Powerbond VT-VF 25% Underdrive Balancer Kit

25% Underdriven Balancer Kit

A 25% underdriven harmonic balancer, also known as a “crank pulley,” is intended to reduce harmonic vibrations in an LS engine’s crankshaft. The percentage denotes the pulley’s size in relation to the factory pulley. As a result, a 25% undriven harmonic balancer has a 25% smaller diameter than a factory pulley.The primary benefit of using a smaller harmonic balancer is that it reduces the crankshaft’s rotating mass, which can improve engine performance. Reducing the crankshaft’s rotating mass allows the engine to rev faster and respond to throttle inputs more quickly, leading to improved acceleration and overall performance.