This Off-Road Buggy’s Hydraulically Extending Frame Will Twist Your Brain

Yes, both pictures are of the same buggy just seconds apart.

byJames Gilboy|
Roxdawg hydraulic frame buggy

Look, man. There's no smooth way to introduce this: I just watched a buggy stretch out its frame to climb a boulder like an anaconda (supposedly) unhinges its jaw to swallow prey. If that weren't mind-melting enough, learning how the thing works dissolved what was left of my neurons. It's just soupy brainestrone up there now.

I'm talking about Roxdawg, the one-off prototype rock crawler with a hydraulically extendable frame. In off-roading, a long wheelbase lets you climb taller obstacles at the risk of dragging your underbelly on them. Having a frame that can almost triple your wheelbase from 68 to 207 inches fixes that problem in about the most complicated way imaginable.

"Roxdawd" hydraulic frame-extending buggy. WRECKED GEAR on YouTube

The Roxdawg runs off a 1.9-liter Volkswagen TDI diesel that, instead of powering a transmission, drive a pair of skid steer-style hydraulic pumps. They generate the pressure that pretty much the entire vehicle runs on, from the hydraulic rams that extend the frame's sliding beams to the ones that raise and lower the leading and trailing arms of the suspension. They have three whole feet of travel on their own, and that's before taking the long-travel struts into account. Also, the cab can tilt hydraulically to maintain balance.

The hydraulics power the drive wheels through a hydrostatic transmission that I gather works kinda like a torque converter. Hydrostatic motors on each axle can problem the Roxdawg forward or in reverse, under- or over-driving wheels as needed. The wheels themselves are bead lock-equipped and wear 42-inch BFGoodrich tires and are steered on both axles. Portal axles, I should add—a touch that barely manages to be a footnote in a build this extreme.

Roxdawg has been a 10-year project of iteration and tweaking, and the result is beyond description. You really do just have to watch it in action, it had me pulling faces even more contorted than its suspension and frame get. And if you can't get your fill, you can follow its builder on Instagram where he has plenty of videos posted. Remember what your mom always said: If you hold those faces long enough, they'll stick that way.

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