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]
Easy to assemble, does the job, material is shiny nylon and shows creases, minor defects, sloppy
Size: 3 Panel 12FT W, Size: 3 Panel 12FT W
The Siebwin room divider is a good idea, and for the price, it mostly delivers on the intended functionality. I ordered the 12 foot, 3-panel version mainly to hide an unfinished basement storage area that had become an eyesore. It works well for that purpose and gives the space a cleaner appearance without spending the kind of money that more decorative dividers or custom partitions cost. If you need something temporary, portable, or mainly functional, this is a viable option.
There are a few limitations that became obvious during setup and use. The first thing I noticed was that the weld quality on some of the metal poles is fairly sloppy. Once the cover is installed, you do not really see it, but up close, it does not look especially refined or professional. The blackout material also is not a matte canvas style fabric as I expected. It has more of a shiny nylon appearance, and the creases are fairly visible. Being that it’s more of a nylon, I’d be hesitant to try steaming it to remove the creases. However, the creases do not matter if you are using it in a basement, dorm, or shared room, but for photography, video work, or a professional office setting, the appearance could be disappointing. The fabric is thick enough, though. It blocks visibility well enough, but strong light behind it still shows through to some extent, nothing deal-breaking. Also, my fabric appeared to be slightly defective. The hook and loop strip on one of the bottom sections was off-center and couldn't be totally attached because it was lined up with one of the legs. I originally hoped to use this as a video backdrop, but I will probably end up replacing the fabric with a proper green screen or canvas material while continuing to use the frame itself. For now, it does a good job of covering my basement junk.
Assembly was actually easier than I expected and took roughly 15 to 20 minutes. The longer vertical poles are tethered together similarly to tent poles, which made setup straightforward and fairly intuitive. The shorter horizontal pieces slide and snap together to the top and bottom of the vertical assembly. After each section is assembled, the divider panels connect together with metal plates and two knurled screws (at the top and bottom), so no tools are really required. A few screws were difficult to start because paint had gotten into the threads, but once they caught, they tightened down normally. The feet install with similar knurled fasteners and help keep the divider reasonably stable. One thing to watch for during setup is the fabric orientation. There is one arrow indicator in the middle of the fabric to indicate up. However, if you need another indicator, the smaller hook and loop strip goes on the bottom while the longer strip goes on top. I realized mine was upside down right before finishing and had to redo it. I wasn't difficult to redo, despite the defect in mine.
The overall design is practical and easy to move around. I do like that the panels can fold and bend into different shapes depending on the space. The widened feet help stability, although when trying to stretch the fabric tight, I noticed the poles sometimes wanted to overlap slightly at the joints. Tightening everything helped somewhat, but it still happened occasionally. The divider feels adequate for normal indoor use, though I would not expect premium durability or luxury-level fit and finish at this price point. The entire device can also be easily disabled and stored in a tote if you need it completely out of the way. It comes with assembly instructions, but even if you didn’t have them, it’s easy to build without them (save a mistake or two).
In terms of value, I think the Siebwin divider mostly matches its price. Around $100 gets you a large freestanding partition with decent usability and easy assembly, but there are compromises in materials, appearance, and refinement. The defects are also off-putting, but hopefully you won't have them. Higher-end room dividers can easily cost two or three times more, so some of the tradeoffs are expected. I also noticed cheaper alternatives online, but based on the quality here, I suspect those would probably have even more issues. For practical home use, temporary privacy, hiding storage areas, or separating shared spaces, this is a good option as long as expectations stay realistic.
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Reviewed in the United States on May 18, 2026
T
Trendy Tales
Omaha, US
★★★★★ 3
Works well but takes up more space than expected
Size: 2 Panel 8FT W, Size: 2 Panel 8FT W
This room divider does the job for creating a little extra privacy and was easy enough to set up. The panels feel decent quality and the wider feet help keep it more stable than some cheaper screens I’ve tried. My only issue is that it takes up a bit more room than I expected, especially with the feet sticking out. It’s still portable and folds away nicely, but definitely measure your space first. Overall it works well for separating a room or blocking off an area temporarily. i wish it came in other colors
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Reviewed in the United States on May 26, 2026
K
Katrina Rhodes
Massapequa, US
★★★★★ 5
Nice divider, serves it's purpose well!
Size: 3 Panel 12FT W
This room divider worked out very well for what I needed. I wanted a simple way to create a little more privacy and separation in a larger room without doing anything permanent, and this divider was an easy solution. The panels provide good coverage, and the black color gives it a clean, modern appearance that blends in nicely with different décor styles.
Assembly was fairly straightforward, and once set up, the wider feet helped keep the divider stable on the floor. I was especially happy with how flexible the panels are to arrange. You can keep it mostly straight, angle it around furniture, or create a more enclosed private space depending on the layout you need.
The material allows light to filter through slightly while still offering a noticeable sense of privacy. I’ve used it for separating a workspace area, but it would also work well in bedrooms, apartments, dorms, studios, or shared living spaces. Another plus is that it can be folded and moved without too much effort when you want to change the setup.
Overall, this divider delivers a good balance of functionality, portability, and appearance. It’s a practical option for anyone needing temporary room separation without installing permanent walls or curtains.
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Reviewed in the United States on May 26, 2026
J
Jamie K.
Bozeman, US
★★★★★ 5
Perfect for Adding Privacy to a Piano Studio
Size: 2 Panel 8FT W, Size: 2 Panel 8FT W
I Ordered the 2 Panel version which is way too big for my needs... that's on me. So keep in mind that the picture shows a fabric made for two panels only being used on one and hence it is not pulled tight; it would pull tight and not be so wrinkly if it was set up properly as two panels. The metal pools that make up the panels seem to be well made, stable, and of good quality. They were very easy to put together and they stand up tall with plenty of height. The appearance of it with the fabric on it isn't as elegant as it could be, but it still looks good enough. The material is plenty solid, not allowing light through it, and thereby making a solid barrier. I am using it to block the view out the studio door when a student is sitting at the piano to avoid distractions from the hallway. It will allow a student to enter the studio with our distracting the student who is at the piano.
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Reviewed in the United States on May 18, 2026
J
Just Me
Los Angeles, US
★★★★★ 5
Room Divider That Gives Instant “This Is a Separate Space Now” Energy
Size: 3 Panel 12FT W
The Siebwin 3 Panel Folding Privacy Screen is surprisingly effective at changing the feel of a room without requiring construction, commitment, or somebody yelling about load bearing walls. The 12 foot width gives a substantial amount of coverage, making it useful for creating privacy, dividing open areas, blocking visual clutter, or setting up temporary sections within larger rooms. This saved us a ton of time and money in our new studio and enabled us to create a kitchen and office in one room.
The wider feet make a huge difference because flimsy room dividers that collapse every time someone exhales too aggressively are deeply annoying. This one feels more stable and grounded once positioned. The folding design makes it easy to move around or adjust depending on the space, and it folds down relatively compactly when not in use. It is basically the introvert curtain wall of dreams.
The material has a clean, neutral look that blends well into different room styles without screaming “temporary office cubicle panic.” It works well for apartments, studios, shared spaces, dressing areas, or simply hiding the mountain of chaos you swear you are going to organize tomorrow. Practical, portable, and refreshingly easy to use without turning setup into a three hour emotional event.
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