RIM/TIRE size for v6 with out decreasing mpg?

[NismoPWR]

Hey guys srry if i double post this but i havnt found a good answer for want i want. Im interested in getting new rims. i currently have the stock 17" alloy rims. I remember when i put rims on my old car and bumped it up to 18" i lost about 40 miles on a tank compared to the stocks. I also felt bumps a lot more. Any feedback on low pro tires ? Any specific rim/tire size that increases performance/ gas. This my first car that i bought my self and i want to make it as personal as possible. thanks guys. BTW i tried to use the rim calculator but it wasn't much help for the answers i was looking for.

[digitalbow]

Maintain stock diameter.
Lightweight rims will contribute to increased gas mileage, regardless of diameter.

It is true that a smaller diameter can help with mileage, but so can a larger diameter. It all depends on the driving situation. Hills vs. flat terrain. Highway vs. city driving. That's why I suggest to just maintain stock diameter. Years of mechanical engineering have allowed car manufacturers to fit their vehicles with wheel/tire combinations that give you the best-fit fuel economy based on combined city and highway driving.

Now, if you ONLY drive on the highway, sure - oversize.
But chances are that you will be in situations where this slight advantage is totally countered with the effort needed to turn the wheels (for example, moving from a stop). This is an interesting topic, and it doesn't really get asked much. There are so many other factors as well, pertaining to wheel and tire width, tire compound type (surface) and tread design.

Your stock size is 215/55/17 on 17x7.5 wheels.
If you're thinking about stepping up to an 18 for the mere aesthetics but want to maintain diameter, look for a lightweight wheel in the same width and offset (7.5", +45mm) as OEM and try a 215/50/18 tire.

[D-Roll]

I have 18x7.5 rims with a 48mm offset (35-40 mm offest is better) and 225/45/18 tires

[mcheddadi]

I have my 19x8.5 +40 wheels on with some nice 245/40/19 size rubber

[NismoPWR]

thanks guys i'm probably gonna go with the 18" with the low pros....hopefully i don't feel the bumps too much....been losing sleep tryin to find out what rims the gray fox marketing turbo'd altima has.

[KillerCoupe08]

Will a set of 235/55/r17 tires fit on the stock rims without bulging the side walls.they are 7.5 width right??? D-Roll what gauge wire did you use for your ground wires and does the 8 gauge work the same as 4 gauge???