M3/M4 Big Brake Kit
This big brake adapter kit allows you to use the OEM F80 M3/F82 M4 Brembo Calipers and 380x30mm rotors on your non-M E8x or E9x. Fits all 128i, 135i, 328i, 330i, 335i, Xi models, etc. This kit includes everything you need, including special fasteners. Hose kit is optional, but recommended. Stoptech rotor upgrade really brings it all together to become an amazing looking and capable track package.As with everything we make, this kit is designed (including FEA) and manufactured here in the USA. They are CNC machined from billet 4140 steel, gold zinc coated, and have a safety factor of 6 so they are prepared to take whatever you can throw at them.Critical to designing a big brake kit is not only the "bigger is better" mentality, but piston size, rotor torque, and brake bias which are all important primary factors. Without changing your brake booster or master cylinder, this kit changes your brake bias by less than 1%. This ensures that the vehicle will retain a good initial bite, balance, and will have consistent pedal travel just like OEM.The M3 & M4 calipers are a lightweight 2-piece design with stainless steel pistons. The stock 135i 6-pot Brembo is notorious for having the ceramic pistons crack after only a few track sessions. Even after you spend a bunch of money on new pistons and seals, the OEM brakes still have trouble slowing down these vehicles with just a small 338mm iron hunk they try to call a rotor that does not shed heat well. No matter what we did on our 135i, we could not get the brakes to not overheat. With this kit you are adding over 40mm of surface area of the rotor and using an aluminum rotor hat which cools down dramatically faster. On top of that, we are still cutting weight from the system. See list of weights below. A potential loss of 2.4 pounds per corner of unsprung mass, while increasing the braking potential greatly. Truly a win/win upgrade.
- 135i Brembo Caliper – 11.4lbs
- 135i Rotor – 22.5lbs
- M3/M4 Caliper – 10.7lbs
- M3/M4 OEM Rotor – 24.8lbs
- M3/M4 Stoptech Trophy Aerorotor – 23.8 lbs
- M3/M4 Racing Brakes Rotor- 19.9lbsWheel Requirements:
Wheels must have barrel of 17" or greater to clear this setup. Fits most 18" wheels.
- Calipers: 34116799469 and 34116799470 can be purchased new in grey/blue/orange/yellow/red or can be sourced for a junkyard for cheap. Found on F30's, F80, and F82's.
- OEM Rotors: 34112284810 and 34112284809
Terms and Conditions
Due to the intended use of high performance products, Seems Legit Garage, LLC. ("SLG”) products and each part thereof, are sold "AS IS” and with all faults. To the fullest extent allowed by law, SLG Racing Products makes NO written, oral, expressed, or implied statement of warranty or guarantee on any product or part sold. SLG will not be liable for any direct, indirect, incidental, consequential, or special damages, including but not limited to, damage, injury, loss of life, loss of property or equipment, loss of profits or revenue, or claims from any individual or entity arising from the use of any SLG product.
RACING IS A DANGEROUS ACTIVITY AND PURCHASERS OF SLG PRODUCTS ACKNOWLEDGE THE INHERENT RISKS ASSOCIATED. SLG MAKES NO REPRESENTATIONS THAT ITS PRODUCTS CAN REDUCE OR ELIMINATE ANY SUCH RISK. SLG products are NOT FOR STREET, HIGHWAY, OR AIRCRAFT USE and are intended ONLY for race vehicles operated on closed-course facilities or race tracks with appropriate supervision of qualified technicians or mechanics to ensure that the safety needs of the race driver and others are met. SLG products could be combined with other products or parts which may not be suitable and could adversely affect performance of other race parts or the vehicle. The user shall determine the ultimate suitability and safety of the product for its intended use, and the user assumes all responsibility and risk in connection therewith.
Remove brake hoses either at the caliper if you are reusing the original hoses or at the body if installing new hoses
Remove original calipers and rotors
Clean knuckle assembly of dirt and loose rust
Install brackets to each caliper using the Zinc-Coated Allen Head screws and red Loctite: Torque to 70 ft/lbs
Install 380mm F8X M3/4 rotor using the included security fastener
Bolt caliper and bracket assembly to the knuckle using the included flanged hex-head bolts and washers: Torque to 70 ft/lbs
Attach brake hose and bleed brakes