Spec 07-1/09 BMW 335 3.0L Steel Flywheel (8-Bolt)
The SPEC SB53S-2 is a billet steel flywheel for the early twin-turbo N54 BMWs with a six-speed manual: the E8x 135i, E9x 335i and E60 535i built through January 2009, plus the N54 Z4 35i from the same production window. Most buyers are here for one of two reasons. Either the factory dual-mass flywheel has started to knock at idle and shudder on takeoff, or they are installing a SPEC non-ratcheting -2 clutch kit, and SPEC requires one of its own billet flywheels behind those kits. This one ships the same business day from the USA.
BMW built these cars with a two-piece dual-mass flywheel. Springs between the two halves absorb crankshaft pulses, and that works well until the springs and stops wear. On a tuned N54 the extra torque speeds that wear up, and the worn flywheel then lets the driveline slap back and forth. The SB53S-2 is a single piece of machined steel, so there is no spring pack to fail, and it gives the SPEC disc a flat, solid friction face to clamp against.
SPEC lists the SB53S-2 at 24 lb. That is the main reason to pick steel over SPEC's 16 lb SB53A-2 aluminum flywheel. The extra mass makes pulling away from a stop and crawling in traffic easier, keeps the idle steadier, and soaks up heat better during repeated launches. The aluminum wheel revs faster but is less forgiving in daily driving. Either way, a one-piece flywheel passes more gear rattle into the cabin than a healthy dual-mass unit. That is normal for the conversion.
Start with the car idling in neutral and listen. Press the clutch pedal; if the knock stops or changes pitch, the flywheel is the prime suspect. For slip, do a load test in fourth gear from about 2,500 rpm at full throttle and watch whether the tach climbs faster than road speed. Our slipping diagnosis guide walks through that test and how to rule out hydraulic problems first. With the gearbox out, a dual-mass flywheel whose two halves rock or turn more than a little against each other is worn.
SPEC divides the N54 cars by build date, not by model year. It lists the SB53S-2 for:
A 2009 car can go either way, so read the production month on the driver door jamb sticker. Cars built from February 2009, and the 2011-2013 335is, take the SB53S-3 steel flywheel instead. Our listing title calls this the 8-bolt version; count the flywheel bolts on your crank when the old flywheel comes off if you want a second check. This flywheel is meant only for SPEC's non-ratcheting -2 clutch kits, not the factory self-adjusting clutch. If you are unsure which version your car needs, send us the VIN before ordering. You can see more N54 clutch parts in our hard parts section.
| Brand | SPEC |
| Part number | SB53S-2 |
| Fits | Spec 07-1/09 BMW 335 3.0L Steel Flywheel (8-Bolt) |
| Type | Flywheels |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Only if it was built in January 2009 or earlier. SPEC lists cars from February 2009 production for the SB53S-3. Check the build month on the door jamb sticker or send us your VIN.
SPEC lists the steel SB53S-2 at 24 lb and the aluminum SB53A-2 at 16 lb. The steel wheel is easier to drive in traffic and holds heat better; the aluminum one revs faster.
No. SPEC lists it for its non-ratcheting -2 clutch kits only, such as the SB531-2, SB532-2 and SB533F-2. The factory self-adjusting clutch is not meant for it.
Expect more gear rattle at idle and a little more driveline vibration than a healthy dual-mass flywheel. That is normal for any one-piece flywheel.
The matching SPEC -2 clutch kit, new flywheel bolts, and the rear main seal if it shows any seepage. Bleed the clutch hydraulics with fresh fluid when you are done.
