M3/M4 Brembo Brake Upgrade

Updated: Mar 25

As power increases it is important to not undervalue stopping power. The E8x, E9x or F3X platform have insane performance potential, but since they weren't an "M" model they lack certain things which can help increase control and performance; two examples being a limited slip differential and powerful brakes. With our adapter plates you can harness the braking potential of the enormous Brembo's used on F8x series M3/4 vehicles.

Front Kit: https://www.seemslegitgarage.com/product-page/m3-m4-big-brake-kit

Rear Kit: https://www.seemslegitgarage.com/product-page/m3-m4-rear-big-brake-kit

Install & Review (Independent) https://www.1addicts.com/forums/showthread.php?t=1905900

Whether roll racing your N5x/B55 monster or going for faster times at the road course, these brakes are an amazing upgrade. Don't take my word for it, watch Robert Kubica, F1 legend, put them to work at the Nürburgring Nordschleife below using completely stock calipers with upgraded pads.


This kit includes everything you need; from hardened steel adapter plates to custom fasteners not available anywhere else. As with everything we make, this kit is engineered (including FEA) and manufactured here in the USA. The adapter plates are CNC machined from heat treated 4140 steel and gold zinc coated. The custom hardware is made on the CNC lathe, sent to heat treatment, and then also zinc coated for protection and good looks.

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. From doing the math and testing it ourselves, this kit will not throw your brake balance out of whack to ensures that the vehicle will retain good initial bite and have consistent pedal travel just like OEM. If tracking your vehicle hard, consider upgrading to a E9x M3 master cylinder for a harder pedal.

The M3 & M4 and M-Performance calipers are a lightweight 2-piece design with stainless steel pistons. They are much better designed than the 135i 6-pot Brembo which is notorious for having the ceramic pistons crack during track laps, or the cheap slider-style single-piston calipers on the 335i. Even after you spend a bunch of money on new pistons and seals, the OEM brakes still have trouble consistently slowing down these vehicles with such a small rotor that overheats. No matter what we did on our time-attack 1M clone, we could not get the brakes to stop fading at the track.

This big brake kit allows any Non-M E8x/E9x to install these much more capable brakes. Compare the factory front 135i 338x26/335i 348x30mm 1-piece rotors to the M3/M4 380x30mm 2-piece rotors. The rear upgrade also impressive, moving the 135i 324x22/335i 336x22mm 1-piece rotors to massive 370x24mm 2-piece rotors. The increased rotor size gives this brake package much more thermal capacity. This helps your brakes stop better, for longer. With the front and rear kit on our 650hp 1M clone we no longer have any fading issues at the track.

Wheel Requirements: Wheels must have barrel of 17" or greater to clear this setup. Fits most 18" wheels, using spacers also helps. To measure this, just take your wheels off and measure across the section where the wheel contacts the hub.

Which kit is right for you:

Depending on what car you have, you'll need a different combination of parts.

E8x Non-m (128i,135i, etc): The most simple. Using our front and rear adapter plate kits you can simply bolt on the brake package and go.

E9x Non-M (325i, 335i, etc): More difficult, but still totally doable. The fronts are a simple bolt on upgrade using our adapter plate kit. The rears will either need you to change to E9x M3 knuckles and use the spacer plate option, or make your car 10mm wider on each side by changing your hubs to those on the 135i and use our rear adapter plate kit. We do not recommend shaving down the knuckle as seen online. Changing the rear hubs is basically the same as replacing your wheel bearings. If you have a LCI E90 you have a weird knuckle and unfortunately need to change the rear knuckle to either 135i complete knuckles, non-LCI E90 335i knuckles, or M3 knuckles.

M Models (1M and M3): Due to the same reason we need to change the rear hubs on the 335i, rotor overhang makes mounting these brakes to the factory front knuckles impossible. To adapt the fronts, swap to F8x knuckles to use their brakes. To adapt the rears, all you need is our spacer plate option.

F3X Non-M: Front brackets let you mount the M-performance calipers and 380mm rotors right to your standard front knuckles. Rear kit still in the works,

OEM Part Numbers:

M3/M4 Front Calipers: 34116799469 and 34116799470. Can be purchased new or can be sourced for a junkyard for cheap. Front calipers are marked 370/380 in the casting on the back, not the same as standard F30 calipers.

M3/M4 Rear Calipers: 34216799461 and 34216799462, also found on F30 M-Performance vehicles.

Front Rotors: 34112284810 and 34112284809

Rear Rotors: 34212284811 and 34212284812

Conversion Rear Hub : 135i/335- 33416771082 128i/32X- 33416771081

Wheel Bearing: 135/335i- 33416775842 128i/32xi- 33416762317

E9x Rear Knuckles: 33302283541 and 33302283542

F8x Front Knuckles: 33416762317 and 31212284002

Install Videos

Front Bracket Instructions

M4 BBK Instructions (1) (1)
Download PDF • 344KB

Don't wait, order yours today!

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