Girodisc Rear Replacement Rotor Ring Set - E9x 335iGirodisc 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 Need new rings for your Girodisc 2 Piece Floating
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
Need new rings for your Girodisc 2-Piece Floating Rotor Set? We got them. Rings come complete with all new hardware and full instructions for re-assembly; but if you choose you can send us the hats and we will do all the re-assembly and turning of the rotors for only the cost of shipping.
This service is available for the life of your rotors. Price is for a pair of rings and 2 hardware kits. Additional hardware kits are available separately upon request.
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).
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.
My Insignia NS-STR514 suddenly died after a year of glorious sound (device still turned on, switch inputs, etc, just no sound), and I had to find another stereo receiver to replace it. Yamaha seemed to be a pretty popular brand, especially among musicians and home theater enthusiasts, so I figured I couldn't go wrong. Wrong.
From the minute I hooked this receiver up I noticed a significant drop in power, range, and overall quality. This device is advertised as having the same 100w of power per channel, so this is really surprising for a major brand. I used to have to turn the Insignia up to 20, but this device has to be turned up to 44 to get the same loudness. When you do get this device cranked up enough to hear something, the sound is very flat. There's no other way to describe it. There's no range. Even if bass cranked to max you can barely hear it. The treble is weak, flat, and distorts at high volume. This device is literally making my stereo speakers that cost $300.00 each sound like a boom box from the 90's. I was considering upgrading my turntable to a higher quality one, but now, what's the point?
On the flip side, the sound is clean, crisp. But man oh man is it flat. These days I mostly listen to music on high grade headphones and watch movies and streaming on my projector so it's not a huge loss (high fidelity sound on video games and movies isn't a huge deal to me), but don't buy this for your entry-level audiophile needs. There's got to be better options out there than this. The weak bass especially is unforgivable.
*Update 04/25/17*
My wife finally grew so tired of this piece of junk that I got rid of it and bought another Insignia Stereo Receiver. Unreliable as it is (dead after 2 years) it's still better than this garbage.
The bass response is absolutely horrible, and the neighbors started complaining about the "booming". That's pretty much the only bass you get from this device. A loud, cheap-sounding thumping. The frequency response of this device is so poor, and the sound so thin and tinny, that even my wife couldn't stand it! Do yourself a favor and avoid this one.
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Reviewed in the United States on February 15, 2017
J
Verified Purchase
James Jeffries
Grantham, US
★★★★★ 5
Excellent purchase
Style: R-S202BL, Configuration: receiver only
Good looking stereo and everything works perfectly, excellent reception and all the music is very clear at any volume (only went up to 55 out of 99).
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Reviewed in the United States on April 4, 2026
B
Verified Purchase
Brooke T
Whiting, US
★★★★★ 5
Great quality wire for any automotive or 12 volt wiring
Size: 16 AWG-100 ft
This GS Power 16 gauge wire is excellent quality for any automotive wiring project. The copper is true OFC pure copper, not copper clad aluminum. It’s flexible, easy to route, and holds up well without the insulation feeling cheap or brittle.
I have used it for automotive accessory wiring and some 12V equipment projects and it handled everything perfectly. The wire pulls cleanly, solders well, and the insulation thickness gives it a durable feel without being overly bulky.
If you need dependable wire for automotive, marine, RV, audio, or general electrical projects, this is a great buy. I would absolutely purchase it again.
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Reviewed in the United States on May 9, 2026
R
Verified Purchase
REEK
Charlottesville, US
★★★★★ 5
Real copper
Size: 16 AWG-100 ft
Good quality. Copper wire
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Reviewed in the United States on May 20, 2026
D
Verified Purchase
Duane
New York, US
★★★★★ 5
Quality all copper wire
Size: 16 AWG-100 ft
True16 Gauge pure copper wire
Quality wire with a high strand count
Nice insulation not overly stiff or too soft
Expect I will be buying more as it is a good value for the $
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