Enter your Transmission Low, Transfer Case Low, Axle Ratio, and Tire Diameter into the Crawl Ratio Calculator to find your crawl ratio, total gear reduction, distance per revolution, and a performance rating that tells you how your rig handles the tough stuff.
Crawl Ratio
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Total Gear Reduction
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Distance per Revolution
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Performance Rating
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Crawl ratio is the total gear reduction in your vehicle's lowest gear configuration. It determines how slowly and precisely you can move when rock crawling. Lower crawl ratios provide better control and torque multiplication for technical terrain.
Crawl ratio is calculated by multiplying transmission low gear ratio × transfer case low ratio × axle ratio. The result shows how many engine revolutions are needed for one wheel revolution.
Generally, 70:1 and higher is excellent for extreme rock crawling, 50-69:1 is good for moderate crawling, and 30-49:1 is fair for basic trail riding. Ratios under 30:1 provide limited crawling ability.
While tire diameter doesn't change the mathematical crawl ratio, larger tires increase the distance traveled per wheel revolution, effectively reducing crawling precision. Smaller tires provide better control for technical obstacles.
Yes, you can install lower transfer case gears or change axle gears. Adding an Atlas transfer case or regearing differentials are common upgrades that significantly improve crawl ratios.
Lower crawl ratios provide higher torque multiplication, meaning more torque reaches the wheels at lower speeds. This allows your vehicle to climb over obstacles with less engine power and better control.