135i/335i Big Brake Kit Adapters for 380mm F80 Brembo

Description

Check out the Seems Legit Garage YouTube channel for install videos.
What you get is everything you need to adapt the F80/F82 M3/M4 front calipers. Calipers and rotors not included.
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.
As with everything Seems Legit Garage makes, 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.
Weights:
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- 19.9lbs
Wheel Requirements:
Wheels must have barrel of 17" or greater to clear this setup. Fits most 18" wheels.
Part Numbers:
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