Saw a truck around town today with a ridiculous lift kit and chunky off-road tires that were clearly much larger than factory standard, and it got me thinking; if you install this kind of modification in a car, do you need to adjust the speedometer to compensate? What about the odometer?

My logic is the only absolute measurement the car has is how fast the wheels and drive shaft are turning, so presumably there is some sort of multiplier - 1 revolution = X meters - that is then used to show speed and track distance travelled, but that factor would need to change if the circumference of the tires did

  • Successful_Try543@feddit.org
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    11 hours ago

    I know, but still the circumference differs. It’s 195/60R15 vs. 185/65R14

    Comparison

    Obviously, the 10 % difference are just a feeling.