Originally Posted by pastorscott
so I have 30in mud tires 2 inch lift...2.5 5speed... according to my Speedo im getting 12MPg.. now with figuring in tire size would my MPG be actually higher or lower
First 30" tires did not come stock from factory I don't think with the 2.5L. check the White sticker on the Drivers door it should tell you what the stock tire is probably anywhere from 215/75 would come on a 4cyl stock I think could be wrong.
Next you have to determine as one of the posters said is to check the speed against GPS if larger tires where put on to replace the smaller stock tires then speedo will read slower than you really going 55 speedo 60 GPS.
Next is to find gear ratio more than likely your still running 4.10 gears as there would be no reason to change out the gears for such a small tire difference. Look on the rear axle differential there is a tag that should say 4.10 on them.
Once you determine your tire and gear you can go get the correct speedo gear.
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Should read 38 tooth gear if your still running 4.10 gears.
I know for a fact you can get better MPG with the 2.5L I had 33" with 4.10 and got 17MPG.