The Knucklehead refers to a motor engine that was used in Harley Davidson motorcycles. However, the name has proven to be very memorable, so much so that it isn’t uncommon for motorcycle enthusiasts to refer to such motorcycles by their engine names rather than their model designations. Here are 10 things that you may or may not have known about the Harley Davidson Knucklehead:
1. It Is a Retronym
Knucklehead isn’t the official name of the motorcycle engine that it refers to. Instead, it is a name created by motorcycle enthusiasts, which became so popular that it has overtaken its official counterpart.
2. Named Thus Because of the Rocker Covers
For those who are curious, the Knucklehead is named thus because of the rocker covers, which bore a remarkable resemblance to huge clenched fists. This remains one of the motorcycle engine’s most notable features, which is often used by motorcycle enthusiasts to figure out exactly what they are looking at.
3. Came Into Existence in Tumultuous Times
The Knucklehead came into existence in the mid 1930s, which were rather tumultuous times to say the least. After all, the effects of the Great Depression were still evident in countries situated all around the world. Moreover, the specter of war hovered over both Europe and Asia where the Nazis and the Japanese Empire were very much active.
4. Disrupted By the War
Unsurprisingly, the Second World War caused a serious disruption in the number of Knucklehead-engined motorcycles that were being made because most of the necessary materials had to be used for the war effort. To get an idea of the degree of the disruption, the number of such motorcycles being made dropped from more than 4,000 in 1940 to a mere 158 in 1943.
5. Knucklehead-Engined Motorcycles Broke Records
Knucklehead-engined motorcycles managed to become very popular very fast. In part, this momentum was fueled by how said motorcycles were used to break records as well as perform other impressive feats. For example, the rider Joe Petrali took such a motorcycle to Daytona where he proceeded to break a record by getting a combined average of 136.183 miles per hour. Likewise, another such motorcycle was used to break an endurance record by going 1,825 miles in no more than 24 hours.
6. Very Influential
The Knucklehead-engined motorcylces didn’t have the smoothest start. However, they proceeded to find plenty of success, so much so that they went on to influence not just subsequent Harley Davidson motorcycles but also a wide range of rides inspired by those subsequent Harley Davidson motorcycles as well.
7. Not Harley Davidson’s First OHV Engine
Knuckleheads were OHV engines, meaning overhead valve engines. However, they weren’t the first time that Harley Davidson had worked with OHV engines. For that matter, they weren’t even the second time, seeing as how the motorcycle manufacturer had already worked with them for a number of special projects.
8. First Production OHV Engine
With that said, there is a huge difference between something that is meant to see use in no more than a small number of special motorcycles and something that is supposed to be mass produced. As a result, the Knucklehead merits mention for being Harley Davidson’s first production OHV engine, thus making it something of a turning point in the motorcycle manufacturer’s long history.
9. Got Redesigned for Post-War Period
Like most long-lasting motorcycle engines, the Knucklehead saw its fair share of redesigns over time. In particular, it should be noted that it received a redesign for civilian use in the Post-War period, which was necessary because civilian use for the motorcycles meant very different conditions.
10. Replaced By the Panhead
In total, the Knucklehead lasted from 1936 to 1947. By 1948, the Knucklehead had been replaced by the Panhead, which picked up its name because its rockers bore a purported resemblance to cooking pans. In turn, the Panhead was replaced by the Shovelhead in 1965. These motorcycle engines plus the Knucklehead’s predecessor the Flathead were named thus because of the shape of their heads, which made it very easy for interested individuals to figure out what was what.