Although the M151 mostly retained the same basic layout and dimensions of its predecessors, it was for all intents and purposes a completely new design. Unlike previous jeep designs, whose structure consisted of a steel tub bolted onto a separate steel frame, the M151 utilized an integrated frame design, which integrated the box frame rails and the sheet-steel body into a unibody structure. Eliminating the separate frame gave the M151 slightly more ground clearance, while at the same time lowering the center of gravity. Although the vehicle's dimensions were only slightly enlarged — the 85 inch wheelbase was 4 inches longer than its predecessor, or 5 inches compared to the Willys MB, and the width was increased 3 inches — combined with the improved space efficiency of the integrated body design, the vehicle was a bit roomier than previous jeeps, while retaining the same light weight.