https://gearjunkie.com/4-wheel-bike-...49d02-22782825
"A titanium frame holds down four—count ’em,
four—5.5″-wide wheels, two in front and two in rear. That mammoth paw print provides massive float along the polar terrain.
The real engineering genius lies in the drivetrain, though. An 18-speed internal hub with Pinion transfer case gives Van Weelden “more range than mountain bikers with a triple chainring.”
Running this setup has two advantages: It keeps the gears largely out of the snow and ice that would otherwise confound a typical drivetrain.
It also allows the stainless steel chain to run through the center of the bike, powering a rear hub that rests between the two tires."