ACT 2006 Subaru Impreza HD-M/Race Rigid 6 Pad Clutch Kit
ACT SB10-HDR6 is a dedicated race clutch for the Subaru WRX STI six-speed, listed here for the 2006 Impreza WRX STI. It pairs ACT's Heavy Duty pressure plate with a rigid, six-pad ceramic disc and the Monoloc release-bearing retainer. This is the kit for a time-attack, rallycross or drag STI where heat capacity and fast shifts matter more than street manners. ACT itself recommends it for race use only, so if the car is a daily driver, read the comparison further down before ordering.
ACT rates the kit at 668 ft-lb at the crank, 88 percent more than the factory clutch, on a 9.4 in (240 mm) ceramic disc with a 1 in input shaft. The key word is rigid. ACT's 6240018 disc has no damper springs in the hub, which makes it lighter, so the gearbox input spins down faster and shifts go in quicker. Without springs, though, every firing pulse and every hard engagement goes straight into the transmission. ACT spells out the result: harsher engagement, increased gear rattle, and a rigid design that may increase spline wear.
The pressure plate is ACT's SB019 Heavy Duty unit, which keeps pedal effort light to moderate compared with ACT's Xtreme plate. The M in HD-M is Monoloc, a one-piece hardened chrome-moly retainer that replaces the STI's two-piece wedge collar and wire ring on the pull-type release bearing and loads the bearing evenly against the plate.
Kit contents per ACT: SB019 pressure plate, 6240018 six-pad rigid race disc, RB601 release bearing, PB1004 pilot bearing and AT90 alignment tool. A flywheel is not included.
Rule out hydraulics first: air in the line, a weak slave cylinder or wrong pedal free play can all mimic a worn clutch. Then load-test it in fourth gear from low rpm; if the engine speed climbs faster than road speed as boost builds, the clutch is not holding. Our transmission slipping diagnosis guide covers the process, and shift flare vs. slip helps separate a clutch issue from a gearbox or engine-management issue.
Our listing is titled for the 2006 Subaru Impreza and applies to the 2006 WRX STI six-speed. ACT's application chart for SB10-HDR6 runs from the 2004-2014 Impreza WRX STI through the 2015-2021 WRX STI, plus the 2007-2009 Legacy GT spec.B and JDM STI models. It does not fit the five-speed WRX or a non-turbo Impreza. If the car has had a transmission swap, go by the gearbox in it and send us the year and VIN if you are unsure. More Subaru clutch parts are in our rebuild kits and clutch section.
If the car still sees regular street miles, the SB10-HDG6 sprung version has the same plate, torque rating and Monoloc, but its spring-centered disc damps torsional shock and is easier on the gearbox. Choose the rigid HDR6 when the car lives on trailers and race tires.
| Brand | ACT |
| Part number | SB10-HDR6 |
| Fits | ACT 2006 Subaru Impreza HD-M/Race Rigid 6 Pad Clutch Kit |
| Vehicle fitment | Subaru Impreza Hd-M/Race Rigid 6 (2006) |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Same SB019 Heavy Duty plate, 668 ft-lb rating and Monoloc. HDR6 uses a rigid 6-pad disc with no hub springs for quicker shifts; HDG6 uses a spring-centered 6-pad disc that damps vibration and is better for street use.
ACT recommends it for race use only. Expect harsh engagement, more gear rattle and possible extra spline wear. For a street-driven STI, the sprung HDG6 or an organic street kit is the better choice.
No. It includes the SB019 pressure plate, 6240018 disc, RB601 release bearing, PB1004 pilot bearing and AT90 alignment tool. Resurface the stock flywheel or use ACT's 600235 or 600240.
No. ACT lists SB10-HDR6 for the WRX STI six-speed, the 2007-2009 Legacy GT spec.B and JDM STI models only.
ACT describes the Heavy Duty plate as light to moderate pedal effort and says its Heavy Duty plates typically raise pedal effort 15 to 40 percent over stock, depending on the application.
