Which rotor uses the GiroDisc 408x36mm Front Replacement Rings?

GiroDisc names the GiroDisc 408x36mm Front Replacement Rings as the replacement part for its A1-291 front rotor on the Porsche 718 Cayman GT4 RS with factory iron brakes. They bolt to the anodized hats of that rotor and nothing else.

At what thickness are the GT4 RS rings worn out?

GiroDisc recommends replacement at 34mm. A new ring is 36mm thick, so there is 2mm of usable wear across the friction face. Replace the pair sooner if a crack leads to the edge of a ring, whatever the thickness. Measure at several points.

Do the 408x36mm rings fit cars with ceramic brakes?

No. The rings are designed for GiroDisc hats only, and the A1-291 rotor they belong to is listed for GT4 RS cars with the factory iron brake system. Cars with Porsche Ceramic Composite Brakes are not covered by either part.

Is hardware included with the GT4 RS front rings?

Yes. GiroDisc supplies replacement hardware with each pair, so the fasteners that hold the floating mount are renewed along with the iron. Only the black anodized aluminum hats carry over from the existing rotors to the new rings. Nothing else is needed for the job.

How many vanes are cast into the GT4 RS front ring?

Seventy-two curved vanes, matching the complete A1-291 rotor. They act as a centrifugal pump, pulling air in through the hub and driving it out through the disc, which helps keep the ring cool under repeated hard stops on a circuit.

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Description

GiroDisc 408x36mm Front Replacement Rings for 982 Porsche 718 Cayman GT4 RS

GiroDisc’s 408x36mm Front Replacement Rings for 982 Porsche 718 Cayman GT4 RS are the ring pair GiroDisc names for its A1-291 front rotor, renewing the iron while the black anodized hats stay on the car. Each ring is 408mm across and 36mm thick when new, machined from GiroDisc’s high-carbon iron casting with 72 curved vanes. Replacement hardware comes in the box. A GT4 RS that spends its weekends lapping will wear these down to 34mm in time, and this is the part that brings the front axle back.

Fitment and Installation

The 408x36mm Front Replacement Rings bolt only to GiroDisc hats; they do not fit factory rotors or other brands. With the rotors on the bench, unbolt the worn rings, fit the new pair with the supplied hardware and tighten the cap screws to no more than 60 in-lb (7 Nm). Left and right rings are handed because the vanes are directional.

Features

408mm diameter and 36mm thickness new
34mm minimum thickness
72 curved vanes per ring
For the hats of GiroDisc A1-291 front rotors
Replacement hardware included
Made in Bellingham, Washington

What’s Included

Front replacement rings (L/R)
Replacement mounting hardware

Applications

Porsche 718 Cayman GT4 RS: 982 | with GiroDisc A1-291 front rotors

Notes

These rings fit the hats of the GiroDisc GT4 RS front rotors only
The aluminum hats are not included
Cars with PCCB are not covered
Rear rings for the same car are the GiroDisc 992 GT3 and GT4 RS rear replacement rings
Stock photography may not depict the actual product

Frequently Asked Questions

Which rotor uses the GiroDisc 408x36mm Front Replacement Rings? GiroDisc names the GiroDisc 408x36mm Front Replacement Rings as the replacement part for its A1-291 front rotor on the Porsche 718 Cayman GT4 RS with factory iron brakes. They bolt to the anodized hats of that rotor and nothing else.
At what thickness are the GT4 RS rings worn out? GiroDisc recommends replacement at 34mm. A new ring is 36mm thick, so there is 2mm of usable wear across the friction face. Replace the pair sooner if a crack leads to the edge of a ring, whatever the thickness. Measure at several points.
Do the 408x36mm rings fit cars with ceramic brakes? No. The rings are designed for GiroDisc hats only, and the A1-291 rotor they belong to is listed for GT4 RS cars with the factory iron brake system. Cars with Porsche Ceramic Composite Brakes are not covered by either part.
Is hardware included with the GT4 RS front rings? Yes. GiroDisc supplies replacement hardware with each pair, so the fasteners that hold the floating mount are renewed along with the iron. Only the black anodized aluminum hats carry over from the existing rotors to the new rings. Nothing else is needed for the job.
How many vanes are cast into the GT4 RS front ring? Seventy-two curved vanes, matching the complete A1-291 rotor. They act as a centrifugal pump, pulling air in through the hub and driving it out through the disc, which helps keep the ring cool under repeated hard stops on a circuit.

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 408x36mm Front Replacement Rings for 982 Porsche 718 Cayman GT4 RS [D1-291]

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GiroDisc 408x36mm Front Replacement Rings for 982 Porsche 718 Cayman GT4 RS

Fitment and Installation

Features

What’s Included

Applications

Notes

Frequently Asked Questions

About GiroDisc

Reviews