AP Racing Four Piston Rear Caliper Kit - BMW E46 M3 2001-2006

The AP Racing Competition Caliper Kit replaces the rear calipers on the 2001-2006 BMW E46 M3 with a pair of AP Racing CP5144 four-piston calipers. It is a caliper-only kit: it bolts up with the factory rear discs, so an E46 M3 that already has a front big brake kit can get matching rear performance without buying new rotors.

Why upgrade the rear

Once the front brakes are upgraded, the single-piston factory rear calipers on the E46 M3 become the weak link. They flex under heat and fade sooner, which moves the brake balance around during a session. The CP5144 calipers are far stiffer than stock and hold larger pads, which raises the thermal capacity of the rear axle and improves fade resistance in long track sessions. Pedal feel gets firmer and more consistent from lap to lap. Piston sizes were chosen for proper brake bias and to work with the factory master cylinder and ABS system.

Made to pair with a front kit

This rear kit was developed to complement the AP Racing by Essex front Competition kits for the E46 M3. It also runs with the OEM rear discs or other aftermarket rear discs. The calipers use the common CP5100 pad shape, which is made in a wide range of race compounds, so replacement pads are easy to find. Spiegler stainless lines and all mounting hardware are included.

Features

• Pair of AP Racing CP5144 four-piston rear calipers
• Stiffer calipers with larger pads for better fade resistance
• Works with OEM rear discs
• Common CP5100 pad shape
• Spiegler stainless lines and mounting hardware included
• Optional pads can be added at checkout

What's Included

• L/R calipers
• four 10mm washers
• four 10mm locknuts
• four socket-head mounting bolts
• two anti-rattle clips
• one pair Spiegler stainless steel brake lines

Brake pads and discs are not included; the kit reuses the OEM rear discs.

Specifications

Fitment notes

Fits the 2001-2006 BMW E46 M3, including the Competition Package. Supply is limited to stock on hand and the kit cannot be backordered, so call to confirm availability. Wheels that clear the factory rear brakes are expected to clear this kit; call us if you run an unusual wheel.

Fitment