SKU: 63415898052

GiroDisc Porsche 911 Carrera / C4 (991.1) 350mm Slotted Rear Rotors

Sale price$588.60 Regular price$654.00
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Description

GiroDisc Porsche 911 Carrera / C4 (991.1) 350mm Slotted Rear RotorsSold priced in pairs Welcome to GiroDisc! Brake rotors have long been the overlooked link in performance car braking systems. Traditional 1 piece brake rotors are heavy and retain heat, diminishing their effectiveness and adding unsprung weight that adversely affects handling. When GiroDisc was founded in 2003, we made it our mission to design and manufacture 2 piece brake rotors that would perform flawlessly at the limits. Our fully floating design


Sold/priced in pairs


Welcome to GiroDisc!

Brake rotors have long been the overlooked link in performance car braking systems. Traditional 1-piece brake rotors are heavy and retain heat, diminishing their effectiveness and adding unsprung weight that adversely affects handling.

When GiroDisc was founded in 2003, we made it our mission to design and manufacture 2-piece brake rotors that would perform flawlessly at the limits. Our fully-floating design uses tension hardware to ensure that our rotors are silent on the street, but ready to go on the track.

By specializing in this area, we can dedicate our efforts to push our engineering and manufacturing to the highest levels in the industry. Customers around the world have found success maximizing the capabilities of their existing brake systems by installing GiroDisc rotors. This often negates the need for a pricier, more complex upgrade like a big brake kit.

GiroDisc is headquartered in Bellingham, Washington, where we design, engineer, manufacture and fulfill orders on site.


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

Q: What is required to install the Girodisc system?

A: 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.

Q: How does reducing weight of the braking system benefit the vehicle?
A: 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.

Q: Why slotted discs?
A: 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.

 

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
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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]
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SKU: 63415898052

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4.9 ★★★★★
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J
Verified Purchase
JOKER
Battle Creek, US
★★★★★ 1
Sound unexpectantly blasted for no reason. It malfunctioned!
I spent hours between installation and set up! I had to return it. I turned on NET (network) to play Sirius Xm and the volume was low but after a few minutes the sound turned all the way up to maximum completely on its own? This happened at least two more times. I contacted ONKYO and was told it is clearly defective and that their is no solution to correct the problem, and that I should return it immediately! I purchased the newer model and am pleased with its performance! It’s unfortunate because the first one that had the issue with the sound really played nice, but having sound change its volume so suddenly to its full capacity was not what I expected, nor felt comfortable enough to keep as I said I was told to return it, which I did! My advice here would be to purchase the newer model, which seems to be much more stable in its performance, and the quality is excellent.
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Reviewed in the United States on November 29, 2025
B
Verified Purchase
Bossman
Lexington, US
★★★★★ 5
Absolutely Love This Receiver
The Onkyo TX‑NR7100 has completely transformed my home theater. The sound quality is rich, detailed, and powerful, and the 9.2‑channel setup gives movies and music a level of immersion I didn’t realize I was missing. Dirac Live right out of the box is a huge win — the room correction made an immediate, noticeable improvement. Setup was smooth, the interface is clean, and everything from streaming to switching inputs feels fast and reliable. It also plays perfectly with the rest of my system, and the THX certification really shows in how cinematic everything sounds. I absolutely love this receiver. It’s one of those upgrades that makes you wonder why you didn’t do it sooner.
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Reviewed in the United States on February 20, 2026
J
Verified Purchase
James Tepper
Draper, US
★★★★★ 5
Incredible 9.2 Surround receiver at an unbeatable price.
I may return at a future date to give a more complete review, but others that are much more knowledgeable about audio equipment than I have already done so. For me, the Onkyo (Onkyo TX-NR7100 9.2-Channel 8K/4K Network A/V Receiver) replaced a much older (2001) TX DS787 5.1 100 W Surround receiver that listed new for around $1050. I probably didn't pay quite that much but certainly something near $900. It was great for its time, perhaps even advanced with THX, Dolby, and other listening modes. But it didn't have: HDMI inputs or outputs, any BlueTooth capability, no hard wired or WiFi connectivity or basically any operating or connection modes that most all modern receivers have. This turned into a big problem with modern LED/LCD/OLED TVs, Alexa and other now common devices. I bought my new Onkyo TX-NR7100 from Amazon for $625. Other retailers (e.g.Best Buy) advertise it for up to $1200, so Amazon's price is outstanding. Set up was far more complicated (for me) than any previous receiver that I ever owned, mostly because there were a very large number of back panel input and output jacks, to and from the TV, as well as speaker outputs for 9.2 surround. Suffice it to say that once everything was connected properly (I made a few mistakes along the way), I was completely thrilled. The On Screen Display, completely accessible either from the front panel or the remote was far superior to anything I had ever seen before. Literally every operating parameter is accessible to the user. And I used most of them. It is also completely WiFi ready so my 150 Gbit home Wifi network lets it connect wirelessly and stream music error free. BlueTooth is also another way to connect almost any device to it for audio and audio/video playback if you connect the digital connections to and from a modern TV. It also speaks and listens to Alexa, although I must confess that I haven't played around with that much yet. This is already much longer than I had intended, so let it suffice to say that the Onkyo TX-NR7100 is an absolutely incredible receiver for an incredible price. I'd give it 8 stars if I could. JM TEPPER
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Reviewed in the United States on November 7, 2024
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Verified Purchase
Brian M.
Lowell, US
★★★★★ 5
Sounds great.
Just received my Onkyo TX-NR 7100, watched a few YouTube videos before it arrived, so set up was easy. Ran accuEQ, I am getting new front speakers so I’ll wait to run Dirac. After accuEQ, I still had to make a few adjustments, to the speaker levels and especially the sub. It set my subwoofer way too low. As of right now having no problems with Bluetooth. I’ve only listened to music so far, can’t wait to watch a movie. For now I have a 5.1.2. System, getting new fronts, the Klipsch r51-m’s will go to the rear surround and Klipsch r41-m’s will be my height speakers in a 5.1.4 system. So far loving this avr. Update 2: Just calibrated with Dirac for the 6th time. They tell you if you sit in a recliner, reclined measure with it reclined. Well I measured with the chair in its upright position. It makes a huge difference I hear the surrounds much better. Btw I listen to all channel stereo, I know audiophiles say it sucks, however I listened to 2 channel stereo for 20 years, when there was nothing else. I didn’t buy a 9 channel avr to listen to 2 channel stereo. Like Randy the cheap audio man says “ audiophiles aren’t always right. If it sounds good to you, that’s all that matters.” So try calibrating in the upright position, or if you sit on a stationary chair or couch, try positioning the mic slightly forward of your listening position. It makes a huge difference. Hope this helps, enjoy. Update: Ok bought Klipsch rp-600m speakers for the front with 52c center. 51m surrounds, 41m rear heights. Polk owm3 front heights. Why Polk? Lighter easy to hang and as height speakers they are only there for atmos. Ran Dirac live, the application does what it would take several hours to make it sound like it does, if I even could get it to sound so good. Apple TV 4K with my Hisense U8K. The google tv interface is ok, but Apple TV is faster and easier. The Onkyo 7100 is a gem, runs pretty warm but I have it out in the open. If you are going to put in a cabinet I suggest a fan. Very happy with the whole system.
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Reviewed in the United States on January 11, 2025
A
Verified Purchase
Amazon Customer
Fort Morgan, US
★★★★★ 5
Handles the power
Size: 5FT, Style: 8AWG
Used for leads to handle high Amperage. Replaced cheesy 12 gauge leads that came with the unit
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Reviewed in the United States on January 28, 2026

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