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

  • Brown5500@sh.itjust.works
    23·
    8 hours ago

    Yes,you can use the tire size information to calculate the circumference of the stock and the new tires. The speedometer will be off by the same ratio as the difference in circumference. If the new tires are already installed and you don’t like geometry, use your gps to check the accuracy of the speedo at a few speeds