15 inch wheels

[1cheap1]

I have my 2nd 1995 Mazda Protégé lx 5speed with stock 13 inch rims and wheel covers. I saw some 98? 15 inch Enkei Mags with almost new tires. If I get these how much of an adjustment would I have to make to get my mpg correct? Was thinking maybe to visit a speedo shop to put in a gear to bring the speedometer to be correct.
The mags would raise the car however now I get 51 mpg on CC on the freeway so don't know if this would mess up my aero or would be just a trade off. Total would be about $500.00.

[theholycow]

What size tires are on your 13's and what size tires are on the 15's? Can't do a speedometer effect calculation without those numbers to feed into a tire size calculator.

How's your gearing? Does it match your driving? Like, do you have short, close ratios and drive in the city? Do you have highway gearing but drive in the city? Do you have wide ratios and a tall 5th gear and drive on the highway a lot? Or, do you lack the tall highway gear that you need for all your highway driving?

[1cheap1]

never mind, found the info that helped at automobile-catalogue.com