The build: parts and fitment
| Item | Specification |
|---|---|
| Vehicle | Audi S4 Avant (B9) |
| Front calipers | AP Racing CP9561 6-piston Radi-CAL |
| Front rotors | STOPFLEX 380 mm carbon ceramic |
| Front pads | STOPFLEX street-focused ceramic compound |
| Rear brakes | Factory rear brake retained |
| Front axle weight saved | About 14 kg vs the original front setup |
| Wheel context | Configured around 19-inch wheels |
| Scope | Custom front big brake kit |
Confirm before you order
This is a custom front big brake kit, not a stock caliper swap. It runs AP Racing CP9561 calipers, 380 mm STOPFLEX carbon ceramic rotors, and application-specific mounting hardware. It's built around 19-inch wheels, but caliper shape, spoke design, and wheel offset all vary, so confirm wheel clearance before buying.
What the front CCB upgrade changes
| STOPFLEX front package | Why it matters on the S4 Avant B9 | What you notice |
|---|---|---|
| 380 mm carbon ceramic rotors | The Avant carries weight ahead of the front axle, so the nose feels heavy when you push it through a series of corners. | About 14 kg off the front axle, cleaner steering, and a front end more willing to turn in. |
| Long-fiber CCB construction | Front brakes take the highest thermal load on this car during repeated hard stops down a grade or a fast back road. | Friction holds where iron rotors start to fade, so the pedal stays consistent stop after stop. |
| AP Racing CP9561 6-piston Radi-CAL caliper | A stiff caliper body resists flex under high clamp loads, which a comfort-tuned factory caliper isn't built to do. | A firmer, more precise pedal with less travel before the brakes bite. |
| STOPFLEX street ceramic pads | A daily S4 lives with wet weather, car washes, and traffic, where iron rotors rust and dusty pads coat the wheels. | Very low brake dust and rotors that don't rust orange after rain, so the wheels stay clean. |
What gets better
- About 14 kg less rotating unsprung mass at the front axle.
- Cleaner turn-in and a front end that feels less reluctant to change direction.
- Heat tolerance that keeps the pedal consistent through repeated hard stops.
- Firmer, more precise pedal feel from the stiff Radi-CAL caliper.
- Very low brake dust and rotors that won't rust after rain.
What to confirm first
- Wheel clearance against your exact 19-inch wheel design.
- That you want a front-axle upgrade with the factory rear brake retained.
- That the pad choice matches how you actually drive the car.
- Caliper, rotor, and bracket hardware all matched to the B9 application.
If you're not sure your car matches the spec shown here, send us your details and we'll confirm Audi S4 Avant (B9) fitment before you order through our Audi CCB collection.
Build gallery
Common questions
Why upgrade only the front brakes on the Audi S4 Avant B9?
The front axle does most of the braking work and takes most of the heat, especially on a nose-heavy wagon like the S4 Avant. A front-only carbon ceramic conversion gives you the biggest gain in pedal consistency, heat tolerance, and turn-in feel while leaving the factory rear brake and electronic parking brake untouched.
Is the AP Racing CP9561 caliper okay for daily driving?
Yes. The CP9561 is a road-usable Radi-CAL caliper, and paired with STOPFLEX street ceramic pads it stays controlled and predictable in normal traffic. It is far easier to live with day to day than most people expect from a six-piston big brake kit.
Does this upgrade actually help the S4's nose-heavy feel?
It helps where it counts. This build cuts about 14 kg from the front axle versus the stock setup. Trimming rotating unsprung mass at the nose makes the steering feel cleaner and the front end more willing to change direction, though it will not rewrite the car's basic weight distribution.
Will the 380 mm front kit clear factory 19-inch wheels?
The kit is configured around 19-inch wheel fitment, but you should always confirm clearance before buying. Caliper shape, spoke design, barrel profile, and wheel offset all matter, so a template check is the safest way to be sure.
Is this a direct bolt-on replacement for the stock front brakes?
No. This is a custom front big brake kit using AP Racing CP9561 calipers, 380 mm STOPFLEX carbon ceramic rotors, and the correct mounting hardware. It is not a simple stock caliper swap, so the parts have to be matched to the application.
How long do STOPFLEX carbon ceramic rotors last on a street car?
On a street-driven car that never sees track use, STOPFLEX carbon ceramic rotors can last roughly 250,000 to 300,000 km when the system is paired and maintained properly. They also resist rust, so they will not develop the orange surface film iron discs get after rain.
