Harley-Davidson has made touring motorcycles under the FLH name since 1949.
The Harley-Davidson FLH model has had three major incarnations, the Hydra-Glide, Duo-Glide and Electra-Glide. Harley-Davidson identifies its motorcycles with a specific model name and each belongs to one of five model families; Sportser, Dyna, Softail, VRSC (V-twin, racing, street, custom), and Touring. Harley also manufactures trikes and offers custom models of various bikes under the CVO (Custom Vehicle Operations) banner. Each model also has a multi-letter designation. Generally, the first (and sometimes second) letter designates the engine type and sometimes the frame or front end, as in the FL model, introduced in 1941.
In 1949, Harley added its first hydraulic front forks to the FL model and dubbed it the FLH or Hydra-Glide. The Hydra-Glide maintained the big V-twin engine that Harley had introduced in 1948, the Panhead, which replaced the Knucklehead. The 1949 Hydra-Glide engine was 1,200 cc with a 7-to-1 compression ratio and reportedly put out 50 horsepower at 4,800 rpm and gave the bike a top speed of 100 mph. Until 1952, the FLH Hydra-Glide was equipped with a foot clutch and hand shifter. Refinements to the Panhead engine in 1953 increased compression to 8-to-1, horsepower to 60 at 4,800 rpm and top speed to 105 mph. Elvis Presley owned a 1957 FLH, the last year that the model was called the Hydra-Glide.
The next big change to the Harley-Davidson FLH was the addition of rear brakes and hydraulic rear suspension, in 1958. Harley renamed the new model the Duo-Glide, though it maintained the FLH model designation. The Duo-Glide also featured a sprung seat, making it even more comfortable, and suitable for touring. The rear suspension on the Duo-Glide had three adjustment settings: solo, heavy, and tandem.
In 1965, Harley-Davidson replaced the kick starter on the FLH with an electric starter and renamed the model the Electra-Glide, again keeping the FLH identifier. The electric starter necessitated a larger, 12-volt battery and modifications to the frame to accommodate the bigger battery. The 1965 FLH had a compression ratio of 8-to-1, 60 horsepower at 5,400 rpm and a top speed of 100 mph. To increase the range of the big-twin tourer, the Electra-Glide also had a 5-gallon “Turnpike” fuel tank. CNBC names the 1965 Electra-Glide as one of the most notable Harleys ever, and puts the estimated value of one of the approximately 6,900 original models at $30,000, as of 2011. Harley-Davidson replaced the Panhead engine with the Shovelhead on all Electra-Glide models beginning in 1966.
Harley-Davidson continues to manufacture variations of the Electra-Glide. In 1969, Harley added the iconic fork-mounted “batwing” fairing. The FLH got a power increase in 1978 when the Shovelhead was bumped up to 1300 cc. The FLHR Road King burst onto the scene in 1994. Still technically considered an Electra-Glide, the Road King has spawned a number of variations of its own. For the 2011 model year, Harley-Davidson listed six distinct FLH model variations on its website; the Electra-Glide Classic, Ultra Classic Electra-Glide, Electra-Glide Ultra Limited, Road King, Road King Classic, and the Street Glide.