Which PFC parts do the GiroDisc Rear Rings for Factory Hats replace?

The GiroDisc Rear Rings for Factory Hats are direct replacements for PFC part numbers 380.30.0047.451 on the left and 380.30.0047.461 on the right. They suit the 991 GT3 Cup and all GT4 Clubsport factory race cars running the Porsche/PFC hats and their original retaining ring hardware, with nothing extra to buy.

Why does a higher vane count matter on a race ring?

GiroDisc machines these rings from a 72-vane casting, where the original rings use 48 vanes. GiroDisc describes the higher count as an upgrade in durability and longevity, which matters to teams that cycle through rings across a long race season.

Is hardware included with the 991 Cup rear rings?

No. The rings are sold per pair without hardware. They share the factory tooth-drive configuration, so they plug and play with the existing Porsche/PFC hats and retaining ring hardware, and no additional hardware needs to be purchased for the swap.

What if my GT4 Clubsport runs GiroDisc hats?

Then these are not the correct rings. They are designed only for the factory Porsche/PFC hats. Cars fitted with GiroDisc hats need GiroDisc part number D2-238, the rear replacement rings made for the GiroDisc 991 Cup and GT4 Clubsport hats.

What are the new and minimum thicknesses of these rear rings?

Each ring is 30mm thick new on a 380mm diameter, and GiroDisc lists a 28mm minimum thickness. Replace the pair when the rings reach that figure or if a crack runs to the edge, and bed in the new rings before race pace on the next outing.

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Description

GiroDisc Rear Rings for Factory Hats on 991 Porsche 911 GT3 Cup and Cayman GT4 Clubsport

GiroDisc’s Rear Rings for Factory Hats are direct replacement rear rings for the 991 Porsche 911 GT3 Cup and every Cayman GT4 Clubsport factory race car, built to run on the Porsche/PFC factory hats and retaining ring hardware. They replace PFC part numbers 380.30.0047.451 left and 380.30.0047.461 right. GiroDisc machines them from a 72-vane casting, against 48 vanes in the original rings, for better durability and longevity. Teams already invested in factory hats can fit them without buying any additional hardware.

Fitment and Installation

The rings share the factory tooth-drive configuration, so they plug and play with the existing Porsche/PFC hats and retaining hardware. Each ring measures 380mm by 30mm new, with a 28mm minimum thickness. Cars running GiroDisc hats need different rings, GiroDisc part number D2-238, because these are made only for the factory hats. Bed the new rings in before full race pace.

Features

Direct replacement for PFC 380.30.0047.451 (left) and 380.30.0047.461 (right)
72-vane casting, against 48 vanes in the factory rings
380mm diameter, 30mm thick new
28mm minimum thickness
Same tooth-drive configuration as the factory hats
Reuses the factory retaining ring hardware

What’s Included

Rear replacement rings (L/R)

Applications

Porsche 911 GT3 Cup: 991 | factory race car
Porsche Cayman GT4 Clubsport: all factory race cars

Notes

The Rear Rings for Factory Hats fit Porsche/PFC factory hats only; hats and hardware are not included
Cars with GiroDisc hats need the GiroDisc 991 Cup and GT4 Clubsport rear replacement rings instead
Front rings for factory hats on the same cars are the GiroDisc front rings for factory hats
Stock photography may not depict the actual product

Frequently Asked Questions

Which PFC parts do the GiroDisc Rear Rings for Factory Hats replace? The GiroDisc Rear Rings for Factory Hats are direct replacements for PFC part numbers 380.30.0047.451 on the left and 380.30.0047.461 on the right. They suit the 991 GT3 Cup and all GT4 Clubsport factory race cars running the Porsche/PFC hats and their original retaining ring hardware, with nothing extra to buy.
Why does a higher vane count matter on a race ring? GiroDisc machines these rings from a 72-vane casting, where the original rings use 48 vanes. GiroDisc describes the higher count as an upgrade in durability and longevity, which matters to teams that cycle through rings across a long race season.
Is hardware included with the 991 Cup rear rings? No. The rings are sold per pair without hardware. They share the factory tooth-drive configuration, so they plug and play with the existing Porsche/PFC hats and retaining ring hardware, and no additional hardware needs to be purchased for the swap.
What if my GT4 Clubsport runs GiroDisc hats? Then these are not the correct rings. They are designed only for the factory Porsche/PFC hats. Cars fitted with GiroDisc hats need GiroDisc part number D2-238, the rear replacement rings made for the GiroDisc 991 Cup and GT4 Clubsport hats.
What are the new and minimum thicknesses of these rear rings? Each ring is 30mm thick new on a 380mm diameter, and GiroDisc lists a 28mm minimum thickness. Replace the pair when the rings reach that figure or if a crack runs to the edge, and bed in the new rings before race pace on the next outing.

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 Rear Rings for Factory Hats on 991 Porsche 911 GT3 Cup and Cayman GT4 Clubsport [D2-370]

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GiroDisc Rear Rings for Factory Hats on 991 Porsche 911 GT3 Cup and Cayman GT4 Clubsport

Fitment and Installation

Features

What’s Included

Applications

Notes

Frequently Asked Questions

About GiroDisc

Reviews