True speed
Shows actual speed for any indicated speed, since a taller tire travels farther per revolution.
Speedometer correction
Check your Tacoma speedometer error.
Compare your stock and new tire size to see how far off the speedometer reads and your true speed at any indicated speed.
In short
Calculates true speed and speedometer error from a change in tire diameter.
- Larger tires make actual speed higher than the speedometer reads; smaller tires do the opposite.
- Notes that regearing does not fix speedometer error because the speed sensor reads at the wheel hub.
What it does
How this tool helps.
Percent error
Reports the speedometer error and flags whether it is inside the roughly 3 percent safe window.
Gearing note
Explains that a regear does not change speedometer error; only tire diameter does.