ACT 06-25 Subaru WRX (Excl. STI) Heavy Duty Performance Street Sprung Clutch Kit
If your WRX, Legacy GT, Outback XT or Forester XT has started slipping in the upper gears after a tune, or the original clutch is simply worn out and you want a little more holding power without a race-car pedal, the ACT SB12-HDSS is the mildest kit in ACT's SB12 family. It pairs ACT's Heavy Duty pressure plate with a full-face organic street disc and a lightweight Prolite flywheel, and it is built for daily-driven turbo Subarus, not the STI.
The factory clutch on these cars is a 230 mm unit. The SB12 kits step that up to 240 mm, which is why the kit ships with ACT's own flywheel: the bigger disc will not work on the stock flywheel. In SB12-HDSS that flywheel is the XACT Prolite 600895, the lighter of ACT's two flywheel styles for this platform, so the engine revs more freely between shifts. The complete kit weighs 24.3 lb according to ACT.
ACT rates the combination at 449 ft-lb at the crank, 46 percent over the factory clutch. The SB020 Heavy Duty plate uses ACT's diaphragm design to raise clamp load and reduce deflection, while the 3000505 Performance Street disc uses an organic lining with high copper content and a sprung hub. ACT describes the feel as light to moderate pedal effort with smooth, positive engagement and OE to mild gear rattle. If you need more capacity, the SB12-XTSS Xtreme street kit keeps an organic disc with a stiffer plate, and the SB12-HDG6 race kit swaps in a 6-pad ceramic disc.
Do a high-gear roll-on: fourth gear at about 2,500 rpm, then full throttle. If the tach climbs faster than road speed, the disc is slipping. Before pulling the transmission, make sure the pedal returns fully and the hydraulic system is not holding the clutch partly released, and look under the bellhousing for oil from the rear main seal. Our slipping diagnosis guide walks through the checks, and the WRX clutch replacement cost guide covers labor by generation.
ACT's vehicle selector for SB12-HDSS covers the Impreza WRX (including Premium, Limited and TR trims), the 2015-up WRX in Base, Premium, Limited, Sport and Sport-tech trims, the Legacy GT and spec.B, Legacy 2.5GT, Outback XT, Forester XT and the Baja Turbo. The listing covers 2006-2025 WRX and excludes the US WRX STI, which uses a different six-speed and clutch. Because these cars changed engines and gearboxes over the years, and many have had transmission swaps, send us your year and VIN if anything is not original, especially on a 2018 or later car. Browse other Subaru clutch parts in our rebuild kits and clutch section.
| Brand | ACT |
| Part number | SB12-HDSS |
| Fits | ACT 06-25 Subaru WRX (Excl. STI) Heavy Duty Performance Street Sprung Clutch Kit |
| Vehicle fitment | Subaru Wrx (2006-2025) |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
No. This kit is for the WRX, Legacy GT, Outback XT, Forester XT and Baja Turbo. The US STI uses a different six-speed and needs a different clutch.
The SB12 kits convert the factory 230 mm clutch to 240 mm, so ACT supplies its XACT Prolite flywheel 600895 to match the larger disc.
ACT rates SB12-HDSS at 449 ft-lb of torque at the crank, 46 percent over the factory clutch.
Both use the SB020 Heavy Duty plate and the 3000505 organic disc with the same 449 ft-lb rating. SB12 kits come with the lighter Prolite flywheel; SB11 kits use the heavier Streetlite flywheel for a smoother, more stock-like feel.
ACT describes the Heavy Duty street kit as light to moderate pedal effort, the lightest of its SB12 options.
The kit already includes the pilot bearing, release bearing and alignment tool. Replace a leaking rear main seal, a worn fork or pivot, and the clutch fluid while the transmission is out.
