Gear & Speed Table Calculator

What this number means

Single-number calculators answer single questions. The table answers the trail question: in low range, second gear, at 2,000 RPM, how fast am I actually going — and is that the speed this obstacle wants? It is also how you spot a useless gear (some first-gear-low combinations move at walking pace divided by ten) and a missing one (the jump from 2nd to 3rd low that strands you between too slow and too fast).

What to change next

Read the low-range column for your working gears — usually 1st through 3rd. If 1st-low at idle is above ~1 mph on a manual, clutch life becomes the budget line. If the gap between adjacent low gears is more than ~45%, plan your line around the gear you have, not the one you wish for.

Worked example

JK Rubicon, NSG370 6-speed, 4.10s, 32-inch tires: 1st low at 2,000 RPM is 2.4 mph, 2nd low is 4.1, 3rd low is 6.2 — a tidy ladder. The same Jeep on 37s stretches every rung ~16%: 2.8 / 4.7 / 7.2. Bigger tires don't just cost crawl ratio; they space out the whole ladder.