BMW Z4 Big Brake Kit Upgrade / TTSPORT Classic 7640
The BMW Z4 is a sporty two-seat roadster built for spirited driving, capable of 0-62 mph in around 6.7 seconds. But the factory floating calipers that come on the Z4 don't always keep up with that kind of performance — under hard or repeated braking, drivers often notice a soft, less confident pedal and reduced stopping power right when they need it most. This case walks through a straightforward fix: swapping the stock front brakes for a TTSPORT Classic 7640 six-piston big brake kit.
Floating calipers rely on a single piston (or a pair) sliding on pins to clamp the rotor from both sides. It's a simple, cost-effective design, but it flexes more under load and applies force less evenly than a fixed caliper — which is exactly what shows up as a mushy pedal on a car like the Z4 that's capable of hard, repeated stops.
The Upgrade: TTSPORT Classic 7640 Six-Piston Kit
A fixed six-piston caliper does away with the sliding pins and clamps the rotor directly from both sides. That means more even clamping force across the pad, a firmer and more linear pedal, and better resistance to flex when the brakes are worked hard. For this Z4, TTSPORT paired its 7640 caliper with a 380mm high-carbon rotor up front — a meaningful jump in swept area and heat capacity over the factory setup.
Vehicle & Kit Specs
| Item | Specification |
|---|---|
| Vehicle | BMW Z4, 19-inch wheels |
| Front caliper | TTSPORT Classic 7640 forged six-piston caliper |
| Front rotor | TTSPORT 380mm high-carbon rotor |
| Bracket | Vehicle-specific caliper bracket for BMW Z4 |
| Pads / lines | TTSPORT performance brake pads, stainless steel brake lines |
| Hardware | Brake fluid, mounting bolts and hardware |
Below are TTSPORT's full published specifications for the 7640 caliper used in this build:
| Brake Caliper | |
|---|---|
| Series | Classic Series |
| Model / Application | 7640 |
| Axle Position | Front |
| Piston Count | 6-piston |
| Piston Type | Two-piece heat-insulated pistons with dust boots |
| Piston Diameter | 27 mm × 2 / 33 mm × 2 / 38 mm × 2 |
| Caliper Dimensions | L 353 mm × W 162 mm × H 92 mm |
| Total Piston Area | 51.2 cm² per caliper, all pistons combined |
| Manufacturing Process | Two-piece forged aluminum body |
| Net Weight | 3.70 kg per caliper, without pads |
| Surface Finish | High-temperature gloss coating |
| Recommended Wheel Size | 18 in or larger |
| Recommended Rotor Size | Ø355–380 mm × 32 mm |
| Fitment & Installation | |
| Minimum Spoke Clearance (mm) | 98 |
| Caliper Mounting Type | Radial mount with vehicle-specific caliper brackets |
| Brake Line Fitting Type | Vehicle-specific fittings; caliper-side and chassis-side fittings vary by application |
Why It Works
- Forged two-piece aluminum caliper body resists flex under hard braking, giving a firmer, more predictable pedal than the stock floating caliper.
- The 380mm rotor adds swept area and thermal mass versus the factory disc, helping the brakes hold up better under repeated hard stops.
- The kit is engineered to clear the Z4's 19-inch factory wheels using a vehicle-specific bracket rather than a universal, one-size-fits-all mount.
- Two-piece heat-insulated pistons with dust boots handle sustained high temperatures and are compatible with carbon-ceramic rotors as well as standard discs.
Installation Gallery
What brake kit was installed on this BMW Z4?
What wheel size does the TTSPORT 7640 kit fit on the Z4?
Can the TTSPORT 7640 caliper be used with carbon-ceramic rotors?
What rotor sizes pair with the TTSPORT 7640 caliper?
Need fitment confirmation? Choose the closest TTSPORT series or send your vehicle, wheel size, and intended use before ordering.