Kyosho TRW159 3-Shoe Lightweight Flywheel DRX

This is Kyosho's lightweight flywheel for the DRX, built for the three-shoe clutch system and sold as an option part.

The flywheel bolts to the engine crankshaft and carries the clutch shoes on their pins. It has two jobs. It smooths the power delivery of a single cylinder engine, which fires only once every two revolutions and would otherwise deliver drive in pulses, and it provides the mounting and pivot points that let the shoes fly outward under centrifugal force to engage the clutch bell.

The lightweight designation changes how the engine behaves rather than just saving grams. Less rotating mass means the engine revs up and down more freely, which gives sharper throttle response and lets it recover faster after a corner. The trade-off is that a lighter flywheel stores less energy, so the engine is slightly more prone to bogging at very low rpm.

Note that the 3PC in Kyosho's naming refers to the three-shoe clutch type this flywheel is built for, not a pack quantity. Kyosho lists it as an option part for the DRX.