Guide
Crawl ratios, low range and portal hubs
How first gear, axle gears, transfer cases, doublers and portal hubs combine.
5 min readUpdated 9/9/2026
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Get to know your gearing.
Learn how transmission ratios, final drive changes, and tire diameter affect acceleration, cruise RPM, and top speed before you start swapping parts.
Guide
Speedometer calibration after tires, gears or portals
A practical workflow for tire changes, axle swaps and off-road reductions.
6 min readUpdated 9/9/2026
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How to Read Gear Ratios
A plain-English guide to understanding what first gear, overdrive, final drive, and tire diameter really do to vehicle speed and engine RPM.
6 min readUpdated 3/16/2026
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Gear Ratio vs Final Drive
A practical guide to deciding whether you should change the transmission ratios, the final drive, or the tire size when a setup feels too short or too tall.
7 min readUpdated 3/16/2026
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