i've heard that bigger tires and i dont mean like 36''ers lol but like say from a stock 16-17'' to the bigger 19-20'' would increase mpg a little. can anyone clarify this for me?:o

 

While a taller tire will make your engine rev a lower at any given speed, this DOES NOT automatically mean you will get better mpg. You might see a small gain in some instances....

...but...taller, wider tires have more rolling resistance and more wind resistance.

Also, most motors run efficiently at an rpm that is close to the peak torque. If you drop the rpm too much, the motor is struggling and needs more throttle to push a big heavy truck with tall tires.

 

wow nice answer, thanks! lol.

 

when i had 33's i made 15mpg on the highway. i went to 35's, i now make 18-19 mpg on the highway- in town i made 10, and comparitively now i make 12- i've also paired the larger tires with a tuner, so that may have helped the engine- without the tuner, i would expect my in town mpg to drop with the larger tires due to the larger rolling resistance, and added weight needed to rotate

 

interesting lol well im not going offroading so 33'' are a bit out of the question. right now i get about 20mpg on the highway with the stock 17'', i was wondering if going to 18 or 19 would be any beneficial.

 

you are talking about rims and tires separately like that would make a difference. You can get the same size tire for any of those sized rims, the only way that a different rim size should make a difference would be if one is heavier than the other. Balog and Dirt Bike Dave are talking about tire size. a 33'' tire is a 33'' tire.

 

Just a thought for you...

Compare the savings in gas to the extra expenditures in buying these more expensive tires. Depending on how often you have to replace, cast, and fuel savings, it may be more cost effective for you to keep your less effiecient tires for the savings in tires.

I would graph both expenditures on the same plane, and see what you would gain/loose.

 

Actually, unless you are careful, going from a 17" wheel to a 20" wheel will kill your gas mileage. Generally speaking, larger wheels weigh quite a bit more, unless you can find a nice forged aluminum set (cast wheels weigh more). If your factory 17's weigh 28# apiece and the 20's weigh 36# apiece, you are going to take a decent hit on mileage due to the increase in spun weight. You must also factor in the weight of the individual tires you are thinking about using, because they too vary wildly.

Gary