Choose the Rock-Trac® part-time 4WD system - one of the toughest four-wheel-drive systems known to mankind - and you're ready to operate in the most outlandish environments. Rubicon has an incredible 73.3:1 crawl ratio, allowing for a controlled 0.8 kph cruise up or down the rocks. The higher the number, the slower the vehicle will go. And driving slowly is the key to successful off-road driving, especially over rocks and rugged terrain.