2004-2021 Subaru STI
2007-2009 Subaru Legacy GT Spec B
Note: Replacement for ACT SB4 part numbers
Wore out your ACT Performance Street Sprung Replacement Disc for the Subaru STI (3000503) and don't want to spend all the cash on a new clutch kit? Get this replacement instead!
ACT street performance spring replacement disc features premium organic materials with high copper content for better heat transfer. Performance street discs allow for quicker shifting and smooth engagement. These discs feature a reduced marcel for faster shift action to complement ACT pressure plates. ACT spring-centered assemblies use bushings and cone springs similar to factory clutch discs. This creates frictional dampening, which improves clutch life and reduces noise. Quiet operation with increased strength and reliability.
Feel - Smooth engagement, quicker shifts, OE to mild gear rattle
Recommended Use - Recommended for street and race use
ACT Difference - Steel-backed linings for higher burst strength, reduced marcel for quicker shifts
Manufacturer Warranty - Limited Retail Warranty
Installation Instructions - ACT's General Installation Instructions
Can an ACT Race puck-style disc be used for daily driving, and is it recommended?
ACT's race discs are very aggressive and provide no-nonsense performance response. As a result, the engagement is harsh. Taking off from a stop can cause judder and/or an uncomfortable noise. These characteristics have no effect on the performance on the clutch or the drive line components. This type of disc should only be used in a professional race setting and never on the street. ACT always recommends using an organic disc on the street because it offers a smoother engagement and a longer lasting performance value for everyday drivers.
When should a clutch disc be replaced?
The majority of new discs measure .312-.315” (7.93 – 8.00mm) thick – fully worn is .275” (7.00mm) or below. A few applications (mostly Audi and BMW) start out at .332 - .335” (8.43 – 8.50mm). These are to be replaced when below .295” (7.50mm). It’s best to measure with a micrometer. Puck discs are measured as-is, where organic street discs are correctly measured by fully compressing the engagement cushion (marcel) between the linings. If the lining rivets on either side of the disc have made contact with the flywheel or pressure plate face, the disc must be replaced. Note: Using a disc that is thicker or thinner than the working range the pressure plate is designed for will have varying, and often very poor, results.