I got to go "four-wheeling" with members of the Minnesota Four Wheel Drive Association at their event last weekend. My son and I got into what could be called "extreme" four-wheel-drive events in 2001, with an old truck I got from a neighbor for $200.
Those days are gone, and so is the old truck. After many upgrades (and some left to do) I have given that 1974 Dodge to my nephew, and have built this 1996 Dodge. It has Ford one-ton axles, a shortened frame, and 39-inch tires.

In spite of how "unstoppable" this truck looks on the trailer, I had all I could do to keep up with the two guys in these two red Jeeps. Paul is standing there talking to John. Paul's Jeep, in the background, has 35-inch tires and a manual transmission. John's Jeep has 33-inch tires and a 9,000-pound winch (winches are rated by pulling power) which he used to extract my truck from soft sand on a log-strewn hill climb. I got stuck where John and Paul drove right up the hill and over the logs.

The fact that these guys go everywhere, over every obstacle on the trail, and do it in street-legal vehicles that they drive to and from the event, is a testament to their off-road skill and experience. It also proves that the biggest truck with the biggest tires is not always "the best" off-road machine.
We saw another red Jeep driver who did not do well on a different hill climb, and rolled the Jeep over on its side. The rules of these four-wheel-drive events mandate roll bars or steel roofs on all vehicles, and this is why.
Getting this Jeep off its side required a winch pull from this blue Jeep. The synthetic winch line (looks like blue rope but is much stronger) was run through a pulley attached to a tree and over to the rolled Jeep. A special wide nylon strap, called a tree saver, is used to connect the pulley to the tree, preventing tree damage. A slight tug from the winch line had the red Jeep "shiny side up" in about 60 seconds. The engine started right up, body damage was minimal, and the guy continued up the trail.
This picture was snapped a few seconds AFTER the big Chevy truck was spinning all four of its 40 inch tires in this mud hole. In spite of the sign that says the hole is "not very deep," it looked like this truck was not getting out of the hole without a pull from another truck "on shore"-- but it did crawl out.

And then Paul drove his much smaller Jeep with much smaller tires through the same mud hole -- with absolutely no drama and no tire-spinning.