BMW 5 Series (G68) Big Brake Kit Upgrade / TTSPORT Classic 8657S
The BMW 5 Series (G68) doesn't lack for power or polish, but its factory brakes are still tuned for daily commuting, not for a driver who wants to lean on the car. A soft, long-travel pedal is fine in traffic and starts to feel vague the moment you push the car harder. This build swaps the stock setup for a TTSPORT front six-piston / rear four-piston-plus-EPB big brake kit built specifically for this platform.
The car is a BMW 5 Series (G68) on 20-inch wheels. Up front, the owner installed the TTSPORT 8657S six-piston forged caliper paired with a 405mm rotor. Out back, the TTSPORT EP4 electromechanical caliper handles both service braking and the electronic parking brake, matched to a 380mm rotor. The kit came with custom vehicle-specific caliper brackets, TTSPORT performance pads, stainless steel lines, fluid, and mounting hardware — everything needed for a complete, no-guesswork install.
Vehicle & Kit Specs
Here's the full hardware breakdown for this G68 install:
| Item | Specification |
|---|---|
| Vehicle | BMW 5 Series (G68), 20-inch wheels |
| Front caliper | TTSPORT 8657S forged six-piston caliper |
| Front rotor | TTSPORT 405mm rotor |
| Rear caliper | TTSPORT EP4 electromechanical caliper (four-piston service brake + single-piston electronic parking brake) |
| Rear rotor | TTSPORT 380mm rotor |
| Bracket | Custom vehicle-specific caliper brackets |
| Pads / lines | TTSPORT high-performance pads, stainless steel brake lines |
| Hardware | Brake fluid, mounting bolts, fasteners |
The front caliper in this kit is the TTSPORT 8657S from the Classic Series; its full spec sheet is below.
| Brake Caliper | |
|---|---|
| Series | Classic Series |
| Model / Application | 8657S |
| Axle Position | Front |
| Piston Count | 6-piston |
| Piston Type | Two-piece heat-insulated pistons with dust boots |
| Piston Diameter | 30 mm × 2 / 34 mm × 2 / 38 mm × 2 |
| Caliper Dimensions | L 350 mm × W 165 mm × H 92.64 mm |
| Total Piston Area | 55.0 cm² per caliper, all pistons combined |
| Manufacturing Process | Two-piece forged aluminum body |
| Net Weight | 4.05 kg per caliper, without pads |
| Surface Finish | High-temperature gloss coating |
| Recommended Wheel Size | 18 in or larger |
| Recommended Rotor Size | Ø355–405 mm × 32–34 mm |
| Fitment & Installation | |
| Minimum Spoke Clearance (mm) | 107 |
| 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
The 8657S is a two-piece forged caliper with a machined-out, weight-relieved body — forged construction resists the flex that a stock cast caliper shows under hard braking, so pedal input translates more directly into clamping force instead of getting absorbed by caliper deformation. Its six pistons are staged in a progressive layout (30mm / 34mm / 38mm pairs) for a linear, controllable pedal feel rather than an on/off bite. The two-piece heat-insulated pistons and high-temp seals keep clamping force consistent as things heat up.
- Rear TTSPORT EP4 caliper keeps a symmetrical, vented body with the same two-piece heat-insulated pistons, so front and rear brake bias stays balanced instead of the rear lagging behind an upgraded front axle.
- The EP4's single-piston electric motor handles parking brake duty independently of the four service-brake pistons, so upgrading rear clamping force doesn't touch the factory electronic parking brake logic.
- Custom vehicle-specific brackets place the larger 405mm/380mm rotors on the correct offset for the G68's 20-inch wheels, with no spacers needed.
Installation Gallery
Frequently Asked Questions
Does this TTSPORT kit clear the stock 20-inch wheels on the G68?
Does the rear TTSPORT EP4 caliper keep the electronic parking brake working?
What's included in the TTSPORT kit for this G68 install?
Need fitment confirmation? Choose the closest TTSPORT series or send your vehicle, wheel size, and intended use before ordering.