A 1926 Fordson screw-drive tractor on display at the Hays Antique Truck Museum in Woodland, Calif.

Photo courtesy of Killiondude

Where would we be without the good-old wheel? It allows us to travel over hard-packed surfaces like dirt paths and paved roads with ease and speed, and it's been doing a pretty good job of it for thousands of years.

Unfortunately, our friend the wheel has never been a really great performer in mud, snow or water, because these media don't provide a firm enough surface to push against the way solid ground does. The lack of resistance with these surfaces is actually a hindrance to traversing through them.

But over the years, several vehicle makers have come up with a solution that appears -- well, downright screwy. In fact, it is screwy. These contraptions move through semi-viscous material like snow and mud in just the way a screw is propelled through wood.

In this article we'll explore how screw-drive vehicles work, their history and how they perform under off-road conditions that would make even a Humvee "say uncle."

If you're a faithful HowStuffWorks.com reader, then you know the "drill:" read the next page to learn about screw-drive vehicle design.