Ok so the stock tire size is 235/(45)R17... If I get the 255/(40)R17 will it mess with the speedo? Plz fill me in because im bout to travel across the country and dont need any tickets :P Reason I ask is cause the profile is diffrent the the stockers... (45) (40)

 

Shouldn't be an issue at all. Its only three tenths of an inch differ in diameter. Well within upsizing spec.