I put a set of Michelin M&S tires on my truck last week and the overhead has gone from 19-21mpg non-towing to 11- 11 1/2. Same size as the Generals. 70lbs front and 75 rear. The only other mod I installed was a True Flow XDI air filter which boosted the power and torque noticeably. I doubt that had anything to do with the mileage because I had over 1000 miles on the new tires before the new air filter. Is it the tires or has my overhead gone completely nuts??
you need to hand calculate the milage....and probally got some bad diesel which is the problem 50% of times.....
Just filled it up so I will do the caveman calc. The overhead has always been just 1-1 1/2 mpg lower though. The station near my house is small but it has a lot of diesel traffic. No guarantee against bad fuel however.
There is no way that tires would affect mileage that much. The only way it would is if you got tires that were much taller and you didn't reset the pinion factor which would mean you are driving a lot farther then your odometer says you are...
My over head always reads 2-4 mpg better than hand calculating. And I have yet to see better than about 16 on the highway. I hear every body talking about getting 19-20 mpg on the highway, but I have yet to see it. Whats up?
F.Y.I you need to drop the tire pressure down to what the door jam on the drivers door says.........running too much air in the tires will not help....look on your door jam, i believe its 60-65 all around, it works much better.....trust me 100,000 miles in ten months.....tried it all....
