Build sheet: what's on this 991
| Component | STOPFLEX specification |
|---|---|
| Vehicle | Porsche 911 (991) |
| Front calipers | Akebono 10-piston fixed calipers |
| Front rotors | STOPFLEX C/SiC carbon ceramic, 410 x 36 mm |
| Rear calipers | Brembo 4-piston fixed calipers |
| Rear rotors | STOPFLEX C/SiC carbon ceramic, 400 x 28 mm |
| Pad material | STOPFLEX street and track ceramic compound |
| Axle scope | Front and rear carbon ceramic conversion |
| Wheel target | 20-inch (clearance check required) |
Read this before you order
This is a custom big brake conversion, not a rotor-only swap. The factory front calipers come off and wide 10-piston Akebono units go on, so clearing a 20-inch wheel takes more than the right diameter — spoke shape and inner-barrel clearance around that front caliper both have to be checked against your exact wheel first.
What the upgrade does for you
| STOPFLEX feature | Why it matters on a 911 991 | What you notice |
|---|---|---|
| C/SiC carbon ceramic rotors, 410mm front / 400mm rear | The 991 chassis is happy to carry speed, so the brakes take the heat. Carbon ceramic holds friction where iron starts to heat-soak — around 0.3μ even at 900°C in testing. | A pedal that stays firm and repeatable through a long mountain descent or back-to-back hard stops instead of going long and vague. |
| Roughly half the weight of same-size steel rotors | Every kilo here is unsprung and rotating mass right at the wheel, where it hurts handling most on a sports car. | Lighter, quicker turn-in and suspension that settles faster over broken pavement. |
| Akebono 10-piston front caliper on the 36mm rotor | More pistons spread clamp force across a bigger pad, and the thick rotor gives the thermal mass to soak up repeated high-energy stops. | Even pad bite edge-to-edge and a brake that doesn't flinch when you use it hard, lap after lap. |
| Low-dust STOPFLEX pads with corrosion-proof rotors | On a 911 the wheels are always on display, and these cars sit through plenty of weather between drives. | Wheels that stay clean far longer, and rotors that don't surface-rust after a rainy week parked. |
| Long-fiber CCB construction with crackle-texture ceramic coating | Long fibers build real structural strength into the disc rather than relying on chopped fiber, and the finish shows through open spokes. | A rotor built to last on the street plus a genuinely premium look behind the wheel. |
What gets better
- Firmer, more consistent pedal when the brakes get hot.
- Less unsprung mass for sharper turn-in and ride control.
- Normal cold bite even around -20°C on the first stop.
- Very low brake dust and rotors that don't rust after rain.
- Street-use life can reach about 250,000 to 300,000 km off-track.
What to confirm first
- Exact 991 variant and model year.
- 20-inch wheel barrel diameter and spoke clearance around the front caliper.
- Front and rear scope — this build converts both axles.
- Correct STOPFLEX pad for your mix of street and harder driving.
- Proper installation and a full bed-in before you push the car.
If you're not sure your car matches the spec shown here, send us your wheel and variant details and we'll confirm Porsche 911 (991) fitment before you order through our Porsche CCB collection.
Build gallery
911 991 CCB questions
Why go from the factory front caliper to a 10-piston Akebono on a 911 991?
Ten pistons spread clamp force more evenly across the larger 410mm STOPFLEX rotor and increase pad contact area. That means more even heat into the rotor face, fewer localized hot spots, and a firmer, more predictable pedal when you lean on the brakes repeatedly.
Does a carbon ceramic setup actually change how the 911 991 feels to drive?
It can. STOPFLEX carbon ceramic rotors weigh about half what the same-size steel rotors do, so you cut unsprung and rotating mass at each corner. On a 911 that tends to show up as quicker turn-in, calmer suspension over rough pavement, and steering that feels a touch more alert.
Is this setup okay for daily street driving, not just hard runs?
Yes. Paired with the right STOPFLEX pad, cold braking stays normal even around -20°C on the first stop, dust stays very low, and normal-temperature friction can exceed 0.4μ, so the car feels responsive in everyday driving while keeping the heat tolerance for harder use.
Will the 410mm front and 400mm rear rotors clear 20-inch wheels?
This build is planned around 20-inch wheels, but you still have to check clearance. Rotor diameter is only part of it; the wide 10-piston front caliper means barrel diameter and spoke shape both need to be verified against your exact wheel before ordering.
How long do STOPFLEX carbon ceramic rotors last on a street-driven 911?
On the street they last far longer than iron. STOPFLEX street-use lifespan can reach about 250,000 to 300,000 km when the car isn't tracked, though your real mileage depends on driving style, pad choice, and conditions. The rotors also don't rust after rain.
