The stock front 110/90-18 is 81.037" in circumference and 25.8" in diameter. The 120/70-18 is 77.327" and 24.614". It is a low profile tire and is much smaller. That is why the fender looks like a dirt bike with the 120 tire. I have a 110/80-18 front as a 110/90-18 is not available in a radial. It is 78.317" in circ and 24.93" in dia. My fender looks bad also. :Sad:
The stock rear is 80.5" in circ. and 25.63" in dia. My 170/60-18 is 81.8" by 24.6". With the slightly larger rear tire and my Venture diff, I get 42-45 mpg at 75 to 80 mph on the highway. (stock engine). A 160/60-18 rear tire is almost the exact same size as stock, (80.3" circ and 25.6" dia).
The stock rear is 80.5" in circ. and 25.63" in dia. My 170/60-18 is 81.8" by 24.6". With the slightly larger rear tire and my Venture diff, I get 42-45 mpg at 75 to 80 mph on the highway. (stock engine). A 160/60-18 rear tire is almost the exact same size as stock, (80.3" circ and 25.6" dia).
