i had my 2016 Ram 1500 3.6 litre pentastar leveled and replaced the tires with 285/70/17 and have a k&n cold air kit on the truck. Since I replaced the tires my gas mileage has gone from 23 mpg to 12 mpg. Any ideaas what is causing this decrease in mileage?
Are the tires the same size as your old ones? My truck had 35/12/20s on it when I bought it and my mileage was 10-11 mpg I had the computer programmed for my tires and it improved now I get 14-15 around town and 19-22 hwy depending on how I drive. Also I increased my tire pressure I was running 45 psi now I’m at 55 tires go up to 80psi for heavy loads. I running nitto exo awt tires and I love them!
I noticed that my mpg was off with the bigger tires but also the shift points we off too. Everything is running off the computer so with the wrong tire size the computer thinks the truck is going slower or faster and shifts according
If your tires are bigger than the ones you took off, your mileage will go down even if hand calculated! The odometer will be off. You can go to a known e-retailer like tire rack and get the runout of each tire. Divide the old tire's runout length by the new tires runout length and multiply that ratio to your odometer reading to get mileage. Then you can calculate miles per gallon.