BMW F8x M3/M4 Big Brake Kit: How to Install (2015-2020)

A big brake kit for the BMW F8x M3/M4 replaces the factory 4-piston front calipers and one-piece rotors with a 6-piston monobloc setup and 380mm x 36mm two-piece floating discs, giving your 2015-2020 F80 M3 or F82 M4 the thermal capacity and pedal consistency to survive repeated hard laps. The 425-503 hp S55 twin-turbo carries roughly 3,540 lbs to triple-digit speeds all day, and the stock steel brakes — excellent on the street — start to fade after three or four aggressive laps at a track day. This guide walks through exactly what a big brake kit does, which parts you need, and how to install one in your own garage.

Why the F8x M3/M4 Needs a Big Brake Kit

The 2015-2020 BMW F80 M3 and F82 M4 leave the factory with 380mm x 30mm front rotors clamped by four-piston fixed calipers and 370mm x 24mm rear rotors — a strong street setup, but one that runs out of thermal headroom on track. The S55 3.0L twin-turbo inline-six makes 425 hp in the base car, 444 hp in the Competition, and 493-503 hp in the M4 GTS and CS, and it accelerates a roughly 3,540 lb coupe hard enough that a 130-to-40 mph braking zone dumps enormous heat into the discs. After a few laps the OE one-piece cast rotors soak up more heat than they can shed, the pad compound gasses out, and the pedal goes long.

A big brake kit (BBK) attacks the problem three ways: more pistons spread clamping force evenly across a larger pad, a thicker two-piece floating rotor adds thermal mass and lets the iron ring expand independently of its aluminum hat (which reduces cracking and coning), and the aluminum hat trims rotating and unsprung weight versus a heavy one-piece casting. The result is a firmer, more repeatable pedal lap after lap. In our Tampa shop we see F8x owners chase brake fade with fluid and pads first — smart, cheap steps — but once you are running slicks or 200-treadwear tires and consistent lap times, the calipers and rotors are the real bottleneck.

What You Need Before You Start

A big brake kit install on the F8x M3/M4 takes a competent DIYer about 3-4 hours per axle and requires the brake kit itself plus a few consumables. Here is the complete parts and tool checklist:

• The brake kit — calipers, two-piece rotors, mounting brackets, and hardware (the Alcon kit below includes everything for the axle).
• Race or track pads — matched to your caliper. The Alcon and Brembo 16mm calipers use a common motorsport pad footprint.
• High-temperature DOT 4 brake fluid — a racing fluid with a dry boiling point of 600°F (316°C) or higher; plan on two 500ml bottles for a full flush.
• Stainless braided brake lines (optional but recommended) — they eliminate the pedal softness of expanding rubber lines under heat.
• Tools — 17mm socket for the lug bolts, a torque wrench, a full metric socket and Allen/Torx set, a brake bleeder (pressure or vacuum), a flare-nut wrench for the banjo/line fittings, thread locker, and brake cleaner.

Race Pads That Match the Caliper

Hawk DTC-80 pads are the highest-torque compound Hawk builds for endurance racing, with a friction coefficient that holds steady from roughly 400°F to 1,600°F. They are the correct pad for the Alcon and Brembo 16mm race calipers and are strictly a track compound — expect noise and poor cold bite on the street. Budget one set per axle and inspect them after every event.

A Street-Friendly Pad and Rotor Refresh

If your F8x still lives mostly on the street, you may not need full race calipers yet. DFC 5000 Advanced low-metallic pads ship with the hardware kit and give quiet, low-dust daily performance, while a two-piece slotted rotor restores heat capacity without the price of a full BBK. This is the path we recommend for a car that sees the occasional canyon run or one track day a season.

How to Install a Big Brake Kit on Your F80 M3 / F82 M4

Installing a big brake kit on the F8x M3/M4 is a bolt-on job on the factory hubs — no cutting or fabrication — but brakes are safety-critical, so follow the torque and bleed steps exactly and always confirm figures against the instructions supplied with your kit. Work one axle at a time so you always have a reference side.

