The Xiaomi SU7 Max is a disruptor. With 673 horsepower and a 0-100 km/h time of 2.78 seconds, it embarrasses supercars costing five times as much. But there is one glaring issue: The Brakes. The factory fitted Brembo 4-piston front calipers are simply undersized for a 2.2-ton missile. The pad surface area is small, and the thermal capacity is limited. We fixed this by installing the ultimate braking solution: Akebono 10-Piston Calipers paired with StopFlex 420mm Carbon Ceramic Rotors.
The Elephant in the Room: 4-Piston Brakes on a 673HP Car
Let's look at the physics. You have:
- Mass: ~2,200 kg (4,850 lbs)
- Power: 673 HP
- Stock Brakes: Small 4-Piston Brembo with Iron Rotors
This is a recipe for heat soak. In track tests or canyon runs, the stock brakes fade quickly because they cannot dissipate the kinetic energy fast enough. The pedal gets long, and confidence evaporates.
The "Ultra" Spec Build
We took inspiration from the SU7 Ultra prototype and built a system that matches the car's power output.
| Vehicle | Xiaomi SU7 Max |
|---|---|
| Front Hardware | Akebono 10-Piston + 420mm StopFlex CCB |
| Rear Hardware | Akebono 4-Piston + 410mm StopFlex CCB |
| Parking Brake | Retained Factory EPB Functionality |
| Wheel Size | 21-inch (Required for 420mm rotors) |
⚠️ Fitment Note
This build uses a massive 420mm front rotor. You must run 21-inch wheels to clear the 10-piston caliper. Do not attempt to fit this under the standard 19-inch or 20-inch wheels.
Why Carbon Ceramic is Mandatory
On a heavy, high-horsepower EV, carbon ceramic isn't a luxury; it's a solution.
1. Consistent Stopping Power
The StopFlex CCB rotors can handle temperatures exceeding 1,000°C. This means no matter how hard you drive, the brake pedal feels the same. No fade, no drama.
2. Unsprung Weight Reduction
The SU7 has a fantastic chassis. By removing ~20kg of rotating mass from the wheels, the suspension responds faster, making the car feel lighter and more agile in corners.
3. Pad Surface Area
The Akebono 10-piston caliper uses a brake pad that is nearly double the size of the stock pad. This spreads the heat load over a larger area, significantly extending pad life and improving modulation.
Installation Gallery
Xiaomi SU7 FAQ
Q: Does this affect the warranty?
Modifying the braking system will likely void the warranty on the stock brake components (which you are replacing anyway). However, it should not affect the warranty on the battery or motors. Always check with your local service center.
Q: Why 10 pistons? Isn't that overkill?
For a 200hp car? Yes. For a 673hp, 2.2-ton car? No. The 10-piston design allows for massive clamping force while maintaining a progressive, linear pedal feel that is easy to control in traffic.
Q: Does the rear electronic parking brake still work?
Yes. Our rear kit uses a specific bracket to mount the Akebono 4-piston caliper while retaining the factory EPB motor functionality. It works seamlessly with the car's software.
