How do you change the I.C when swapping the factory 16" wheels and tires on an I touring to the 17" wheels and tires from an s touring? do you have to change the I.C to compensate for the difference in diameter? Thanks

 

Assuming you put the correct tires on the 17" wheels, there will be no difference in diameter.

 

What size are your 16" tyres?

example, 205/55/16 equals 205/45/17 or 215/45/17