Next time you’re on the highway, check out your surroundings. Take a long look at those semis, tractor-trailers, and 18-wheelers in the adjacent lanes, and see if you spot any spikes sticking out of their wheels. Have you ever wondered what those do? Well, the answer may be less interesting than you expect.
Semi-truck wheel spikes look like something out of Mad Max or Death Race, ready to tear through the sheet metal of anything that dares veer too close in an adjacent lane, but they’re actually there for a very banal reason: Rust prevention. They’re just little cosmetic covers, usually molded in plastic, that keep road salt and grime from getting onto the truck’s wheel studs and screwing up the threads.
Of course, that function — keeping the threads clear — doesn’t require the spike shape. If they’re just to keep road salt out, why spend on manufacturing to hit this specific taper? Is there some alternative reason for making them so pointy? Not really — sometimes spikes just look cool.
If there is an alternative reason, it’s the same reason you clicked on this article — spikes draw your attention. Specifically, on an 18-wheeler, they draw the attention of other drivers to the semi’s wheels. Those communicate lane placement and driver intent through their location and angle, giving information to adjacent drivers who may be distracted. They’re also a reminder that semis are big, powerful, and will absolutely win if you hit one.
Semi-truck wheel spikes are just simple corrosion inhibitors, meant to keep salt and grime from gunking up the threads on truckers’ wheel studs. The pointy appearance is just that — all appearances, a banal function given halfway interesting form. Still, try not to hit them if you can avoid it. You’ll lose.