Gear Ratio Calculator US
| * auto = D in an AOD (1:1) * AOD is calculated at .70 transmission ratio * 5 speed is calculated at .80 transmission ratio * Many late model vehicles have a taller overdrive ratio, such as Toyota Tacoma & Tundra with 6 speed Auto have a .58:1 overdrive. Use 1:1 RPM x .58 = RPM | |
| This table represents the recommended RPM range @ 60mph. Note: When you enter the desired gear ratio, new tire height and 60mph into the calculator on the left, the RPM range for your vehicle should fall between the values below. Example: If you have a 6 cyl vehicle with an Auto transmission without overdrive your RPM's should fall between 2000-3000 at 60mph. If you have 35" tires with a 4.88 gear ratio your RPM range will fall between the desired 2000-3000 RPM's. |
| 4 cyl | 2200-3200 |
| 6 cyl | 2000-3000 |
| small block | 1800-2800 |
| big block | 1600-2600 |
| GM Duramax 6.2L | 1800-2800 |
| Ford Powerstroke (non-turbo) | 1600-2500 |
| Ford Powerstroke (turbo) | 1400-2200 |
| Dodge Cummins Turbo Diesel | 1400-2200 |
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