Help On Replacing Tires
 

Getting new tires on my 01 Blazer 4Dr LS. Stock tires are 235x70x16, but im looking to upgrade. The guy ay townfair told me the biggest he would reccomend I go is 245x70x16 which is a 29.5 in diameter with the Eldorado Sport Plus. Im wondering hoe badly this will affect my mpg, I get about 20 mpg on mine. Also would the spedometer be thrown off? The guy said it wouldnt with these tires but im looking for some more firsthand advice.