by Quadratec
Changing your Jeep’s tire size or swapping out the ring and pinion gear ratios means your factory speedometer will no longer read accurately. When your drivetrain geometry changes, the vehicle’s internal speed calculations are thrown off. Using the Jeep speedometer gear tooth chart below matches your exact axle gear ratio and tire diameter to identify the precise replacement speedometer gear you need for accurate calibration.
Note: If your Jeep is equipped with a later-model electronic speedometer rather than a physical gear setup, physical gear replacement will not work—the vehicle’s computer system must be digitally reprogrammed for the new tire size and gear ratio.>
Why Accurate Speedometer Calibration Matters
Keeping your speedometer accurate is critical for both on-road driving and off-road performance. Correcting your speedometer ensures true speed and distance. It restores accurate overall speed readings and fixes odometer distortion so your total distance traveled is correctly tracked.
It also results in proper transmission shifting. This ensures the Jeep’s powertrain control module (PCM) receives accurate speed data to properly time automatic transmission shift points.
Helpful Installation Tips
Recommended speedometer gears are calculated using the tire manufacturer's published specifications for revolutions per mile (RPM). Keep in mind that factory speedometer gear variances can naturally fluctuate by up to 5 percent from actual ground speed.
Speedometer gears are quick and easy to install using basic hand tools. We strongly recommend replacing your old hardware with a fresh speedometer O-ring during installation to prevent fluid leaks.
| Tire Size | 44" | 42" | 40" | 38" | 36" | 35" | 34" | 33" | 32" | 31" | 30" | 29" | 28" | 27" |
| 5.38 Ratio |
34 | 36 | 38 | 40 | 42 | 43 | - | - | - | - | - | - | - | - |
| 5.13 Ratio |
32 | 34 | 36 | 38 | 40 | 41 | 42 | 43 | - | - | - | - | - | - |
| 4.88 Ratio |
30 | 32 | 34 | 36 | 38 | 39 | 40 | 41 | 43 | - | - | - | - | - |
| 4.56 Ratio |
28 | 30 | 32 | 34 | 36 | 37 | 38 | 39 | 40 | 42 | 43 | - | - | - |
| 4.10 Ratio |
- | 26 | 28 | 30 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 |
| 3.73 Ratio |
- | - | - | 26 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 |
| 3.55 Ratio |
- | - | - | - | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 |
| 3.07 Ratio |
- | - | - | - | - | - | - | - | 26 | 27 | 28 | 29 | 30 | 31 |
| Tire Size | 44" | 42" | 40" | 38" | 36" | 35" | 34" | 33" | 32" | 31" | 30" | 29" | 28" | 27" |
| 5.38 Ratio |
34 | 36 | - | - | 42 | 43 | - | - | - | - | - | - | - | - |
| 5.13 Ratio |
32 | 34 | 36 | - | - | 41 | 42 | 43 | - | - | - | - | - | - |
| 4.88 Ratio |
- | 32 | 34 | 36 | - | - | - | 41 | 43 | - | - | - | - | - |
| 4.56 Ratio |
28 | - | 32 | 34 | 36 | 37 | - | - | - | 42 | 43 | - | - | - |
| 4.10 Ratio |
- | 26 | 28 | - | - | 33 | 34 | - | 36 | 37 | - | - | - | 41 |
| 3.73 Ratio |
- | - | - | - | 26 | 28 | - | - | 32 | 33 | 34 | - | 36 | 37 |
| 3.55 Ratio |
- | - | - | - | 27 | 28 | - | - | - | 32 | 33 | 34 | - | 36 |
| 3.07 Ratio |
- | - | - | - | - | - | - | - | 26 | 27 | 28 | - | - | - |
