Which Mustangs can use the GiroDisc S550 Front Rotors?

The S550 Front Rotors fit the Mustang GT ordered with the optional Performance Package six-piston Brembo front calipers, along with all Bullitt and Mach 1 models. Cars on the standard front brakes are not covered by this part, so check the calipers before ordering.

How much lighter is the GiroDisc rotor than the stock Brembo disc?

GiroDisc quotes about 24.1 lb for its rotor against roughly 33.4 lb for the factory front rotor. That is around 9.3 lb less at each front corner, or more than 18 lb across the axle, all of it rotating and unsprung weight.

What size are these front rotors?

GiroDisc lists them at 380mm in diameter and 34mm thick, built as a direct replacement for the factory rotor used with the six-piston Brembo calipers. That is what lets them bolt on without spacers while leaving brake balance and ABS calibration unchanged.

Can the iron rings be replaced separately later?

Yes. When the iron wears to the minimum thickness marked on the hat and ring edge, GiroDisc D1-067 rings bolt to the existing hats with new hardware. The rings are sold in pairs, and the aluminum hats remain in service for the life of the car.

Why do floating rotors suit track use on an S550?

The iron ring can expand with heat independently of the aluminum hat, so it stays flat instead of distorting after repeated hard stops. Curved vanes pump air outward through the ring, which keeps temperatures under control during a long session.

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Description

GiroDisc S550 Front Rotors for Ford Mustang GT, Bullitt and Mach 1 with Brembo Brakes

GiroDisc’s S550 Front Rotors are a 380mm by 34mm two-piece design for the Ford Mustang GT with the optional Performance Package six-piston Brembo calipers, and for every Bullitt and Mach 1. GiroDisc weighs each rotor at about 24.1 lb against roughly 33.4 lb for the factory part, removing more than 9 lb from each front corner. Seventy-two internal curved vanes cool the ring, and the hat is machined from US-sourced 6061-T6 aluminum. For a Brembo-equipped S550 that sees track days, it is a direct and sensible front brake improvement.

Bolt-On and Go

The rotors bolt straight on in place of the original discs and the six-piston Brembo calipers go back on with no modifications. The factory diameter is retained, so brake bias and ABS efficiency stay as Ford set them. The S550 Front Rotors use alloy steel drive pins with anti-noise spring washers, which let the ring grow with heat and keep it quiet when cold.

Features

380mm by 34mm floating rotor for six-piston Brembo cars
About 9.3 lb lighter per corner than stock, by GiroDisc figures
72 internal curved vanes
US-sourced 6061-T6 aluminum hat
Grade 12 cap screws with hardened washers

What’s Included

Front rotor assemblies (L/R)

Applications

Ford Mustang Bullitt: S550 | 5.0L V8
Ford Mustang GT with Performance Package Brembo front brakes: S550 | 5.0L V8
Ford Mustang Mach 1: S550 | 5.0L V8

Notes

Mustangs without the six-piston Brembo front calipers are not covered
Worn rings are replaced with the GiroDisc S550 Brembo front replacement rings on the same hats
The GiroDisc S550 rear rotors complete the set
Stock photography may not depict the actual product

Frequently Asked Questions

Which Mustangs can use the GiroDisc S550 Front Rotors? The S550 Front Rotors fit the Mustang GT ordered with the optional Performance Package six-piston Brembo front calipers, along with all Bullitt and Mach 1 models. Cars on the standard front brakes are not covered by this part, so check the calipers before ordering.
How much lighter is the GiroDisc rotor than the stock Brembo disc? GiroDisc quotes about 24.1 lb for its rotor against roughly 33.4 lb for the factory front rotor. That is around 9.3 lb less at each front corner, or more than 18 lb across the axle, all of it rotating and unsprung weight.
What size are these front rotors? GiroDisc lists them at 380mm in diameter and 34mm thick, built as a direct replacement for the factory rotor used with the six-piston Brembo calipers. That is what lets them bolt on without spacers while leaving brake balance and ABS calibration unchanged.
Can the iron rings be replaced separately later? Yes. When the iron wears to the minimum thickness marked on the hat and ring edge, GiroDisc D1-067 rings bolt to the existing hats with new hardware. The rings are sold in pairs, and the aluminum hats remain in service for the life of the car.
Why do floating rotors suit track use on an S550? The iron ring can expand with heat independently of the aluminum hat, so it stays flat instead of distorting after repeated hard stops. Curved vanes pump air outward through the ring, which keeps temperatures under control during a long session.

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 S550 Front Rotors for Ford Mustang GT, Bullitt and Mach 1 with Brembo Brakes [A1-067]

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GiroDisc S550 Front Rotors for Ford Mustang GT, Bullitt and Mach 1 with Brembo Brakes

Bolt-On and Go

Features

What’s Included

Applications

Notes

Frequently Asked Questions

About GiroDisc

Reviews