BMW 3 Series (320Li) Big Brake Kit Upgrade / TTSPORT Classic 8657
This 2018 BMW 320Li (3 Series) runs the common 2.0T setup — 184 hp, inline-four, 8-speed automatic — on unmodified factory 18-inch wheels. Nothing exotic about the platform, which makes it a good baseline for a straightforward brake upgrade: swap the stock calipers and rotors for a TTSPORT front-and-rear big brake kit and see what changes.
The build went front and rear: a TT8657 six-piston forged caliper with a 355x32mm Dacromet-coated drilled rotor up front, and a TT8901 four-piston forged caliper with a 345x28mm Dacromet-coated drilled rotor in back, each axle running its own TTSPORT stainless steel brake line. The whole kit fits inside the car's stock 18-inch wheel — no spacers, no wheel swap.
Vehicle & Kit Specs
| Item | Specification |
|---|---|
| Vehicle | 2018 BMW 320Li (3 Series), 2.0T L4, 184 hp, 8-speed automatic, factory 18-inch wheels, no spacers |
| Front caliper | TTSPORT TT8657 six-piston forged caliper |
| Front rotor | TT355x32mm Dacromet-coated drilled rotor |
| Rear caliper | TTSPORT TT8901 four-piston forged caliper |
| Rear rotor | TT345x28mm Dacromet-coated drilled rotor |
| Bracket | Custom vehicle-specific caliper bracket, finished red to match the calipers |
| Lines | TTSPORT stainless steel braided brake lines, front and rear |
TT8657 and TT8901 are two of the more popular calipers in the TTSPORT lineup for this kind of build — forged construction for higher rigidity at lower weight compared with a cast piece. The rotors get a Dacromet finish over the drilled surface, which protects the areas the pads don't sweep from rust, while the drilling pattern helps pull heat away from the friction surface.
Why It Works
- Weighed on a scale, the TTSPORT caliper-and-pad assembly comes in at nearly half the weight of the factory caliper it replaces.
- The upgraded rotors are both larger in diameter and lighter than the stock discs — more braking surface without adding rotating mass.
- Less unsprung weight at each corner means the suspension and brakes respond quicker to inputs.
- A bigger rotor and forged caliper raise the friction available at the pad-to-rotor interface, which sharpens pedal response and shortens the time between input and stopping force.
- All of this happens inside the stock 18-inch wheel, so there's no need for spacers or a wheel change to make it fit.
Installation Gallery
FAQ
What size wheels does this BMW 320Li big brake kit fit under?
What's included in the TTSPORT kit used on this BMW 3 Series?
Why use a Dacromet coating on the rotors?
Need fitment confirmation? Choose the closest TTSPORT series or send your vehicle, wheel size, and intended use before ordering.