went up in tire size and for years never changed the gears. I always had to figure out how far I actually travelled as compared to what the odometer read, and also same for the speedo. But now I put in 4.88s and am wondering if now my odometer and speedo should be "on" again. With the 4.10s and 33" tires Ive been figuring that for every mile I actually travel I only register 0.75 miles , which i figured by driving 1 mile on the highway )from mile marker to mile marker) and looking at what registered on the odometer. Now ive been using this same logic with the 4.88s and calculating my mileage at about ~20 combined. If changing the gears made the odometer accuraate again my mileage is WAY worse....