Cadillac CT4 Big Brake Kit Upgrade / TTSPORT Classic 8657
Cadillac's CT4 carries a lot of the brand's performance ambition on a compact sport-sedan frame, but the factory brake hardware isn't always up to matching it. This case study covers a CT4 fitted with a TTSPORT 8657 big brake kit — a forged six-piston front caliper paired with a 380x34mm high-carbon heat-treated rotor — installed behind the car's stock 19-inch wheels.
The goal here wasn't a track-only setup — it's an OEM+ upgrade meant to give the CT4 a firmer pedal and more consistent stopping power for daily and spirited driving, without giving up the factory wheel fitment.
Vehicle & Kit Specs
Here's the hardware breakdown for this install:
| Item | Specification |
|---|---|
| Vehicle | Cadillac CT4, 19-inch factory wheels |
| Front caliper | TTSPORT 8657 forged, split-design six-piston caliper, approx. 3.90kg per unit, ventilated pistons, compatible with 355-405mm rotors |
| Front rotor | 380x34mm high-carbon heat-treated curved-vane rotor |
| Lines | TTSPORT stainless steel brake lines |
Why It Works
The 8657's split forged construction is stiffer under hydraulic load than a stock sliding caliper, so more of the pedal input goes directly into clamping force instead of flexing the caliper body. That's the difference between a soft, sponge pedal and a firm one you can modulate precisely.
Going to a 380x34mm rotor also adds usable mass and surface area over the factory disc, which means more thermal capacity to absorb heat during repeated hard stops — the real driver of brake fade. The stainless lines swap out the factory rubber hose, which can expand slightly under pressure and rob some pedal firmness.
- Six-piston forged caliper for a stiffer, more direct pedal feel
- 380x34mm rotor adds heat capacity for more consistent stopping power
- Fits behind the CT4's stock 19-inch wheels
Installation Gallery
What rotor size does the TTSPORT 8657 kit use on this Cadillac CT4?
What kind of caliper is the TTSPORT 8657?
Does the kit include brake lines?
Need fitment confirmation? Choose the closest TTSPORT series or send your vehicle, wheel size, and intended use before ordering.