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 deflection 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!
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.