When Salmon Nortje created the Downhill Mountain Bike, the usual process was not followed for its conception. The designer began by drawing up a fascinatingly futuristic form, expressive and beyond the typical parameters. This is what inspired the look of the conceivable conveyance that you see here.
The exaggerated lines were drawn back to make an engineered frame for the two-wheeler that's a great deal more fluid than what you're accustomed to seeing; the down tube takes a lovely S shape, the seat and chain stays are curved, and so is the top tube. It's this last feature that becomes the signature of the Downhill Mountain Bike. It's strong enough to support the weight of the seat and cantilevers out with a graceful curl.