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The build & parts list
| Vehicle | Audi S4 (B9) sedan |
|---|---|
| Front rotor (STOPFLEX) | 380 x 34 mm long-fiber carbon ceramic disc |
| Front caliper context | Factory 6-piston Akebono, or certain 380mm aftermarket big brake kits |
| Pads | STOPFLEX low-dust ceramic compound |
| Target wheel | 19-inch (clearance verified per wheel design) |
| Axle scope | Front rotor upgrade |
Confirm before you order
This 380mm setup is presented for the S4 B9 factory Akebono 6-piston front brakes and for certain 380mm aftermarket big brake kits. If your car runs an aftermarket caliper, confirm rotor offset and hat dimensions first — and verify clearance against your specific 19-inch wheel before installation.
Why it works on the S4
| STOPFLEX feature | Why it matters on the S4 B9 | What you notice |
|---|---|---|
| Carbon ceramic disc, about half the weight of a same-size steel rotor | The S4 carries a lot of mass over the front axle, and the rotor sits right at the wheel where weight hurts most. | A lighter-feeling nose, cleaner turn-in, and suspension that reacts more freely over rough pavement. |
| High heat tolerance — surface friction holds near 0.3μ even around 900°C | Back-road pace and long descents pile heat into a front-biased AWD sedan faster than most owners expect. | The pedal stays consistent when a steel setup would start feeling heat-soaked. |
| Low-dust ceramic pad pairing | Factory S4 brakes coat 19-inch wheels in dark dust film between washes. | Wheels that stay clean far longer, with a brake package that looks the part on a premium sedan. |
| Rotors that don't rust | Daily-driven cars sit through rain, and steel rotors throw an orange film fast. | No surface rust after wet weather, even when the car sits a few days. |
| Long-fiber CCB construction | Street S4s rack up miles for years, so rotor longevity changes the real cost of the upgrade. | Street-use lifespan in the 250,000–300,000 km range when the car isn't tracked. |
What gets better
- Less unsprung and rotational mass at the front wheels
- Steadier pedal feel through repeated hard stops
- Much lower brake dust on the wheels
- No rotor rust after rain
- Long street life that spreads the cost over years
What to confirm first
- Whether your car runs the factory Akebono 6-piston or an aftermarket 380mm kit
- Rotor offset and hat dimensions if the caliper is aftermarket
- Clearance against your exact 19-inch wheel design
- That a front rotor swap matches how you actually use the car
If you're not sure whether your car has the factory Akebono setup or an aftermarket caliper, send us your details and we'll confirm Audi S4 B9 fitment before you order through our Audi CCB collection.
Build Gallery
Audi S4 B9 carbon ceramic brake FAQ
Does this rotor fit the factory Akebono calipers or only aftermarket kits?
The 380mm STOPFLEX front rotor is built as a direct replacement for the Audi S4 B9 factory 6-piston Akebono front brakes. It can also suit certain 380mm aftermarket big brake kits, but on aftermarket calipers you should confirm rotor offset and hat dimensions before ordering.
I already run an aftermarket big brake kit with steel rotors. Is swapping just the rotors worth it?
For a lot of owners, yes. If the caliper already does what you need, moving from steel to carbon ceramic rotors trims front-end weight, resists heat soak better, and cuts brake dust without you paying for a full new brake system.
Will I actually feel a difference from behind the wheel?
You can. The S4 carries a lot of weight over the nose, so cutting rotor mass reduces unsprung weight right at the front wheels. That tends to clean up turn-in, let the suspension work more freely, and keep braking feel more consistent when you lean on it.
Will the 380mm setup clear factory 19-inch wheels?
The upgrade is designed around 19-inch wheel fitment, but spoke shape and clearance vary by wheel. Confirm clearance on your exact wheel before you buy or install.
How long do these rotors last on a street-driven S4?
On normal road use they outlast typical steel rotors by a wide margin. Street-use lifespan can reach roughly 250,000 to 300,000 km when the car is not run on track.
