# speedo corrections when changing 17" to 18"



## Txgoat (Oct 20, 2005)

With regards to the FACTORY tires and wheels, is there a heigth difference between the 17" and the 18" tires/wheels or is it okay to switch them off without changing the speedometer readings?


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## SLOGTO (Jul 5, 2006)

The overall diameter of a 245/45R17 is about 25.68", a 235/40R18 is about 25.40", the difference of .28" is considered by most to be nominal and OK to switch between the two sizes without recalibrating the speedo each time.


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## EEZ GOAT (Jul 9, 2005)

i have 245 40 18's all the way round. what should i do?


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