My dream G has 37" tires spinning around portal axles...
It will be far easier to pose and maneuver in the G500 4x4², a prototype of which we just drove. Daimler won't yet officially confirm series production, but with more than 100 units of the hyper-expensive 6x6 having been sold—far beyond expectations—before production ended, the potential for this similar new model is considerable.
The exclusive, common denominator between the G63 AMG 6x6 and the G500 4x4² is the portal axles, which use gears in the hubs to allow the axle to sit higher than the wheel centers in the name of increased ground clearance. The result is a vehicle that can clear 17.7-inch-high obstacles, versus the 8.3 inches of a stock G, as well as ford water up to 39.4 inches deep. The front and rear tracks are also wider by 11.8 inches, and while the standard G-wagen is relatively narrow, this variant comes in at 82.7 inches wide—still not so much that urban driving becomes a chore. On the other hand, its height of 88.6 inches will render many parking structures forbidden territory.
The regular G-wagen seems hard to beat off the road, but thanks to the portal axles, the 4x4² pushes the boundaries of capability to new extremes. We tested the prototype in a half-dry riverbed and on steep, rocky slopes that forced the regular model to throw in the towel—the mega ground clearance and the massively superior approach, departure, and breakover angles of the 4x4² allow for scrambling over even the gnarliest terrain. And thanks to the wide track, it feels stable and planted, with a tip-over point virtually unchanged from the basic G. Helpfully, you can opt for off-road-sized 37-by-12.5-inch mud-terrain tires on 18-inch beadlock wheels; these can be swapped out for 325/55 rubber on 22-inch wheels for on-road pursuits.
More of this article here:
http://www.caranddriver.com/reviews/mercedes-benz-g500-4x4-prototype-drive-review