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JeffC 10-14-2015 10:53 AM

3.8L Engine 34x10.5-17 or 285/75-17
I've got a 2.5" lift and still have (and am keeping) stock flares and bumpers.

Most notably, I have the 3.8L JKU Rubicon and am looking for advice as to which of these wheel & tire combinations will leave me better engine performance?

Is there a notable weight and rolling resistance difference between these tires?

I like the "pizza" look but unsure what I gain and lose between these two sizes with respect to my 3.8L engine.

jadmt 10-14-2015 12:09 PM

not sure what 285/75-17 you are planning on using but generally that is going to be a heavier tire and also taller. the 34x10.5-17 is most likely going to be a KO2 as not sure who else makes that size. The KO2 in that size is really pretty light. I measured one at 52lbs. I know my 285/75-17 toyos were considerably heavier and taller so based on that the 34's will be more spunky.

I switch back and forth between my Toyo 35's that are within .25" of the 285 toyos for height and a few pounds in weight and when I put the KO2's on I feel like I turbo charged my 3.6L. strange thing is mpg is identical with either set up.

JeffC 10-14-2015 11:09 PM

Great reply, thanks. After reading about the KO2 lightness I thought my mind was made up but then with the mpg being the same I am confused all over again!

Any 3.8L engine experiences?

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