Aluminum Vs Steel Skid Plates: How To Choose Which Is Best For Your Needs

• Cars

So you have noticed your car's underbelly scrapes the ground much more often than it should because you spend a lot of time off-road, and you've decided it's time to give your undercarriage some armor. You head to the market to find there are two different metals you can bolt up: aluminum and steel. Deciding between the two can be confusing, especially since neither wins outright. Things actually have more to do with how you drive your vehicle.

If you mostly daily drive and head off-road only occasionally, then aluminum makes more sense. It does not rust like steel and is also very resistant to corrosion. It also shrugs off the effects of road salt on your car. So it makes even more sense for someone who lives somewhere with coastal dampness and heavily salted winter roads. It's also significantly lighter, which can help you save fuel in the long run. Trail4Runner points out that every extra 100 pounds or so can trim your mileage by 1 to 2 percent. Over a year of commuting, that eats into what counts as good gas mileage.

On the other hand, if your weekends involve technical rock crawling, or if you regularly drag your undercarriage over ledges and boulders, steel is the better option. It simply soaks up repeated abuse better. Meanwhile, aluminum has its limits and dents more easily. Worse, enough repeated hits in one spot, and it can even crack. There is also a quirk related to friction. Because aluminum is softer and more malleable, it sort of grabs at rocks, so you hang up more easily. Meanwhile, steel simply slides right off them.

The bottom line is this: get aluminum to protect your car against the occasional scrape. But for anything serious, steel makes more sense.

A few other things worth chewing on

But that's just the short version. The long version actually involves a couple of other factors. One of them is cost. Steel usually costs less up front, so if cash is tight, that pulls you its way.

Another bit is maintenance, which is actually a side effect of steel's tendency to rust. Even if it's protected with powder coating, it can chip when a rock smacks it, leaving bare metal exposed. So every so often you may have to sand the rust off, then repaint the steel to seal it back up. Some folks also brush on a rust inhibitor, a coating that slows corrosion down. But you don't have to worry about most of this as aluminum skips most of it — in fact, you can ride around in a raw finish without much worry.

There is also the repair angle, and it's here that steel actually pulls ahead. If you bend a steel plate, you can usually just hammer it back into shape. But aluminum is fussier since it tends to crack under repeated stress, especially on the same spot. Whatever you pick, it's worth noting that both options are better than driving without a skid plate at all, as they protect crucial components like the engine oil pan, differential, and transmission.

That said, the differences in real-world performance might be narrower than what the material science may lead you to believe. YouTuber GX460 Off-road, an enthusiast who tested both metals on the same rig, found that the aluminum got gashed up just as badly as the steel. He concluded that he'd rather go all-aluminum next time purely because "it's a lot lighter." So if you're still torn, the honest move is to spec for the trails you actually run.