Larger Wheels/MPG - Is it affected?

[72BlckButy]

Now I know this is the suspension forum but a lot of questions about wheels come through here so I thought I would post my question here. I was sitting around the house last night and had a question pop up:

If you upgrade your wheels to a larger diameter rim/tire, will your MPG be affected?

I know that on trucks with super large wheels/tires, since it takes less revolutions to go farther, I wondered if this was the same case for the lowered crowd. I also understand that it will require more energy to turn a larger dia. wheel. Most aren't concerned with their mpg but mainly the "cool" factor, but it was just something that I was curious about. I know that sometimes you have to change gear ratios (mainly for the lifted 35's+) and what not, but for a simple wheel/tire change has anyone noticed a change in their mpg?

Just curious what your experiences were; it's one of those questions you wake up and say, "Hmm..."