Girodisc Front 2-Piece Floating Rotor Set - E46 M3, E85/E86 Z4MGirodisc 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 These Girodisc 2 piece rotors are a direct
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
These Girodisc 2-piece rotors are a direct replacement for the E46 M3 345mm rotor found on Competition Package (ZCP) and CSL models. Weighing in at 17.5 lbs per rotor versus 19 lbs per factory rotor, these fully floating assemblies help shed unsprung weight and rotating mass from the front axle of the vehicle.
The rotor rings are machined from a proprietary casting made of high-carbon steel formulated to Girodisc’s specifications. This superior metallurgy results in a rotor that holds up better, and the 48 curved vanes act as a centrifugal pump pulling air in through the hub to effectively cool the rotors under hard use. The 2-piece design means a reusable hat which can be attached to new rings (part number D1-012) when they need to be replaced.
All major components including the hats, rotor rings, and drive pins are manufactured in-house at Girodisc's facility in Bellingham, WA from domestically sourced materials. The hat is made from 6061-T6 aluminum and coated in a black anodize finish. The drive pins are made from a high-strength steel alloy and cadmium-plated for corrosion resistance. All rotors are assembled with spring clips and Belleville washers for race-ready float while also being street-friendly with no noise from loose hardware.
Our E46 M3 rotors have been designed with common aftermarket caliper setups in mind, in addition to the stock sliding calipers available on ZCP and CSL cars. These setups include the Brembo calipers from both the Porsche 996 and Megane RS swaps.
Diameter: 345mm Thickness: 28mm Weight: 17.5 lbs per rotor assembly
The minimum thickness at which we recommend replacing these rings is 26mm. We also recommend replacing them if a crack leads to the edge of the ring.
Sold/priced per pair.
Fitment Information
This application is only for E46 M3 Coupe and Convertible, E85 Z4M Roadster and E86 Z4M Coupe models fitted with the ZCP or CSL braking system.
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 doesnotrecommend 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).
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
3 Series / E46 (1998-2006) / M3
3 Series / E46 (1998-2006) / M3 CSL
Z Series / E85 / E86 Z4 (2002-2008) / Z4M
Shipping Notes
Free Standard Shipping on $100+ Orders to the USA.
Except Preorder products are shipped in 48 hours.
Delivery to the USA:
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]
Good book, but you know the usual has its fluff, but that’s all Robert Green books. However, the stories are unmatched and if you have a vivid imagination, you’ll be able to understand and comprehend what’s going on ,it’s lovely.
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Reviewed in the United States on May 28, 2026
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Verified Purchase
Durell Ball
Lowell, US
★★★★★ 4
Different, but in a good way
Format: Paperback
I have read all of Robert Greenes previous books, and I always walked away in amazement. I would see the negative reviews those books received, but I would always ignore them and thank God that I did. That compelled me to buy this book once I saw it was released and once again, the negative review bugs are back out. Normally, I wouldn’t write a review on a book because I would rather the reader form their own opinion. This book is different, and I would like to address this for anyone who is a Robert Greene fan or in the process of becoming one.
This book is exactly what every human alive needs to read, which is why I am writing this review to stop the second guessers. It focuses on how our emotions are destructive and how we must be careful about how freely we let them out now. Yes, the style is different from his past books. He goes into narratives about the different emotions, what they can do, and how we can control them while occasionally touching on how they played out in history. For many fans of his previous books, this can be disappointing as we are used to reading thrilling tales throughout history and how they play into the law he is explaining in that chapter with side bar quotes of knowledge from historic figures. I understand why he could not take that approach with this book, as he wanted to focus more on explaining the emotions on a psychological level instead of a historical one.
Is there entertaining and historic tales in the book? Yes, somewhat but nowhere near like his past books. I ask that you open your mind to this book and allow your knowledge to grow in a world where emotional control is decaying. Like he said in this book, don’t let your emotional impulses cloud your judgement. Step back, take a second, reassess and approach this book with a clear mind. You will thank me for it.
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Reviewed in the United States on May 31, 2020
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George Gutierrez
Omaha, US
★★★★★ 5
A must read for all young and old, although, the younger, the better!
Format: Kindle
Simply fabulous! The blend of great concepts, beautifully descriptive stories, insightful analysis, and fascinating narration made it a truly engaging experience.
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Reviewed in the United States on March 9, 2026
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Jo Jo H.
Waukegan, US
★★★★★ 5
In-depth and comprehensive
Format: Kindle
This book was so full of information about the human animal. Is the only wish I had this information earlier in my life. I wish my kids would read it, and perhaps they will. It's very in depth and leaves me reflecting on how I want to change some of my thinking and behaviors like no other book I've read. I wish I belonged to a book club just to discuss it with other readers!
I don't necessarily agree with everything that the author states. But it was a most thought provoking book and I read allot of books! Allot of work went into the writing of this book. Near perfect editing which I appreciated. I am a big fan of human psychology and it held my interest and kept me up too late not wanting to put it down!
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Reviewed in the United States on February 20, 2026
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F. Collins
Port Orchard, US
★★★★★ 5
Kubrick’s revelatory swan song is full of hidden meanings
An underrated masterpiece, Eyes Wide Shut is a gem layered with meaning. A semi-autobiographical sensibility permeates given the parameters of its production. It’s immaculately shot, edited and designed and offers two central performances from the then married Tom Cruise and Nicole Kidman. Given its theme, their subsequent divorce reflects back on the choppy waters faced by their characters Bill and Alice Harford.
The result is a dream logic of coincidences that ensnare a married couple in self doubt and sexual angst. They live a fairly privileged life in a Manhattan apartment but after a Christmas party at a huge mansion owned by an elite acquaintance, the relationship begins to unravel when both are confronted by the consequences of their projected desires. This prompts the husband Bill on an odyssey through a night time New York and an escalating series of encounters as his wife’s confession about an infatuation with another man eats away at his own inner, unfulfilled desires.
It’s a dark/light solstice of a film, as man and wife chase fatalistic hidden desire, their marriage subject to dissolution and they plunge through a dark night of the soul and emerge into a morning of earnest confession and much soul searching.
In the end, it’s a fascinating watch. Quite revelatory given my initial reception to it many decades ago. But that’s Kubrick for you. It’s essential to revisit his films. Beautifully presented in 4K by Criterion, it asks us to take ownership of our inner desires, to confront them with honesty and discern what is merely a dream from the reality around us. And no, it’s not the erotic thriller the marketing promised. Another desire thwarted or a deliberate obfuscation of the intense psychological drama it really was?
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