Which GiroDisc rotors do the GiroDisc Porsche 380mm Rear Replacement Rings fit?

The GiroDisc Porsche 380mm Rear Replacement Rings fit the hats of two GiroDisc rear rotors: A2-146 for the 991 GT3 and GT3 RS, and A2-155 for the 991 Turbo and Turbo S. GiroDisc lists D2-146 as the replacement ring on both of those product pages.

Will these rings work on a 991 with ceramic brakes?

No. The rings fit only GiroDisc hats, and the GiroDisc rear rotors they belong to are built for 991 cars on factory iron brakes. A car with Porsche Ceramic Composite Brakes would need the GiroDisc rotors fitted before these rings could ever be used.

What are the 991 rear ring dimensions?

Each ring measures 380mm in diameter and 32mm thick when new, with 72 curved internal vanes. GiroDisc sets the minimum thickness at 30mm, marked on the hat and on the ring edge, and the rings should also be replaced if a crack reaches the edge.

What else is needed to fit the 991 rear rings?

Nothing beyond the GiroDisc hats already on the car. Each pair includes cadmium-plated drive pins, class 12.9 cap screws with hardened washers and anti-noise spring washers. The cap screws are tightened to 60 in-lb at most so the ring keeps its float.

Why do GT3 and Turbo owners re-ring instead of buying new rotors?

The aluminum hat is the expensive, durable part of a two-piece rotor and does not wear like the iron. Replacing only the rings at minimum thickness keeps the hats in service for years and makes track use of a 991 far cheaper per season.

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Description

GiroDisc Porsche 380mm Rear Replacement Rings for 991 911 GT3 and Turbo

GiroDisc’s Porsche 380mm Rear Replacement Rings fit two GiroDisc rear rotors for the 991 generation: the GT3 and GT3 RS set and the Turbo and Turbo S set. Each ring is 380mm by 32mm with 72 curved vanes and a 30mm wear limit, cast from GiroDisc’s high-carbon iron and machined in Bellingham, Washington. The pair includes new drive pin hardware, and the anodized hats already on the car are reused. A 991 owner who has worn through the first set of GiroDisc rear rings needs nothing else to get back on track.

Fitment and Installation

The worn rings are unbolted from the GiroDisc hats and the new pair is fitted with the supplied drive pins, cap screws and spring washers, torqued to no more than 60 in-lb, or 7 Nm. Each ring is labeled left or right to keep the curved vanes turning the right way.

Features

380mm by 32mm ring with a 30mm minimum thickness
72 curved cooling vanes
High-carbon iron machined in-house
Fits GiroDisc rear hats for both the 991 GT3 and 991 Turbo
Full replacement hardware kit for two corners

What’s Included

Rear replacement rings (L/R)
Replacement mounting hardware

Applications

Porsche 911 GT3: 991
Porsche 911 GT3 RS: 991
Porsche 911 Turbo: 991
Porsche 911 Turbo S: 991

Notes

The GiroDisc Porsche 380mm Rear Replacement Rings fit only the hats of the GiroDisc 991 GT3 rear rotors and the GiroDisc 991 Turbo rear rotors; hats are not included
Cars with PCCB are not covered
The front hats of the 991 GT3 GiroDisc rotor take the GiroDisc 380x34mm front replacement rings
Stock photography may not depict the actual product

Frequently Asked Questions

Which GiroDisc rotors do the GiroDisc Porsche 380mm Rear Replacement Rings fit? The GiroDisc Porsche 380mm Rear Replacement Rings fit the hats of two GiroDisc rear rotors: A2-146 for the 991 GT3 and GT3 RS, and A2-155 for the 991 Turbo and Turbo S. GiroDisc lists D2-146 as the replacement ring on both of those product pages.
Will these rings work on a 991 with ceramic brakes? No. The rings fit only GiroDisc hats, and the GiroDisc rear rotors they belong to are built for 991 cars on factory iron brakes. A car with Porsche Ceramic Composite Brakes would need the GiroDisc rotors fitted before these rings could ever be used.
What are the 991 rear ring dimensions? Each ring measures 380mm in diameter and 32mm thick when new, with 72 curved internal vanes. GiroDisc sets the minimum thickness at 30mm, marked on the hat and on the ring edge, and the rings should also be replaced if a crack reaches the edge.
What else is needed to fit the 991 rear rings? Nothing beyond the GiroDisc hats already on the car. Each pair includes cadmium-plated drive pins, class 12.9 cap screws with hardened washers and anti-noise spring washers. The cap screws are tightened to 60 in-lb at most so the ring keeps its float.
Why do GT3 and Turbo owners re-ring instead of buying new rotors? The aluminum hat is the expensive, durable part of a two-piece rotor and does not wear like the iron. Replacing only the rings at minimum thickness keeps the hats in service for years and makes track use of a 991 far cheaper per season.

About GiroDisc

GiroDisc designs, manufactures, and sells 2-piece, fully floating brake rotors for a wide range of performance vehicles. Every major component, including the hats, rotor rings, and drive pins, is manufactured in-house at their facility in Bellingham, Washington, from domestically sourced materials. GiroDisc rotors use a proprietary high-carbon iron ring formulated for superior metallurgy and thermal performance, paired with reusable machined-aluminum hats that reduce the long-term cost of maintaining a high-performance brake system. The 2-piece floating design sheds unsprung and rotating mass while remaining street-friendly, delivering race-proven braking for track and street use alike.

Additional Information

The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.

Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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GiroDisc Porsche 380mm Rear Replacement Rings for 991 911 GT3 and Turbo [D2-146]

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GiroDisc Porsche 380mm Rear Replacement Rings for 991 911 GT3 and Turbo

Fitment and Installation

Features

What’s Included

Applications

Notes

Frequently Asked Questions

About GiroDisc

Reviews