Enter your Transmission Low Gear Ratio, Transfer Case Low Range Ratio, and Axle Ratio to calculate your Crawl Ratio, Distance per Revolution, and Performance Rating. Running a Dual Transfer Case? Add your second ratio and Tire Diameter for the full picture.
Crawl Ratio
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Distance per Revolution
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Performance Rating
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Best For
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Transfer case ratio is the gear reduction provided by the transfer case in low range. It multiplies the torque from the transmission to provide better control at low speeds for off-road driving.
Crawl ratio is calculated by multiplying transmission low gear ratio × transfer case low range ratio × axle differential ratio. For dual transfer cases, multiply by the second case ratio as well.
For technical rock crawling, ratios of 70:1 to 100:1 are ideal. Higher ratios (100:1+) provide excellent control for extreme terrain, while 50:1-70:1 works well for moderate crawling.
Distance per revolution is how far your vehicle moves forward with each complete rotation of the engine. Lower distances mean more precise control and slower speeds for technical terrain.
Dual transfer cases provide extremely high gear reduction ratios (often 200:1+) for the most technical terrain. They're typically used in competition crawling or extreme off-road situations.
Larger tires effectively reduce your crawl ratio by covering more ground per revolution. Smaller tires increase the effective ratio, providing better low-speed control but reducing ground clearance.
4Hi (high range) typically has a 1:1 ratio for normal driving speeds, while 4Lo (low range) provides gear reduction (usually 2:1 to 4:1) for maximum torque and control at low speeds.