Originally Posted by boostjunkie1
Go here and you will see the size difference. Take that difference in % and multiply that by how many miles you drive before filling up. This will be around 4% by what I can tell. Add what you get to your total mileage and that is the actual miles you have drove.
Example: You drive 250 miles before empty and then fill up at 19 gallons.
250 miles X 4% = 10 miles...... So that gives you 260 miles.
260 miles / 19 gallons = 13.68
Instead of: 250 miles / 19 gallons = 13.15
Little better. You also have to take into consideration the rolling resistance of the new tires + the weight difference + the fact that you have now numerically lowered your gear ratio. Around town bad ====== Interstate Good.
another thing after they play with what they call winter fuel you will lose fuel ecomny even if you don't do anything different. The combination change your ging to see a change in your fuel milage.