SKU: 45292403332

Girodisc Rear 2-Piece Floating Rotor Set - F8x M2, M3, M4 W/ Blue Calipers

Sale price$1395.00 Regular price$1550.00
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Description

Girodisc Rear 2-Piece Floating Rotor Set - F8x M2, M3, M4 W/ Blue CalipersGirodisc is a Braking Technology Company dedicated to developing the best quality high performance braking components and solutions. The company has been in business since 2003 and is guided under the direction of company Principal Martin Meade, who spent five years as an Engineer with Porsche Engineering Services, where he played a role in developing current Porsche technology. PRODUCT INFORMATION The Girodisc system is a direct replacement for the

Girodisc is a Braking Technology Company dedicated to developing the best quality high performance braking components and solutions. The company has been in business since 2003 and is guided under the direction of company Principal Martin Meade, who spent five years as an Engineer with Porsche Engineering Services, where he played a role in developing current Porsche technology.

PRODUCT INFORMATION

The Girodisc system is a direct replacement for the OE disc. No modifications are necessary. The disc will bolt directly to the car and work with OE calipers perfectly. By upgrading your brakes with lightweight high performance replacements as opposed to a big brake kit, your factory bias is maintained as well as your ABS efficiency.

The central hat section of the Girodisc rotor is made from strictly U.S. sourced 6061-T6 aircraft specification aluminum.  The disc is made from Girodisc's own proprietary cast iron, poured in the USA and machined from start to finish in house at Girodisc.  The rotor utilizes a curved vane design, developed in racing to act as a centrifugal pump to force cooling air through the disc.

The rotor and hat have a floating mount system, which utilizes 10 high strength alloy steel drive pins, manufactured by Girodisc in the USA to their own specifications and cadmium plated for a long lasting corrosion resistance. These pins take the load from braking actions while maintaining the axial and radial float between the hat and disc. The pins are secured by class 12.9 cap screws with hardened washers. In order to keep the rotors from making noise when cold, the pins are mounted with anti-noise spring washers on the rotor side which allow the rotor to grow with heat expansion but eliminate the rattle and noise associated with floating rotors. This float also allows the rotor to self center between the pads.

Once the Girodisc system is in place, simply replace the cast iron rotor when needed.

Sold/priced per pair.


Fitment Information


This application is only for F87 M2 & M2 Competition Coupe, F80 M3 Sedan, F82 M4 Coupe and F83 M4 Convertible models, including Competition, CS and GTS, equipped with blue calipers and iron rotors. Not suitable for models fitted with silver/red M-Sport brake package (S2NH) or M Carbon Ceramic brake package (S2NK).

Girodisc Rotor Construction


The primary purpose of the Girodisc system is to reduce unsprung and overall vehicle weight. The secondary purpose is to increase the ventilation and cooling capacity of the brake disc while retaining it's original dimensions. This is accomplished by using two-piece disc construction. The central “hat” section of the disc is made from 6061-T6 aircraft specification aluminum.

The disc is made from cast iron, to the same specification and material as used by professional racing organizations. It is a curved vane design, developed in racing to act as a centrifugal pump to force cooling air through the disc. The rotor and hat have a floating mount system, which utilizes  high strength alloy steel drive pins, manufactured by Girodisc to our own specifications and cadmium plated for a long lasting corrosion resistance. These pins take the load from braking actions while maintaining the axial and radial float between the hat and disc. The pins are secured by grade 12 cap screws with hardened washers. In order to keep the rotors from making noise when cold, the pins are mounted with anti-noise spring clips on the rotor side which allow the rotor to grow with heat expansion but eliminate the rattle and noise associated with floating rotors. This float also allows the rotor to self center between the pads.


Important Questions Answered


What is required to install the Girodisc system?

The Girodisc system is a direct replacement for the OE disc. No modifications are necessary. The disc will bolt directly to the car and work with OE calipers and pads perfectly. Once the Girodisc system is in place, simply replace the cast iron rotor when needed. Some discs are larger in diameter and come with caliper spacers. If longer bolts are required, they are also supplied.

