S66A-S66B-S66C
Front 6-piston caliper for mid-size and large cars (B/C class)
Specifications
S66A / S66B / S66C — split 6-piston TAVRUS calipers for the front axle of B- and C-class cars.
OVERVIEW
S66A, S66B and S66C are mass-produced 6-piston calipers developed in-house. The body is forged from aluminium alloy: forging delivers high rigidity, tensile strength, toughness and material density. Compared with cast aluminium calipers, body rigidity is about 50% higher, which reduces the risk of caliper failure in service. The built-in double oil seal (instead of ordinary external dust boots) makes the brake feel and reaction more precise. After anodizing and vacuum coating (CVD) the colour is locked in: the coating does not crack or peel and gives the caliper a metallic sheen and vivid colour.
Installation improves the look of the wheel and lets the car handle varied road conditions with confidence — from daily driving to the track.
HIGHLIGHTS
• A series of three 6-piston calipers: S66A — the base body; S66B — a narrow body for those who do not want to fit spacers; S66C — an ultra-narrow body that fits most stock wheels without spacers.
• More pistons — a linear, predictable pedal.
• After multi-stage testing, performance is about 35% above the stock caliper.
• With high-performance pads it confidently handles intense driving — from mountain roads to the track.
CALIPER SPECIFICATIONS
• Weight: S66A — 3310 g, S66B — 3008 g, S66C — 2900 g (per piece)
• Piston area: 50.41 cm²
• Piston diameter: 38 mm × 2 / 32 mm × 2 / 28 mm × 2
• Brake disc diameter: Ø355 mm – Ø332 mm
• Brake disc thickness: max 34 mm / min 30 mm
• Caliper dimensions: S66A — D160.2 × H76.048 × W285 mm; S66B — D144.4 × H76.048 × W285 mm; S66C — D138.4 × H76.048 × W285 mm
• Oil inlet thread: M10×1
• Mounting hole centre distance: 180 mm
• Mounting hole offset: S66A — 40 mm; S66B — 34.1 mm; S66C — 31.1 mm
• Mounting hole diameter: 12.25 mm
• Distance from mounting plane to the top of the disc: S66A — 45.71 mm; S66B — 45.76 mm; S66C — 45.76 mm
BRAKE DISC
• Friction surface width: 54.5 mm
• Ventilation: Ø355 mm × 32 — 72 curved ducts, 7 slots, PCD 233 mm; Ø332 mm × 32 — 72 curved ducts, 6 slots, PCD 210 mm
• Heat treatment: 580 °C heating / 120 °C cooling, cycled for 72 h
• Mounting hole diameter: Ø8.1 mm
• Centring ring: Ø355 × 32 — Ø209 mm (petal step 2.5 mm); Ø332 × 32 — Ø190 mm (petal step 2.5 mm)
• Surface treatment: iron phosphating, ground friction surface
• Disc standard: GG20HC
BRAKE PADS
• Model: S66A / S66B
• Thickness: 18 mm (S66A) / 14 mm (S66B)
• Friction surface width: 50 mm
• Friction block area: 67.31 cm² × 2 pads per caliper
• Compound: F500 (standard) / F600 (street, optional) / S750 (street & track, optional) / R900 (track, optional) / S800 (for carbon-ceramic discs, optional)
QUALITY CONTROL
• Forged body tensile strength: Qb ≥ 320 MPa
• Body hardness: HV ≥ 400
• Low-pressure seal test: 0.4 MPa air, hold 5 s, pressure drop ≤ 100 Pa
• High-pressure seal test: 12 MPa air, hold 5 s, pressure drop ≤ 0.2 MPa
• Appearance: anodized surface free of damage, uniform colour and gloss
• Ultra-high pressure test: sampled calipers withstand 30 MPa oil pressure without failure
• Other characteristics per QC/T592.
Photos
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730529015803848.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730529144779680.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730529171165869.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730529188400889.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730529253798405.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730536951648948.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730536962784415.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730536970633807.png)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730536996918157.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730537006954507.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730537015477642.png)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730537028851701.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730537038641859.webp)
 S66A_S66B_S66C large six piston caliper (B-cla/images/1730537045507525.png)