[mpg_numbers_guy]

Keep in mind that since the wheel is closer to the center than the tire, reducing the weight of the wheel will have less effect than reducing the weight of the tire. On the highway you probably wont notice a difference in weight, there it doesn't really make much of a difference. I've loaded my Insight down with hundreds of pounds of stuff for traveling to college, and it doesn't make any difference in a fuel economy on the highway at all. Hills may be slightly slower, and the car may coast little faster and further down the hill, but the fuel economy remains unchanged. Weight reduction helps around town, aerodynamics helps on the highway. If you can get both, that's great, but that really depends more what kind of driving you do the most.