Changes brought challenges. As the engine warmed, the new alloy cylinder heads expanded and grew much more than the old cast-iron heads; and because of the Big Twin’s nearly four-inch stroke, the amount of expansion was considerable. As the head grew away from the cylinder base, increased valve lash would have resulted, were it not for the incorporation of hydraulic tappets that automatically maintained valve clearances. Though these tappets initially were problematic until 1953—when their location was changed from atop the pushrods, where they were starved of oil, to the bottom, where they got ample lubrication—they meant that valve adjustment was forever crossed off the H-D rider’s list of frequent maintenance chores. Just one year later, in 1949, a hydraulically damped telescopic fork replaced the venerable springer front end, and the FL was aptly given the Hydra-Glide name. The mile-eating qualities of the Panhead became obvious when Harley-Davidson started its Mileage Club in 1951; within just four years, 73 riders had earned their 100,000-mile pins, many on Panheads. The Panhead grew even more comfortable yet when the 1958 Duo Glide introduced rear suspension. That year also was the last in which hand-shift/foot-clutch was available, and even then, it only could be had as an option.