In conjunction with Shimano Hyperglide (HG) chains, the HG cassette sprockets enable fast and precise indexed shifting. The specially computer-designed sprockets feature specific tooth profiles and strategically positioned ramps that optimize chain guidance during shifting. Conventional sprockets allow the chain to first ride up on the tips of the teeth before settling onto the sprocket. HG sprockets guide the chain directly and immediately onto the next sprocket without any riding up. The result is quick, smooth, and silent gear changes.