Rear wheel skirts
 

I'm considering making some rear wheel skirts and I was wondering if this sheet metal would be strong enough:

24 in. x 36 in. Galvanized Steel Flat Sheet-GFS24X361P at The Home Depot

I was also wondering if it would be save to use the screws already in the wheel well by using a design similar to how weather spotter did his.
(File:GEDC0138.jpg - EcoModder)

Anyone have any comments?

I would say the sheet would be strong enough for sure, the screws in your fender wells will probably work, but I wouldn't try it on smaller cars, like my CRX. The screws just don't have enough threads to hold it.

They only give you two of the three dimensions. Off the top of my head, auto body sheet metal is 18 to 20 gauge. I think, like wire gauges, small numbers are thicker. If the edge is rolled around a wire or rod, like a Model A fender, you could use a thinner gauge. At least fold the edge to double the thickness.

That picture shows how Weather Spotter bent the metal, but I haven't seen how they are mounted. A permanently mount may lead to disappointment alongside a dark road on a rainy night.

You definitely want a easy/quick release/lock system. Since you have a pickup truck, you don't want to attach the skirts to the cab portion or the flex will start popping things. :(

As I progress in my aerodynamic trials, I've found that I have to build a separate support system fer my rear wheel skirts apart from my side skirts which are attached to the main frame. I'm looking to morph the wheel skirts into my rear wheel strakes, too... :D