Why are Knuckleheads REALLY called knuckleheads?

Now I don't mean to start any fights, and this could get hot, but not everyone buys into the "rocker box looks like yer knuckles" theory. I have another theory, or explanation.

Can anyone guess, or does anyone know????

Urban legend incarnate? I mean flatheads, yes, pan heads, yes; blockheads because magazines needed to invent a name and that was th best they could come up with. Evos, obviously. But knuckleheads and shovel heads, I never dud really know.

It's more of a technical answer, and has nothing to do with anything looking like a human fist. (why don't we call them "fist-heads"?)

I thought they were named after the people who rode them.

In my case that would be true...but I've switched to a flathead. They did call me "Knucklehead Ken", back in the day also, when I rode a knuck...but maybe riding the knuck had nothing to do with it. !!

Not a lot of guesses, I'll give it one more day.

k.

For what is worth Harley-Davidson never called it a Knucklehead. It was referred to as the OHV.

It might be more use asking when the term was first used, who by, and in what context?

Naw...here's the deal. I was looking through a 1920's book once, it wasn't a Harley book, I don't remember what it was, but it had some exploded views of machinery with nuts and bolts. There was one diagram with a bolt threaded on both ends, blank in the middle, with blind or acorn typed nuts on both ends.

This was labeled as a "knuckle bolt". It was not part of a car's front end.

If you think about it, that's exactly what a knucklehead's rocker arm shaft is. So I've always wondered if the knucklehead was so named because at the time, the rocker shaft would have been considered a "knuckle bolt", and the "knuckle bolts" were in the head, but then that terminology for that kind of bolt faded away.

??? Just food for thougt, and just a theory on my part, as the "rocker box looks like yer knuckles" theory has never rung true for me. ?? And I've never found that reference to that type of bold again...but I've never gone searching through 1920's-early '30's tech manuals either.

krazy ken.

Looking around a little, the term still seems to be used in respect of the front suspension arms on cars. The double threaded end don't seem to be relevant, my reading of it is that they are the pivots fir a "knuckle joint", a joint with a limited articulation in a single plane of movement. This would be a correct description of the rocker arm pivots and would differentiate the knucklehead style of construction from the earlier pivots on the ice ( f-head or pocket-valve) engines.

JAP engines changed over to a similar style of construction around that time; the earlier ones had rocker pivots passing through exposed pedestals and were known subsequently, although not at the time, as "dog-ear" engines because they did look very like a dog's ears and this type of mount was so called, at least in British engineering terminology


I'd be more interested to know when the term first appeared.

Looking about, Rick Schunk makes the assertion in his book about Big Twins that it was simp,y known as the OHV, EL or FL until the panhead appeared. This would make sense in that the MoCo used the same designation for successive models. I would also suspect that the term "panhead" was invented by the custom bike magazines, because I have a couple of volumes of Cycle World road tests including an early Electra Glide, which clearly describes the changeover to the Shovelhead style heads but does not use either term, implying that touring riders of the time used the factory model designations.

Actually, that would work quite well because at that time ( late 1960s ) a knucklehead would be a bike with rigid frame and springer forks, a Hydra-Glide would be a rigid, tele-fork panhead, a Duo-Glide a spring-frame likewise and an Electra Glide, an electric-start Shovelhead.

Anyone?

Yes, when the term came into use would have a lot to do with it. Sure would be nice to have the time to really research it. Or not. But those are all good points. Just thought I'd throw that out, because, again, I've never really bought into the common/popular explanation.