$595.00 USD
$595.00 USD








The MMX Performance 2-piece floating rear rotor set is a direct bolt-on upgrade for the factory rear discs on the G80 M3, G82/G83 M4 and G87 M2, provided your car came with the factory iron brake setup. It replaces the OE one-piece units with a true 2-piece floating design that runs cooler, weighs less, and resists the warping and judder that high-temperature track use can cause on stock rotors.
The 370mm x 24mm rotor rings are paired with separate hats so the ring can expand radially and axially under heat, instead of fighting against itself the way a one-piece rotor does. That floating construction is what dramatically extends pad and rotor life under repeated heavy braking, and is what allows MMX to engineer larger, more efficient directional cooling vanes inside the rotor casting, increasing cooling efficiency by up to 30% versus OE.
For G8X M-Cars driven hard, the rear axle is where you feel the OE limits first under sustained track use, heat builds up faster on the smaller rear discs, and the consequence is uneven pad wear and a soft pedal late in a session. The MMX rear pair addresses both: lower steady-state temperatures, more even pad wear, and consistent rear bias session after session.
The rotor face is slotted (J-hook style) to evacuate gas and pad material under heavy use, and each pair is supplied as left and right-handed directional units so vane geometry is always optimized to the direction of rotation. Bolt-on with no caliper, bracket, or pad changes required.
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$595.00 USD
$595.00 USD
This product can expose you to chemicals such as lead and lead compounds, which are known to the State of California to cause cancer or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
For a complete list of chemicals known to cause harm, visit https://www.p65warnings.ca.gov/chemicals.
Under the federal Clean Air Act (42 U.S.C. §7522(a)(3)), it is illegal to manufacture, sell, install, or use any part that defeats or alters a motor vehicle’s emission control system for use on public roads. Unless a product has received an Executive Order (EO) from the California Air Resources Board (CARB), it is not legal for use or installation on any pollution-controlled vehicle driven on public highways.
Some states have CARB-equivalent or independent emissions laws. Customers are responsible for verifying local regulations before purchasing or installing emissions-related products.
All performance, racing, or competition parts sold by this company are intended solely for off-road, closed-course, or competition use on vehicles that are never registered or used on public highways.
Kies Motorsports, LLC sells and markets these products for lawful use only. We do not condone or authorize the use of emission-control defeat devices or any modification that violates the Clean Air Act or state regulations.