so I have the worst mileage, but i have 19's whats the smallest I could go for getting good gas mileage for like road trips n stuff?

 

Do you actually get terrible mileage? Are your 19" wheels and tires larger in diameter than stock 15" wheel and tires?? If so you speedo will read low and you will record less miles than you actually drive therefore your mileage will calculate low. The difference in mileage between a 19 inch rim and 15" rim with the same overall diameter of the wheel and tire assembly (the way it is supposed to be done) is zero...assuming that the larger wheels and tires aren't heavier and do not make more friction..(arent wider) . SO.. A skinny stock diameter tire on a light wheel will deliver the best mileage. Oversize wheels usually means at least a wider tire (more friction) and usually more weight. My 18" wheel and tire combination dropped my mileage only 1.5-2 MPG after correcting the calculation due to the fact that my tires are 3.5% oversize in diameter...so for mine the impact of wheel and tire weight and width cost me 2 MPG. If I do not correct for having a larger overall diameter it would calculate a little more than 1.2 MPG less. SO uncorrected I would see a 3+ Mpg loss.

 

so since my wheel/tire combo is 4.3% oversize compared to stock, I should take my "(mileage * 1.043) / gallons" to calc my MPG?

that makes sense since Ive been getting about 27mpg city. so that means it should be about 28mpg which is closer to the advertised 30mpg city.

 

Bright observation!!!!

 

soo impressive, yeah becasue instead of like 30/35 i get like 25/30.. i think they are pretty wide 19's and weigh a decent amount. I was just curios on everyone elses thoughts, thansk for all the awesome info

 

I always get about 4 mpgs better when I run my steelies over the TRDs on long distance road trips.