How does reducing weight of the braking system benefit the vehicle?

The Girodisc will generally weigh between 4 – 8 lbs less than the oe disc it will replace. This is due to the heavy cast iron hat section being replaced with lightweight, high strength aluminum. The mass of any vehicle requires energy to accelerate or decelerate. Reducing the vehicle mass improves acceleration, and requires less energy to be dissipated during deceleration. Rotating mass requires additional energy in order to increase or decrease its speed of rotation. Decreasing the mass of the disc has a great benefit due to reduction in rotational inertia. This will allow more of the braking force to be available to decelerate the vehicle, not the disc.

Additionally, the mass of the brake system is also unsprung mass. Reducing the unsprung mass has the additional benefit of improved suspension performance, resulting in enhanced ride and handling. Rotating masses require additional energy to vary the plane on which they turn. The lighter the disc, the quicker the response of the vehicle steering due to the reduction in gyroscopic effect/rotational inertia of the disc. As an example, compare the weight of the Ferrari 360 OE disc at 18.2 lbs, and the Girodisc at 14 lbs. The Girodisc is 4.2 lbs lighter per disc. Replacing all four discs will save 16.8 lbs of rotating, unsprung mass.

Why slotted discs?

The edges of the slots continuously clean and refresh the pad surface. This will allow the pads to have a maximized friction surface always available. Additionally, they prevent containments from collecting between the pad and disc interface. The disc is lightened, decreasing its rotational inertia. Slots prevent the formation of a water film on the disc in wet weather, maintaining the best brake response.

A note on drilled discs

Girodisc does not recommend drilled discsfor high performance applications. The rapid heating and cooling cycles will cause cracking on the friction surface of a drilled disc. The use of high friction or racing pads will exaggerate this condition. Most pad manufacturers specifically recommend that their race pads not be used on a drilled disc for this reason. Girodisc can drill discs for an additional fee,  if the customer is aware of the potential hazards of drilling the discs.

Note as example the cracking in this OE Ferrari 550 drilled disc after one track day. Also note this custom front disc of a Porsche 993 Turbo after hard use (see photos).


Please see photos attached


Should new discs and pads be bedded in and if so, how?

The answer is yes, for optimum performance, any time different friction materials or discs are introduced, a bedding procedure should be carried out.

Which direction should the discs rotate?

For maximum airflow and superior cooling, the Girodisc system uses curved vanes. For a curved vane internally vented disc, the geometry of the vanes dictates the direction of rotation. A curved vane disc must be installed with the vanes running back from the inside to outside diameters in the direction of rotation. Your discs will come with labels indicating their correct placement on the vehicle. Orienting the disc in this manner creates a centrifugal pump. The rotation of the disc causes air to be pumped from the center of the disc, through the vanes, and out through the outside diameter of the disc. This greatly enhances the disc’s ability to dissipate heat. Discs installed backwards have very limited cooling.

Models
  • 2 Series / F87 M2 (2016-2021) / M2 Competition
  • 2 Series / F87 M2 (2016-2021) / M2
  • 2 Series / F87 M2 (2016-2021) / M2 CS
  • 3 Series / F80 M3 (2014-2019) / M3
  • 3 Series / F80 M3 (2014-2019) / M3 Competition
  • 3 Series / F80 M3 (2014-2019) / M3 CS
  • 4 Series / F82 / F83 (2014-2019) / M4
  • 4 Series / F82 / F83 (2014-2019) / M4 Competition
  • 4 Series / F82 / F83 (2014-2019) / M4 CS
  • 4 Series / F82 / F83 (2014-2019) / M4 GTS


        Shipping Notes
        • Free Standard Shipping on $100+ Orders to the USA.
        • Except Preorder products are shipped in 48 hours.
        • Delivery to the USA:
        1. Standard Shipping : 3-10 business days
        • If time is of the essence, please consider selecting expedited delivery for faster service.
        Exchange/Return Notes
        • We offer a 30-day return/exchange service after receiving.
        • Final sale items are not eligible for returns or exchanges.
        • To process your return/exchange, please contact us at [email protected]
        • Please click here for more details>>> Return & Exchange Policy
        SKU: 45292403332

