A stump grinding wheel assembly having a disk-like wheel body. A plurality of bilateral mounting stations integral with the wheel body and arranged into spiral cluster groups. Each spiral cluster having an inner mounting station and at least one middle mounting station and an outer mounting station. The inner mounting stations are thicker than the middle mounting stations, which are thicker than the outer mounting stations. A pair of opposing side-cutters are disposed on each left and right side of the mounting stations. A separate plunge-cutter may be included with each spiral cluster. The bilateral mounting stations produce conically-helical cutting paths using identical side-cutters. The unequal width of the inner and middle and outer mounting stations enables better management of cutting forces in side cutting mode, which produces smoother operation.