The reason you would save gas with the 185/65 14 would be because you would be changing the effictive gear ratio. What the means it would be like changing the final drive ratio. Bigger tires lower gear ratio, more savings in fuel. shorter tires will raise the factory final drive ratio. On the highway is were you would see the savings with the taller tires. Light to light the shorter tires would be more effective. With the taller tires you would be changing the ride quality as well. A taller sidewall compared to stock will make the ride more comfy. I have looked at most tires as we need to change the rears. 98% are 30,000 mile tires just like stock. It is hard to find the factory tires with more than 30,000. I just bought a set of Japanese tires with a 65,000 mile tread life. One stipulation, I choose a taller set of rear tires. (I am an old hot rodder) The tires are 205/60/14. Yes they fit fine and with this selection the tires were more readily availabilty.