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        4.4 ★★★★★
        Based on 7 reviews
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        B
        Verified Purchase
        B. Hathcock
        Port Orchard, US
        ★★★★★ 5
        Aggressive chewers have met their match.
        Size: 10.5 inch Rubber Flex Tread
        We purchased this toy in 2022, it finally broke last night. Four years of rough play with 2 boxers who are aggressive chewers. They would tug together, gnaw on it for hours, and often leave it outside exposed to the elements, but this toy just kept going. It was by far their favorite toy, it kept them busy for hours. I just ordered a replacement. Well worth the money, perfect size. Highly recommend.
        WAS THIS REVIEW HELPFUL?YesReportShare
        Reviewed in the United States on April 1, 2026
        E
        Verified Purchase
        Erika Wilson
        Bozeman, US
        ★★★★★ 5
        Durable, fun, and safe for my dog
        Size: 10.5 inch Rubber Flex Tread
        I have a 10 month old, 50 lb mutt who has the musculature of a pit bull and the muzzle of a GSD. Buttercup’s favorite past-time is shredding toys into teeny tiny bits, but sometimes those bits don’t come back out of her mouth. She can’t have tennis balls, stuffies, anything with a squeaker, silicone toys, plastic toys, rubber toys with spikes or small appendages, anything with rope, or most chews & bones. She chewed her first and only $8+ XL bully stick like a corn chip. Finding indoor enrichment is a challenge. Buttercup is extremely pleased with this tire tug thingy, it is very ergonomic for both her and me to get a handle on it, it has more movement than any other toy she can safely have, and it’s very durable. After more than a week, there’s only a little bit of tread missing, which is definitely the best-case outcome with a super chewer. I think this is a good alternative to GoNut toys because it’s solid & dense while also a little bit easier & more interesting to play with, and very unlike GoNuts, this Tonka toy is very reasonably priced. I also think this it’s a good size for almost any breed of dog—I could definitely picture a little Boston or Frenchie dangling from one end. Highly recommended!
        WAS THIS REVIEW HELPFUL?YesReportShare
        Reviewed in the United States on December 20, 2024
        T
        Verified Purchase
        TasteTheRainbow87
        Massapequa, US
        ★★★★★ 5
        Dog loves it
        Size: 10.5 inch Rubber Flex Tread
        I would buy this again and again. It’s extremely durable and has held up great with my 9 month old Saint Bernard puppy. We even call it his “pacifier” because every night he grabs it and chews on it until he falls asleep. Definitely a favorite in our house!
        WAS THIS REVIEW HELPFUL?YesReportShare
        Reviewed in the United States on March 20, 2026
        R
        Verified Purchase
        Rob
        Grantham, US
        ★★★★★ 4
        Tough toy, but the yellow tire broke at the seam
        Size: 10.5 inch Rubber Flex Tread
        It was fun while it lasted and it got a lot of use, but it finally gave out after 6+/- months? Great tug toy. My dog is a 70# mutt with a strong bite and he's chewed through pretty much every other toy he's ever had. This one lasted longer than any of the others by quite a bit. He did zero chew damage to the tires, but the yellow tire in the middle broke at the seam. No tear, the seam just came undone at 90 degree angles. I'm going to look for something else this time but this wasn't bad considering how long it lasted and it wasn't very expensive. If I don't find anything tougher, I may purchase another one of these down the road.
        WAS THIS REVIEW HELPFUL?YesReportShare
        Reviewed in the United States on March 18, 2024
        J
        Verified Purchase
        JB
        Boise, US
        ★★★★★ 1
        Not for tough chewers at all!!!
        Size: 10.5 inch Rubber Flex Tread, Size: 10.5 inch Rubber Flex Tread
        5 minutes in and it's destroyed. Very disappointing.
        WAS THIS REVIEW HELPFUL?YesReportShare
        Reviewed in the United States on May 21, 2026

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