MG/ROVER BRAKE DISC

Grey Cast-Iron G3000 – cast, machined and balanced to original MG Rover OE drawings for correct fit, classic feel and modern safety.

Manufactured in an IATF-16949 foundry and supplied to MG Rover specialists across the UK and EU.

1. AUTHENTIC OE GEOMETRY

– CNC-turned outer Ø, thickness and 4-stud / 5-stud PCD to Rover Group blueprint—fits without spacers or shims.

– Hub register and ABS ring location (where fitted) held ± 0.02 mm—eliminates run-out, pedal pulsation and ABS errors.

2. GREY CAST-IRON G3000 SPECIFICATION

– 3.3 % C, 2.0 % Si, 0.7 % Mn, ≤ 0.15 % P, ≤ 0.12 % S—the same pearlite/ferrite matrix used on MG ZR, ZS, ZT and Rover 25/45/75.

– 200-230 HB hardness for long wear, high thermal conductivity and natural damping of NVH on older, less-insulated bodyshells.

3. HIGH-FLOW VENTILATED CORE

– 36 curved vanes (or 12 straight vanes on classic 256 mm discs) increase airflow 12 %, cutting peak temp 50 °C on fast A-road descents.

– One-piece casting—no welded centres to fail when pushing an MG-F or TF through mountain passes.

4. SWIRL FINISH & PRECISION BALANCE

– Non-directional swirl, Ra ≤ 1.8 µm—beds-in within 15 stops, no greenfade.

– Dynamic balanced ≤ 1 g—mirror-shake free at MG’s 185 km/h (115 mph) top-speed test (MG ZT 190).

5. ANTI-CORROSION FINISH

– Electro-zinc coating on hat, outer rim and vane mouths—96 h salt-spray, keeping rust at bay on daily-driven British winter roads.

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

6. QUIET, LOW-DUST PROFILE

– Edge chamfers and 0.35 mm under-cut slots prevent pad-knock and squeal on older sliding-pin callipers.

– Compatible with ECE-R90 low-met or ceramic pads—low dust, no black residue on classic alloy wheels.

7. VALIDATION TESTS

– 200-cycle AK-Master (100-30 km/h, 3 kW power) wear ≤ 0.40 mm—within Rover 0.5 mm wear limit.

– Thermal shock: 450 °C → 20 °C water quench, 30 cycles—no surface cracks, distortion < 0.05 mm.

8. SERVICE LIFE & FITMENT

– 60 000–80 000 km normal UK/EU street use; 30 000 km severe duty (city courier, Cornish moorland routes).

– Direct replacement for selected MG Rover cars—see reverse for VIN/RON and chassis number chart.

– Replace in axle pairs and use Rover-specified pads for correct bite and pedal travel.

INSTALLATION TIP

Clean hub flange with wire brush, smear thin copper grease on contact shoulders only, torque wheel nuts to 85 N·m (M12) in diagonal sequence.

Bed-in: 8 moderate stops 70 km/h → 30 km/h with 20 s cooling between each.

TYPICAL FRONT DISC SPEC (15″ wheel, MG ZR / Rover 25)

Outer Ø: 262 mm

Thickness new: 22 mm

Min. thickness: 20 mm

Centre bore: 56.1 mm

Stud pattern: 4×100 mm

Weight: 5.1 kg

Material: G3000 grey cast iron, heat-treated

Max run-out: 0.03 mm

Thickness variation: ≤ 0.012 mm

Keep the heritage alive—fit MG/Rover Genuine Technology brake discs and enjoy confident, classic British braking every mile.