Spec Aluminum Single Mass Flywheel Non-SAC SB55A-2 – BMW 1M & N55 (E8x / E9x / F22 / F3x / F10)

OVERVIEW

SPEC billet flywheels are CNC manufactured on-site to a .001 in. tolerance, against an industry standard of .010 in. That precision gives perfect balance and a perfectly flat bedding surface for the clutch disc. All SPEC flywheels carry SFI certification.

The SB55A-2 is SPEC's aircraft-quality billet aluminum single mass flywheel for the N55 cars, cut for SPEC's non-ratcheting “-2” clutch kits. It removes the dual-mass damper and most of the rotating mass, so the engine picks up and settles faster between shifts. SPEC builds flywheels for specific driving environments and does not treat them as a one-fits-all lightweight part — consult SPEC or Speed Logic for a recommendation.

SPECS

• Type: single mass billet flywheel
• Material: aircraft-quality billet aluminum
• CNC machined to a .001 in. tolerance for a flat clutch bedding surface and true balance at rpm
• SFI certified
• Rebuildable, with a replaceable steel friction plate
• Clutch compatibility: for use with SPEC SB55x-2 / non-SAC clutch kits only. Will not work with the stock clutch or a SAC-pattern kit.

PARTS INCLUDED

• 1x SPEC billet aluminum single mass flywheel
• Pressure-plate-to-flywheel bolts

TECH RESOURCES

Additional Parts Required

• A matching SPEC non-SAC clutch kit is REQUIRED — a SPEC N55 kit with a part number ending “-2” (SB551-2, SB552-2, SB553H-2, SB553-2, SB553F-2, SB554-2 or SB555-2). Each of those kits is also offered with this flywheel as an option on its own listing.
• Pilot bearing, release bearing and alignment tool come with the SPEC clutch kit — they are not supplied with the flywheel.
• Installer-supplied: new flywheel-to-crank bolts (BMW specifies single-use bolts), a flywheel locking tool and a torque wrench.
• When switching to a single mass flywheel some flywheel chatter or rattle is to be expected; aluminum transmits more noise than steel and makes smooth low-speed starts harder.

Installation

• SPEC does not publish a downloadable installation PDF for this flywheel — follow the instructions supplied with the flywheel and clutch kit.
• Installation requires removal of the transmission and should be carried out by a qualified technician. Use new flywheel-to-crank bolts and torque to BMW specification.

Notes

• Steel version: SPEC SB55S-2. Confirm fitment with Speed Logic before ordering.
• 2011+ Z4 sDrive35i (N54) uses SPEC's N55-family clutch kit and SB55S-2 / SB55A-2 flywheel.

PART NUMBER

• SB55A-2

VEHICLE APPLICATIONS