[on2]

I have a dilemma. I have a 2013 Honda Accord Sport. From the factory, it is equipped with 18x8 wheels that weigh in at a hefty 29 lbs. each. The OE tires are 235/45/18 Michelin Primacy MXM4 and are 26 lbs. each for a total of 55 lbs. per corner.

For better fuel economy I plan on changing the wheels to some much lighter weight wheels.

Cost aside, my questions are...

1.) Which wheel diameter uses less fuel between 18" and 19"? The 18" and 19" wheels I am looking at are both around 19 lbs. Assume both wheels have the same width and aerodynamics and the tires fitted are the same weight (which they really are to my surprise I checked the specs on tirerack.com).

2.) Which tire size uses less fuel between 225/45/18 (possibly 225/40/19) or 245/45/18 (possibly 245/40/19)?

The 225 section width tires weigh less at 22 lbs. each, have less rolling resistance due to less section width, but is effectively a lower gear ratio thus increasing the engine revs at cruising speed.

The 245 section width tires weigh more at 25 lbs. each, have more rolling resistance due to more section width, but is effectively a higher gear ratio this decreasing the engine revs at cruising speed.

So which combination of benefits is better for fuel economy?

I know that 17" wheels or less is the best in terms of weight for fuel economy but that size looks to small on this car. There are 18" wheels that weigh only 16 lbs. each. Equipped with 22 lb. tires that's a total of 38 lbs each corner a savings of 17 lbs. each corner for a total of a whopping 68 lbs!

Thank You