[exclusvmrreed]

Does the size of your wheels affect gas mpg? My 2009 R/T came with 18's from the factory but I upgraded to 20's. I checked the build info to confirm that it came with 18's and it did. So now I'm wondering if the computer still thinks the 18's are still installed. Any feedback is appreciated. Thanks


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[Hal H]

There would be a slight under-reading the 20" (OEM size) tire is .5" taller and the tire will rotate fewer revs:

716.1/ mi for the 18" vs. 703.5/ mi for the 20", for a difference of 1.8%

 

[ericlee9386]

For me going from a 22's to stock srt 20's showed no change in mpg.

 

[Xombiefighter91]

I believe it's more of the difference in weight which causes a change in MPG rather than the actual size of the rim.

 

[shaker0378]

If you change the rolling diameter of your rear tires, you should reprogram the computer for the new size. Otherwise your speedometer, odometer, etc will be off.
You can use a Diablosport tuner for this, or I'm sure a dealer could do it for you.

 

[exclusvmrreed]

Thanks for the input guys.


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