Thanks for the links. Interesting videos. Which AL alloy is not described in either one and doing a quick search did not reveal which is the preferable alloy.

I would be surprised if any were age hardening alloys, which would have to be specified as not all AL age hardens as described. Age hardening is related to temperature (heat) which impacts the crystalline structure to change (as does the work hardening).

I wasn't being critical or expressing a bias, just wondering about the material properties and the production process along with the engineering considerations of both.
[MENTION=209177]3alarmer[/MENTION] - I am sorry you experienced significant injuries as a result of a failed bar. I understand the long term impacts from accidents. If replacing old bars with new ones gives you the confidence to continue to ride, that is great! Enjoy the ride!
My worst accident left me with a permanent vision impairment causing me to see double, depending on the range of focus. It is a challenge to wake up every morning and get my brain to switch dominate eyes! The nerves in my left forearm are still growing back after 11 years with new sensations occurring over long periods of time. Leaning the wrong way on my left arm is painful when the skin is pinched between the plate on the bone and whatever I am leaning on. Accidents and age change your perspective and sometimes makes you more aware of a given situation.