A great book that explains the science behind the equipment used for four-wheeling. This book starts out with the basics of mechanical advantage: the lever, the pulley, the wheel and axle, and the inclined plane. It progresses into traction efficiency of various terrains, cone of support and wheel spin factors, and rolling resistance for various terrains and grades. The author then gets into how to drive on various terrains based on these various mechanical and physical factors. There is an extensive discussion of winches including how to use them. He talks, for example, about the origin of the recommendation to keep at least five wraps of cable on the winch when pulling, and shows the difference between well-oiled cable and dry cable. There are even illustrations of how to pull stumps efficiently with a winch. This book is a bit of a dry read, but it is jam-packed with engineering reasons why things work as they do. There are interesting things like his discussion of early four-wheelers experimenting with agricultural implement tires to get flotation on sand. There are great black-and-white photos of flat-fenders and CJs on white-wall tires.
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This book is out of print, but used copies can be found. I couldnít find any on-line reviews.