BMW 3 Series GT Big Brake Kit Upgrade / TTSPORT Classic 8703
The BMW 3 Series GT pairs a raised, heavier hatchback body with the same braking hardware as the standard 3 Series sedan — fine for daily driving, less convincing once you start pushing the car. This case study covers a straightforward fix: a front-six/rear-four TTSPORT big brake kit that swaps in larger rotors and stiffer calipers front and rear.
The BMW 3 Series GT (320i/335i) uses a 2.0T or inline-six engine paired with an 8-speed automatic, in sDrive or xDrive configurations. It's a heavier car than the standard 3 Series sedan, which makes braking hardware more of a factor once you're driving it hard. This build went with TTSPORT's front-six/rear-four setup — a common, well-proven configuration for this platform.
Vehicle & Kit Specs
Here's the full hardware breakdown for this BMW 3 Series GT install, running 19-inch wheels.
| Item | Specification |
|---|---|
| Vehicle | BMW 3 Series GT, 19-inch wheels |
| Front caliper | TTSPORT TT8703 six-piston monobloc aluminum caliper, with factory dust boots and anti-rattle spring clips |
| Front rotor | TT 380x34mm high-carbon heat-treated slotted (fishhook) rotor |
| Rear caliper | TTSPORT TT8903 four-piston caliper |
| Rear rotor | TT 380x28mm high-carbon heat-treated slotted (fishhook) rotor |
| Lines / Hardware | TTSPORT stainless steel brake lines, mounting hardware |
Why It Works
A monobloc caliper is machined from a single piece of aluminum instead of bolted together in two halves, so there's less flex under clamping load — that translates directly into a firmer, more predictable pedal instead of the soft, sponge-like feel a stock caliper can develop when it's pushed hard.
- Six-piston front / four-piston rear calipers clamp against a larger pad area, spreading force more evenly across the rotor face.
- Bigger 380mm rotors front and rear carry more thermal mass, which helps resist fade during repeated hard stops.
- The fishhook slot pattern is oriented to clear brake dust and pad debris in the direction of rotor rotation, keeping the pad-rotor interface cleaner under load.
- Stainless steel lines on the rear axle resist the expansion that rubber lines can develop under pressure, keeping pedal feel more consistent.
Beyond the aluminum monobloc casting, the TT8703 front caliper is built with street-use details in mind — dust boots to protect the pistons and anti-rattle spring clips to keep the pads quiet at low speed. It's a caliper meant for daily driving as much as spirited use.
The customer also chose a custom yellow finish for this build. TTSPORT calipers ship in red, yellow, and black, and a paid custom-paint service is available if none of the standard colors fit the look you're after.
Installation Gallery
What does the TTSPORT front-six/rear-four kit include on this BMW 3 Series GT?
What wheel size was this BMW 3 Series GT running?
Can the calipers be finished in a custom color like the yellow shown here?
Need fitment confirmation? Choose the closest TTSPORT series or send your vehicle, wheel size, and intended use before ordering.