Originally Posted by tileman
In a crash situation I'd think HDPE/Delrin etc would result in a better outcome for the rider?
The Delrin I've used can crack and break, resulting in sharp edges. That could be worse than aluminum, especially on the nav tower. HDPE won't do that, unless it sits in direct sunlight for 5 or 10 years.
I like the idea of the flexibility of HDPE in this application. It will flex a bit or a lot in a crash, and bounce right back, or nearly right back. To me, that's the value of using HDPE here. Aluminum will bend, maybe a lot, resulting in a permanently twisted nav setup.
My concern with HDPE in this application would be where are all fasteners are. Without super wide washers everywhere, the holes and the material around the holes may well mush out, allowing everything to loosen up.
I used a LOT of HDPE on my Dakar bike (probably 15 pounds of it), though not on the nav tower. In the right places, it works very well, even in some high stress locations. One location gets a 200+ pound load on it occasionally, and it's been rock solid.