The 1958 Harley Davidson Duo-Glide is one bike that has come to be loved by many. Thanks to its power, rear suspension system, and ease of use, the Duo-Glide is rated among the best bikes of all times. Although most people celebrate and love the Duo-Glide, only a few know that it was not an original creation. The Duo-Glide was not designed from scratch as you would expect. It is just an improvement of previous Harley Davidson bikes starting as early as 1936.
Development Of The 1958 Harley Davidson Duo-Glide
In 1948, giant motorbike manufactures Harley-Davidson decided to revise their model F's 74ci twin engine. They changed the overhead valve and added new rocker covers that gave the bike a new look and name "Panhead". Although this was just a nickname, only a few people knew the official name of the Davidson F after remodeling.
The production of this series of OHV Harley's had started early in 1936. The OHV Harley's saw the introduction of 61ci in the "Knucklehead". This was the first time to have overhead valve engines used on Harley's roadster bikes. Previously the overhead valve engines were only used on singles and racing twins.
The knucklehead (Model E) became the pioneers of more important developments to follow in the line. The following models, especially EL brought an advanced level of performance to Harley Roadsters.
A few years down the line, Haley Davidson was already looking for ways to improve the performance again. The whole idea of staying at the helm of roadster motorbikes was taking over and the competition was getting tougher by the day. H-D opted to increase the engine capacity as it was the only way out. They managed to increase the capacity from 60ci to 74 ci in the FS and the Fl models. The new improved roadsters were unveiled in 1941 and they incorporated a number of features. Under the new nickname " Seventy Four" they had an engine that was enabled to cope with the new power at 48 bhp in the FL series.
In a nutshell, due to the quick ageing of the Model E( knucklehead), Harley-Davidson sought to revise the bike in 1948 and came up with the "Panhead. Although the engine and engineering fundamentals remained the same, the Pan head enjoyed new aluminium cylinder heads and unique rocker covers. The oil lines were embedded internally and new hydraulic valves adopted. These changes helped reduce the tappet noise and made it easy to repair the bike in case of a breakdown. The changes also saw the improvements in the bike power to 50 bhp in the 74ci model. These improvements made the Pan head a more reliable bike than the predecessor.
From The Pan head To The Duo-Glide
By 1948, the Pan head was the bike that was recognized at Harley's for the Roadster version. However, even the improvements made did not quench the thirst for a better version. The Pan head featured a new wishbone frame and down tubes that appeared to bend. In 1949, the bike gained an addition of the hydraulic damped front fork. Thanks to its latest addition, the bike was nicknamed the Hydra-Glide. This name only applied to the fork and never became an official name of the bike until the early 1950's. In 1958, Harley sought to make another improvement to the Hydra-Glide by adding Hydraulic damped rear suspension. This addition saw the name of the bike changed to the "Duo Glide". It is the same bike that was later enhanced by the addition of an electric starter to become the Electra-Glide. Since the first year of their production, the restored FLH Duo-Glide bikes were sold as new bikes. The introduction of genuine rear suspensions made it among the smoothest bikes on the road at that time. It is still among the most comfortable bike to ride today thanks to the rear suspension system. Many would argue that the introduction of a rear suspension system for the Duo-Glide is the most important improvement to the bike. Furthermore, after many decades of just relying on spring saddles, Harley opted for the swing arm with coil shocks in the year 1958. This made the bike among the best at the time taking over the market with a storm. The performance of this bike on the road made it riders favorite leading to its popularity in the 1950's.
Versions Of The Duo Glide
All through the development of the Harley roadster, the engine was developed in two versions. The low compression FL engine and the high compression version FLH. The low compression version was mild, quiet and ran in a cool manner. It was also easier to kick than the FLH which hopped up on startup. The FLH was better suited for around-town driving and needed advanced technique than the less cumbersome version. After all the improvements made to the Big Twin bikes to attain the Duo-Glide, the engine remained at the 1200ccs mark. They were both advertised at 53-55 bhp for the FL and 58-60 bhp for the FLH.
Although the bike received a major boost by the introduction of rear suspensions, the seat post remained the same. Thanks to the improved suspension, the seat could now hold up to 600 pounds without a problem. The glide was later developed to give birth to the Electra Glide which shared most of the Duo-Glide features.
The 1958 Harley Davidson Duo-Glide is one of the smoothest bikes you could ride on the road. Thanks to its rear suspensions, the bike offers riders peace and quiet— even when riding through rough terrain. However, the Duo-Glide was not always as smooth as it is today. In fact, the bike is as a result of a series of improvements on the Harley Davidson Big Twin. Harley started the development of the Big Twin roadster in 1936. The bike was among the most powerful and enjoyed success on the road for several years. By the 1940's, Harley sought to improve it and came up with the Pan head. It is the Pan head was later improved to give birth to the much loved Harley Davidson Duo Glide.
Written by Benjamin Smith
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