My gear ratio stinks (will larger diameter tires help?)

[SilentMatt]

I understand a bigger, heavier wheel will take more power to get up to speed, but does it take more power to maintain it?
My engine makes peak hp at 6400 rpm, so would that rpm put the lowest load on the engine? The issue is that the faster the engine spins, the more air gets drawn in and therefore more gas.

If you roll a small diameter wheel and a large diameter wheel on a level surface, the bigger wheel tends to roll further with the same amount of energy. This is probably due to rolling resistance and a flywheel effect. Not sure if this translates into real world, car efficiency though, just trying to brainstorm... The size difference between 185/60 and a 185/75 isn't that drastic. Did the LT(?) that had 15" rims get worse mileage?

I also dealt with Jeep mileage, I had a ZJ that I built a 6.5" lift for and put some 34" Swampers on. That 318 was thirsty to begin with, afterwards it was ridiculous. I was stationed in southern california at the time and gas was $4.50 a gallon...

It's also fact that high rpm equals faster wear on an engine.