hi, thanks for answer.
I am not as concerned about the crashes or constant static loads, as in my case I need a tower for travelling purposes.
I've seen in some ride reports people having troubles with their custom towers fatigue, from being bashed for thousands of km.
In this case I think harmonic oscillations plays the the greatest role in fatigue, as aluminium have finite life.
What about the thin walled steel tubes, as used in oem bikes, to hold all the instruments
have anyone tried using steel? more labour intensive for sure