Quad bikes – is the very term erroneous?

Essentially the English language does not have an adequate term for these vehicles as a three wheeled cycle was called a tricycle and therefore a four wheeled cycle should be called either a Quadcycle or a Quadrocycle.

Quatrocycle.

I have always called them simply "Quad" or "Quadcycle" - on rare occasions I have said (and heared) Quadricycle,

Quatrocycle.

That sounds like events relating to Suzi Quatro!