Which cars use the GiroDisc Porsche 390mm Rear Replacement Rings?

The Porsche 390mm Rear Replacement Rings serve the GiroDisc A2-154 rear iron conversion on the 991 and 992 GT3, the GT2 RS and the GT4 RS. The car must already run those GiroDisc rear hats, since the rings bolt to nothing else.

Do these rings fit the factory PCCB rear rotors?

No. They are iron rings designed for the aluminum hats of the GiroDisc rear conversion. Factory carbon-ceramic assemblies, factory two-piece hats and other aftermarket hats are not compatible, so the complete A2-154 rotors need to be installed on the car first.

How is rear ring wear measured?

Measure each ring at several points around the friction face and compare the reading with the minimum thickness marked on the hat and ring edge. Replace the pair when either ring reaches that figure, or right away if a crack reaches the edge.

Is new hardware included with the rear rings?

Yes. GiroDisc supplies replacement mounting hardware with every pair of rings, so the old fasteners are retired with the worn iron. Torque the cap screws to 60 in-lb at most, because overtightening stops the ring from floating as designed, so use an inch pound torque wrench.

How long does a rear ring change take?

With the rotor off the car it is a short bench job. The cap screws are removed, the worn ring comes off the hat, and the new ring is fitted with the supplied hardware. Most owners can complete both sides in an afternoon with hand tools.

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Description

GiroDisc Porsche 390mm Rear Replacement Rings for 911 GT3, GT2 RS and Cayman GT4 RS

GiroDisc’s Porsche 390mm Rear Replacement Rings are the wear part for the A2-154 rear iron rotor conversion, which takes the PCCB rear discs off the 991 and 992 GT3, GT2 RS and GT4 RS. Each 390mm ring is cast from GiroDisc’s proprietary iron, poured in the USA and finished in Bellingham, Washington. They come in pairs with new hardware and bolt to the hats already on the car. Rear rings outlast the fronts on most cars, so a pair on the shelf covers several seasons of track work.

Fitment and Installation

Each ring mounts to the GiroDisc A2-154 rear hat with the hardware supplied, and the worn ring is discarded. The rings suit GiroDisc hats alone, not factory PCCB assemblies, factory two-piece hats or other brands. Left and right rings are labeled so the vanes pump air outward, and the cap screws go in at no more than 60 in-lb (7 Nm).

Features

390mm diameter for the GiroDisc Porsche rear iron conversion
Proprietary iron cast in the USA
Machined in-house in Bellingham, Washington
Directional curved vanes for rear cooling
Supplied in pairs with replacement hardware

What’s Included

Rear replacement rings (L/R)
Replacement mounting hardware

Applications

Porsche 718 Cayman GT4 RS: With GiroDisc A2-154 rear iron conversion
Porsche 911 GT2 RS: 991 with GiroDisc A2-154 rear iron conversion
Porsche 911 GT3: 991 and 992 with GiroDisc A2-154 rear iron conversion

Notes

The Porsche 390mm Rear Replacement Rings fit the hats of the GiroDisc 991 and 992 GT3, GT2 RS and GT4 RS rear iron rotor conversion
Confirm the hats on your car are GiroDisc A2-154 before ordering
Hats are not included and stay on the car
Front service uses the GiroDisc Porsche 410mm front replacement rings
Stock photography may not depict the actual product

Frequently Asked Questions

Which cars use the GiroDisc Porsche 390mm Rear Replacement Rings? The Porsche 390mm Rear Replacement Rings serve the GiroDisc A2-154 rear iron conversion on the 991 and 992 GT3, the GT2 RS and the GT4 RS. The car must already run those GiroDisc rear hats, since the rings bolt to nothing else.
Do these rings fit the factory PCCB rear rotors? No. They are iron rings designed for the aluminum hats of the GiroDisc rear conversion. Factory carbon-ceramic assemblies, factory two-piece hats and other aftermarket hats are not compatible, so the complete A2-154 rotors need to be installed on the car first.
How is rear ring wear measured? Measure each ring at several points around the friction face and compare the reading with the minimum thickness marked on the hat and ring edge. Replace the pair when either ring reaches that figure, or right away if a crack reaches the edge.
Is new hardware included with the rear rings? Yes. GiroDisc supplies replacement mounting hardware with every pair of rings, so the old fasteners are retired with the worn iron. Torque the cap screws to 60 in-lb at most, because overtightening stops the ring from floating as designed, so use an inch pound torque wrench.
How long does a rear ring change take? With the rotor off the car it is a short bench job. The cap screws are removed, the worn ring comes off the hat, and the new ring is fitted with the supplied hardware. Most owners can complete both sides in an afternoon with hand tools.

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 390mm Rear Replacement Rings for 911 GT3, GT2 RS and Cayman GT4 RS [D2-154]

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GiroDisc Porsche 390mm Rear Replacement Rings for 911 GT3, GT2 RS and Cayman GT4 RS

Fitment and Installation

Features

What’s Included

Applications

Notes

Frequently Asked Questions

About GiroDisc

Reviews