It wears huge, knobby tires, but it’s comfortable on the highway. We spent a few days behind with the three-motor version of the Hummer EV SUV to see if we could make sense of the bulky brute.

The SUV is propped on 18-inch beadlock wheels made by Dick Cepek that have been shod in Toyo Open Country M/T tires, backed by extra-large, 12-inch brake rotors. The interior of the Hummer has ...