Haha this is all so ridiculous, there are trucks getting used much harder then our 80's running full aluminum trailing arms and suspension links. Not to mention if you search aluminum arms have already been done for 80's. There was a gentleman who owned or worked for Taylor guitars that had custom aluminum arms cut.
forum.ih8mud.com
Thanks for finding that!
And I think it's important for some to realize that 7075 is some special stuff, different from your typical 6061 and A356 varieties- 7075 is not the stuff that wheels and engine parts are made from. 7075 is not going to fail as an 80 series radius arm. You'd rip the mounts off the frame or the axle before the arm failed.
And again, I have nothing against steel, but I make parts from various materials everyday. I'm familiar with a lot of different materials and mild steel isn't exciting to me. I would be excited to make radius arms from A514, but milling 1-3/4" T1 plate into radius arms would not be economical at all and fabricating from thinner sections and thinwall tubing around the bushings would be a ton of labor and welding the thin tubing in would negate the benefits of using a premium material. If they were machined from solid T1 plate one real slick thing you could do is gas nitride them and they would be an indestructible hard and bright silver because of the chromium content in T1 steel.
I've mentioned it a couple times in this thread, but the biggest draw to using aluminum for 80 arms to me is not the lightweight, but the fact it hardcoat anodizes well. Everybody's seen anodized aluminum, but type 3 is different stuff. Regular anodize is a fast process, it effects the first couple ten-thousandths of an inch. About the same as electroplating with zinc. It's primarily for looks. Form, not function. Type 3 hardcoat is a slow process done with refrigerated acid and high current electricity to build a thick, ultra hard layer on the surface.
Lets say you get some powdercoated arms. They look amazing out of the box. While putting them in you put a couple small chips in them, no big deal. A couple years go by and that powdercoat, as it is plastic, doesn't look new anymore. It's faded and there's some rust where it chipped. 5 years and they don't really clean up anymore when you powerwash the underside, the plastic is oxidized and dirt is embedded into the surface. They definitely don't look new anymore.
Lets say you had used hard anodized aluminum arms. You couldn't scratch or chip them when installing. Because hard ano is so slick nothing sticks to it. It's like a new teflon frying pan only it won't give you Alzheimer's- In fact there are high-end cooking pots and pans that are hard anodized aluminum because nothing sticks to it. So anyway, 2 years down the road, the arms wash right off and look like new, 10 years, 20 years, 50 years, doesn't matter because type 3 hardcoat doesn't degrade nor does it have any dyes to fade out like type 2 ano.
In no way do I think 7075 arms are a one size fits all solution for every application. Obviously, if you regularly weld on your radius arms 7075 would not work for you. I simply feel like 7075 is the right material to make radius arms out of if you owned a manufacturing business and wanted to make some economical arms to correct castor for a lift and add a bit of strength over stock.
But all I've done is a rough cad sketch to nest the arms to get a material size and quoted out the material from one supplier. I think I'm going to make two sets, one for me and one for a friend, see if there's something I'm missing. If they work well and the price can make them an economical choice maybe others will want them too.
