Comment on Do you need to adjust your speedometer if you change the size of your tires?

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Kecessa@sh.itjust.works ⁨4⁩ ⁨weeks⁩ ago

I don’t it because the 14" and 15" tires should have a different second number to their measurement to compensate, the manufacturer wouldn’t recommend installing tires that will make your speedo different depending on your wheel size.

First number is width

Second number is height of the sidewall as a % of the width

Third number is wheel size

So for example my summer tires are 255/45R20, my winter tires are 255/55R18, increasing the sidewalk height from 45% to 55% of the 255mm width compensates for the wheels being 2" smaller

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