BMW 4 Series Big Brake Kit Upgrade / TTSPORT Classic 8610

The BMW 4 Series splits the difference between a 3 Series and a 5 Series — higher seating position, a roomier cabin, and either a turbo four or a turbo six under the hood depending on trim. What it doesn't get from the factory is a caliper built for repeated hard stops. This case looks at a 4 Series that had its front brakes swapped for a TTSPORT 8610 forged six-piston big brake kit, paired with a 390x36mm high-carbon rotor and stainless steel lines — all tucked behind the car's stock 19-inch wheels.

The 4 Series in this build runs a 430i/430i xDrive four-cylinder or an M440i xDrive six-cylinder, both mated to an 8-speed automatic — BMW dropped the manual on this generation entirely. Whatever's under the hood, the factory brakes still have to shed the same kinetic energy, and a small single-piston or twin-piston sliding caliper up front is the limiting factor once you start driving the car hard.

Vehicle & Kit Specs

The TT8610 caliper body is forged, not cast — a thousand-ton press stamps the blank at high pressure and density, which gives the caliper more resistance to flex than a typical cast unit. Less caliper flex under load means less pedal travel is wasted deforming the hardware, so the pedal itself feels firmer and more predictable.

Why It Works

• Forged caliper construction resists flex better than a stock sliding caliper, translating pedal input into clamping force more directly.
• Racing-grade pistons in three graduated sizes give more even pad pressure across the pad face for a more linear, responsive bite.
• The 390x36mm rotor and caliper package was sized to clear the car's factory 19-inch wheels — the gap between disc and spokes ended up close enough that TTSPORT describes it as "a sheet of paper" narrow.

Installation Gallery