gas mileage with 17" & 18" tires

[clp]

I would like to know if I was to buy custom wheels, in a size 17" or 18", would they effect my gas mileage in any way? Also, how would each handle on the road? I have not decided on which size to buy, so if anyone has either size, give me some input on both, plez. Thanks.

[ramenboy...]

welcome to the family!check this outhttp://www.1010tires.com/TireSizeCalculator.asptheoretically, going to a different tire size shouldn't affect your gas mileage. as go up in wheel size, you try to keep the daimeter as close to stock as possible. that will keep the speedometer from reading too fast or slow. the only way it would affect your mpg is if the new wheels themselves are heavy.i'm running 235 45 17s on my vibe and the speedo is still dead on. my mileage isn't affected.good luck!and post pics of the vibe. i smell burning torches and stuff

[sagittarius]

It is not the wheel/rims that change milage. What really matters is the diameter of the tire that meets road. As diameter increases, revolutions decrease per distance traveled. This effects both gearing, and braking ability. As diameter increases, you are operating lower in the power/RPM band of the engine. As diameter varies from the stock programed tire, speedometer and odometer will also vary, thus altering mpg calculations. Also, As tire diameter increases, there are fewer revolutions of the rotor to stop the car in the same distance, thus brakes work a bit harder. Having matching tire diameter and traction becomes very important with antilock brakes and all wheel drive vehicles. As long as overall diameter is within 1/2" of stock, and all 4 tires are the same, there is no real issues.

[wyatt89]

Width would make a difference, you will get better gas mileage if you have a 185 tire than you will with a 235 because there will be less grip and rolling resistance.

[Sublimewind]

Quote, originally posted by clp »I would like to know if I was to buy custom wheels, in a size 17" or 18", would they effect my gas mileage in any way? Also, how would each handle on the road? I have not decided on which size to buy, so if anyone has either size, give me some input on both, plez. Thanks. The biggest effect on milage you will see will be due to the weight of each wheel/tire combo at each corner.. All valid points have been mentioned, besides weight... The typical weight of one of my Subaru wheels is 16-18lbs, which is really light for that size rim, add to it a tire and you end up at about 45-50lbs PER CORNER.. If that weight is lessened, you will see increases in many aspects of driving, the brakes will work better, you'll have better acceleration, and net better fuel economy, overall, due to less unsprung weight, less rotating inertia, and less angular momentium..