Crawl Ratio Calculator

Your details

The gear reduction of your transmission in first gear. Common values range from 2.5:1 to 4.7:1. Find it in your service manual or transmission spec sheet.
:1
The low-range reduction of your transfer case. Stock values are typically 2.0:1 to 4.0:1. Aftermarket crawl boxes can push this to 8:1 or higher.
:1
Your differential ring-and-pinion ratio. Common off-road choices are 4.10, 4.56, 4.88, and 5.13. Calculate it by dividing ring-gear teeth by pinion-gear teeth.
:1
Measured outer diameter of your tire (not the sidewall number). A 33-inch tire is a common stock size; 35 and 37 inches are popular upgrades.
in
The engine speed you want to evaluate. 1,500 RPM is a typical low-speed crawling idle. Lower RPM = slower, more controlled speed.
RPM
Crawl ratioModerate
44.6:1

Total drivetrain reduction in 4-Low first gear

Distance per engine revolution2.324in
Vehicle speed3.3mph
Vehicle speed (km/h)5.31km/h
Performance ratingModerate (light trails)
44.6 :1
Low<30Moderate30-50Good50-70Excellent70-100Extreme100+

Crawl ratio 44.6:1 - Moderate (light trails)

  • Your drivetrain multiplies engine torque by 44.6:1 in 4-Low first gear, which means the ring gear turns once for every 44.6 engine revolutions.
  • Your vehicle moves only 2.32 inches per engine revolution - giving you extremely fine throttle control over obstacles.
  • At 1,500 RPM your ground speed is just 3.30 mph (5.31 km/h), allowing near-stationary obstacle negotiation.

Next stepA crawl ratio of 44.6:1 is solid for most off-road terrain. For dedicated rock crawling, aim for 70:1 or higher by re-gearing the axles or adding a crawl box.

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