BMW X4 Big Brake Kit Upgrade / TTSPORT Classic 8657
This BMW X4 pairs a turbocharged 2.0L four-cylinder with a genuinely quick 0-60 time, but the factory brakes weren't built to match the way the owner wanted to drive it. The fix here wasn't a pad-and-fluid refresh — it's a full front-and-rear TTSPORT big brake kit, finished in a custom Tiffany blue to match the owner's build.
The setup runs TTSPORT's front six-piston TT8657 caliper with a 380x34mm high-carbon heat-treated curved-vane rotor, plus a rear four-piston TT8901 caliper on a 380x28mm rotor of the same rotor design. Both calipers and the caliper brackets were finished to match, front to back.
Vehicle & Kit Specs
| Item | Specification |
|---|---|
| Vehicle | BMW X4, 19-inch wheels |
| Front caliper | TTSPORT TT8657 two-piece forged six-piston caliper, custom Tiffany blue finish |
| Front rotor | 380mm x 34mm high-carbon heat-treated curved-vane rotor |
| Rear caliper | TTSPORT TT8901 two-piece forged four-piston caliper with TT EPD electric parking brake motor, custom Tiffany blue finish |
| Rear rotor | 380mm x 28mm high-carbon heat-treated curved-vane rotor |
| Bracket | Custom-painted caliper brackets, color-matched to the calipers |
Why It Works
Both the TT8657 and TT8901 calipers use a two-piece forged design, from the caliper body down to the mounting bolts. Forging tightens the grain structure of the metal, which is why TTSPORT rates the resulting caliper stiffness at roughly 30% higher than a cast caliper of comparable size — less flex under load means less pedal travel lost to caliper deformation and more consistent bite each time the pedal is pressed.
- Six-piston front / four-piston rear layout spreads clamping force across more pad area for stronger, more even bite than the factory single-piston calipers.
- 380mm rotors on both axles add mass and surface area over stock, which means more heat capacity before the brakes start to fade on repeated hard stops.
- The rear TT8901 caliper integrates a TT EPD electric parking brake motor, so the factory electronic parking brake still functions with the upgraded hardware.
- The kit was fitted behind the car's 19-inch wheels in this build, with calipers and brackets finished to match the wheel and body color scheme.
Installation Gallery
What wheel size does this BMW X4 big brake kit fit behind?
Does the rear kit still work with the X4's electronic parking brake?
What's included on the front and rear axles?
Need fitment confirmation? Choose the closest TTSPORT series or send your vehicle, wheel size, and intended use before ordering.