Crawl Ratio Calculator
How much the tires are reduced in 1st and 4-low. It is just three numbers multiplied.
What it does
crawl = first-gear ratio × transfer-case low × axle ratio. No tire diameter in this product — that is RPM at speed.
How to use it
Enter first gear (from the transmission spec), 4-low ratio (often 2.72, 2.62, 4.0…), and axle ratio.
How to read the result
Higher crawl means more torque at the hub and slower wheel speed for a given engine speed. Forum folklore cites 50:1 or 70:1 as “good.” Those are not a standard. We show the number and the three factors. You decide if it is enough for your trail.
What this does not calculate
Does not include a low-range auxiliary box unless you fold it into one of the three inputs. Does not know tire size.
Does not grade your setup as trail-ready.
Questions
- Do I include tire height?
- Not in crawl ratio. Taller tires reduce mechanical advantage at the ground; that shows up in RPM at speed and in how hard the motor works, not in this product.
- Is 50:1 the minimum?
- No published minimum we will treat as a rule. Rock-crawler culture likes high numbers; a stock truck may sit in the 30s and still leave the pavement.
Related tools
- Regear Calculator — Restore Cruise RPMTaller tires are like a taller gear. We calculate the ratio that puts cruise RPM back. We do not tell you to buy 4.56.
- RPM at Speed CalculatorHow fast the engine is turning at 65. Diameter and gears, not a guess from a forum chart.
- Reverse Tire Size FinderYou want about 33 inches. We list real sizes that actually sit there — not a fake 273/61R20.
Estimate — not a fitment approval.
