Heat-treated 4140 material is harder and 114% stronger than stock
• Harder material, no thrust washers required – Where stock flywheels have thrust washers,
S&S flywheels have steel gripping the crankpin
• Larger 1.671" diameter crankpin - increased contact area and tighter press fit or a stronger
joint. No welding required!
• Integral mainshafts - eliminates two potential points of weakness
• Consistent balance and precision machining – Truer flywheels and less vibration
• Reduced mainshaft defle tion at high rpm – less vibration, reduced piston and rod side
thrusting, prevents oil pump damage, fully compatible with gear drive cams
• Capable of higher rpm – More available power!
All S&S flywheel assemblies for 1999-'06 engines have connecting rods with 7.667” length and full width straight wrist pin ends.
Flywheel assemblies supplied with sprocket shaft bearing race installed are compatible with stock roller style sprocket shaft bearings. Assemblies with no race require a Timken® sprocket shaft bearing.
Engines with strokes over 4" may require S&S® piston oiling jets (p/n 31-2026) and piston to jet clearance notches in the piston skirt to avoid contact.
Main Bearing Note: Most S&S flywheel assemblies for 1999-'16 big twin engines are designed for use with Timken® sprocket shaft bearings. They will fit directly in stock 1999-’02 Harley-Davidson® crankcases and in all S&S crankcases for 1999-'15 big twin engines, with no modifications. However, stock 2003 and later engines use a roller type bearing for the sprocket shaft. S&S does offer flywheel assemblies that are compatible with late roller style stock sprocket shaft bearings, but they are not recommended for very large, high performance engines.
S&S strongly recommends retrofitting 2003-'16 model crankcases to accept a Timken sprocket shaft bearing. A Timken conversion sleeve such as Screamin' Eagle® #34822-08 or Jim's® #956 may be used. A charging system spacer for 1999-'02 model year is also required.
If you choose not to convert your crankcases to a Timken sprocket shaft bearing, S&S flywheels may be used in 2003 and later engines by either purchasing the stock compatible flywheels or by installing Harley-Davidson® bearing kit #24004-03B when using S&S flywheels designed for Timken bearings. This bearing kit adapts the S&S sprocket shaft so it is compatible with stock roller type bearings. Verify that the bearing kit contains the 24604-00D or 24607-07 sprocket shaft bearing. Do not use a 24604-00, 24604-00A, 24604-00B or 24604-00C bearing. Please be advised that if this type of bearing is used, sprocket shaft bearing failure WILL NOT be covered under warranty.