i’ve been a triathlete for 25+ years
I’ve been a road-bike rider for only 4 years, and I have personally experienced the death wobble twice, the first time almost crashing at 40mph. A riding buddy did crash on a fast descent when his Trek 5500 started behaving like an overcooked noodle, and ended up in a coma for five days.
now, there are a variety of inputs that will cause speed wobble
Is that your concern? The excitation mechanisms that will precipitate a death wobble, not the fact that the frame has undamped resonances to begin with?
Who cares about the reason for the excitation? An appropriately sharp impulse can excite any resonant frequency on a frame that has not been properly designed.
most all bikes today on the road are properly built
It is my firm belief that none of the bikes today are properly designed: if Trek, the giant of the industry, produces frames that exhibit death wobbles, then I have absolutely no confidence that any other maker addresses these issues either. My belief is that the design methods employed in the auto and moto (and many others of course) industries have not transitioned to the bicycle industry yet – and your account of how your company designed and manufactured bikes confirms this.
I am therefore convinced that all bikes on the road today have this problem, and whether a certain rider will experience this phenomenon is simply pure luck.
my car will exhibit that same front end shimmy on occasion
And for the n-th time I am telling you that the shimmies, the headshakes, the tank-slaps, are all a fundamentally different phenomenon than a death wobble: they are manifestations of a damped resonance, whereas the death wobble is an undamped one. The major problem with undamped resonances is that the frame amplfies the external excitation, so for instance, if the external excitation has an amplitude of 1 inch, the frame will start shaking with a higher amplitude; even worse, when the frame starts shaking at resonance, it provides a positive feedback mechanism, i.e., the amplitude gets higher and higher until there is a structural failure (or, more commonly, the rider crashes) – that is, it is not the excitation that will kill you, it’s the frame that is trying to self-destruct.
John