Spec Aluminum Single Mass Flywheel SAC SB55A – 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 is SPEC's aircraft-quality billet aluminum single mass flywheel for the N55 cars, cut to the OE / self-ratcheting (SAC) clutch pattern. At 16 lb it removes the dual-mass damper and a large share 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
• Weight: 16 lb (SPEC published)
• 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: works with the stock clutch or any stock-design self-ratcheting (SAC) pressure plate. It is not an actual dual mass flywheel.
• Not for use with SPEC clutch kits whose part number ends in “-2”.

PARTS INCLUDED

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

TECH RESOURCES

Additional Parts Required

• None required. This flywheel runs with the stock clutch or a stock-design SAC aftermarket clutch. If you are replacing the clutch at the same time, use a SAC-pattern kit such as SPEC Stage 2+ SB553H.
• Do not pair this flywheel with SPEC clutch kits ending in “-2” — those take the SB55A-2.
• 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. 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

VEHICLE APPLICATIONS