Widely imitated, the safety bicycle completely replaced the high-wheeler in North America and Western Europe by 1890. Meanwhile, John Dunlop's reinvention of the pneumatic bicycle tire in 1888 had made for a much smoother ride on paved streets; the previous type were quite smooth-riding, when used on the dirt roads common at the time. As with the original velocipede, safety bicycles had been much less comfortable than high-wheelers precisely because of the smaller wheel size, and frames were often buttressed with complicated bicycle suspension spring assemblies. The pneumatic tire made all of these obsolete, and frame designers found a diamond pattern to be the strongest and most efficient design.