BMW X3 Big Brake Kit Upgrade / TTSPORT Classic 8703
The third-generation BMW X3 comes with a lot of chassis potential thanks to its B48 turbo four and genuinely sporty suspension tuning — but the factory brakes are sized for daily driving, not for the kind of pace this platform can actually hold. This case study covers a straightforward fix: a TTSPORT front six-piston / rear four-piston big brake kit that adds stopping power and a firmer pedal without giving up the factory electronic parking brake.
The owner kept the factory 20-inch wheels and swapped in a TTSPORT TT8703 six-piston forged caliper up front paired with a 405x34mm high-carbon heat-treated rotor — a notable jump over the stock single-piston setup in both clamping force and heat capacity.
Vehicle & Kit Specs
| Item | Specification |
|---|---|
| Vehicle | BMW X3 (G01), 20-inch wheels |
| Front caliper | TTSPORT TT8703 six-piston forged caliper |
| Front rotor | 405x34mm high-carbon heat-treated curved-vane rotor |
| Rear caliper | TTSPORT TT6411 four-piston forged caliper with EPB electronic parking brake caliper |
| Rear rotor | 380x28mm high-carbon heat-treated curved-vane rotor |
| Lines | TTSPORT stainless steel brake lines |
Why It Works
Bigger rotors mean more surface area and more mass to absorb heat, so the front 405mm and rear 380mm discs resist fade better than the stock brakes over repeated hard stops. The six-piston front and four-piston rear calipers spread clamping force more evenly across the pad, which translates into a firmer, more linear pedal instead of the soft, long-travel feel of the factory single-piston units.
- Front six-piston + rear four-piston layout for balanced brake bias front to rear
- Larger 405mm/380mm rotors add heat capacity for more consistent stops under repeated braking
- Dedicated EPB rear caliper keeps the factory electronic parking brake fully functional
Installation Gallery
Frequently Asked Questions
What TTSPORT brake kit was installed on this BMW X3?
Does this big brake kit work with the factory electronic parking brake?
What wheel size does this X3 setup fit behind?
Need fitment confirmation? Choose the closest TTSPORT series or send your vehicle, wheel size, and intended use before ordering.