Step 1: Lift, Secure, and Remove the Wheels

Loosen the 17mm lug bolts, raise the car on a lift or jack stands rated for its weight, and remove the wheels. Never work under a car supported only by a jack. With the wheel off you have full access to the caliper and rotor.

Step 2: Remove the OE Calipers and Rotors

Unbolt the two caliper carrier bolts behind the hub (the factory front carrier bolts torque to about 81 lb-ft / 110 Nm, so they will be tight). Support the caliper — do not let it hang from the brake line — then crack the banjo or line fitting and let the fluid drain into a catch container. Pull the retaining screw and slide the one-piece rotor off the hat.

Step 3: Fit the New Brackets, Rotors, and Calipers

Clean the hub face so the new two-piece rotor sits flat, then bolt on the supplied radial mounting bracket with thread locker to the manufacturer-specified torque. Slide the 380mm front (or 355mm rear) two-piece rotor into place, then bolt the monobloc caliper to the bracket. Spin the rotor and confirm even pad-to-rotor clearance on both sides before moving on.

Step 4: Install Lines, Pads, and Bleed the System

Connect the braided or OE brake line with a fresh crush washer on each side of the banjo bolt, drop in your race pads, and fasten the pad retaining pins. Fill the reservoir with fresh high-temp DOT 4 fluid and bleed each corner — furthest from the master cylinder first — until clean, bubble-free fluid flows. Pump the pedal until it is firm and high before the car ever moves.

Step 5: Torque the Wheels and Bed the Pads

Torque the lug bolts to 88 lb-ft (120 Nm) in a star pattern. Then bed the pads: from about 35 mph, make 8-10 moderate stops down to 5-10 mph without coming to a complete halt, then a few harder stops, and finally drive gently to let everything cool. Proper bedding lays an even transfer layer on the rotor and is the difference between a strong pedal and early judder.

Choosing Your F8x Brake Upgrade: Full Kit vs Front-Only vs Rotors

Not every F8x owner needs a $9,000 race kit. The right upgrade depends on how the car is used. A dedicated track car earns the full Alcon front-and-rear kit; a fast street car with occasional lapping is well served by a front-only kit or a two-piece rotor and race-pad refresh. Here is how the main options compare:

The Full Race Kit: Alcon Front & Rear

The Alcon 6-Piston 380x36mm Front / 4-Piston 355x28mm Rear Race Kit is a complete, balanced motorsport brake package for the F8x. Because both axles are upgraded together, front-to-rear brake bias stays predictable and you get consistent, fade-free stops through an entire session. It fits 2016-2018 M2 F87, 2019-2021 M2 Competition, 2015-2019 M3 F80, and 2015-2019 M4 F82/F83 including the 2020 M4 GTS.

The Budget-Conscious Start: Alcon Front-Only Kit

The front axle does 60-70% of the braking work, so a front-only Alcon 6-piston kit is the smartest first step for many owners. You get the same 380mm x 36mm two-piece front rotor and monobloc caliper as the full kit at roughly half the cost, and you can add the matching rear later.

Refreshing OE Calipers: Genuine Brembo Replacements

If your OE calipers are pitted, leaking, or simply tired after years of track use, genuine Brembo OE X-style front calipers restore factory performance without the cost of a big brake kit. They are a direct bolt-on for 2016-2021 M2, 2015-2018 M3, and 2015-2020 M4, and they let you pair a fresh two-piece rotor and race pad with a known-good caliper.

Off Carbon Ceramics: GiroDisc Two-Piece Rotors

F8x cars that left the factory with the M Carbon Ceramic package (red, silver, or gold calipers) face brutal replacement-rotor costs once the ceramic discs wear out. GiroDisc 400mm two-piece slotted front rotors bolt directly to those factory carbon-ceramic calipers, converting the car to serviceable, track-friendly iron rotors at a fraction of the OE ceramic price — a smart move for a CCB car that now sees real track duty.

Alcon F8x Race Kit: Pros and Cons