3 Series G20)

Outer Ø: 348 mm

Thickness new: 36 mm

Min. thickness: 34 mm

Centre bore: 75.0 mm

Bolt pattern: 5×120 mm

Weight: 9.2 kg

Material: G3000 grey cast iron, heat-treated

Max run-out: 0.025 mm

Thickness variation: ≤ 0.010 mm

Restore the precise, confident braking BMW engineers designed—choose BMW Genuine Technology brake discs.