Gear Ratio Calculator
Calculate final drive ratios, speed at redline, and cruise RPM for any gear combination. Choose a transmission preset or enter ratios manually.
Transmission
OD
Leave unused gears blank. Ratios below 1.00 are overdrive gears.
Rear Axle Ratio
Tire Size
Overall tire diameter in inches (not rim size)
RPM & Speed
Best highway gear: 4th(overdrive)
2,026 RPM at 65 mph · final ratio 2.60:1
Gear Results
| Gear | Trans | Final | @ Redline | RPM @ 65 mph |
|---|---|---|---|---|
| 1st | 3.059 | 11.41:1 | 43.8 mph | — |
| 2nd | 1.625 | 6.06:1 | 82.5 mph | 4,730Very high |
| 3rddirect | 1.000 | 3.73:1 | 134.0 mph | 2,911High |
| 4thOD | 0.696 | 2.60:1 | 192.5 mph | 2,026Ideal |
Highway RPM Snapshot
2nd82 max
4,366 / 5,093 RPM
3rd134 max
2,687 / 3,134 RPM
4th193 max
1,870 / 2,182 RPM
Bar shows the 60–70 mph RPM range. Left column = 60 mph RPM / right = 70 mph RPM.
Current Setup
Transmission4L60E (4-spd OD auto)
Axle ratio3.73:1
Tire diameter28.00"
Redline6000 RPM
Cruise RPM Guide
Lugging
< 1,600 RPM
Risk of detonation, excess heat
Ideal
1,600–2,800 RPM
Best fuel economy and longevity
High
2,800–3,500 RPM
Acceptable, slightly thirsty
Very High
> 3,500 RPM
Poor fuel economy, engine wear