Originally Posted by StockerFX4

FWIW, I do reset my mileage calculator on the truck at every fillup, and I use an app on my phone to calculate mileage. The truck consistently reads 1L/100km optimistic. So if the truck thinks I am using 15L/100km, I am actually getting 16L/100km.

Also, I have read all the replies, and again, I still don't think it adds up. Maybe LaBrash can do some experimenting. I have tested my trucks speedo against my gps, it is consistently reading about 8kph below what I am actually doing. If you look at my mileage calculations compared to the truck, it looks to me like the truck is perhaps confused as to what my actual speed is. It would explain the error in the gas calculations. I have never seen a car that reads too high. I think personally LaBrash's truck will read closer to reality in terms of speed with the new tires. Even with the recal, lets face it, the bigger tires will still put him in the range of variation for the average car speedo. It certainly won't account for 30% poorer gas mileage.

Rotating mass is a bitch for acceleration, but once it reaches speed, it no longer has an effect. WOT acceleration is only 10% less efficient than even partial throttle opening, so I don't see the weight having a huge effect.

Rolling resistance is a problem too with the new tires, but again these are only slightly more aggressive A/T tires. I have seen at least two other threads where people put the same tires as LaBrash and lost max 2mpg, which is only like 1L/100km diff.

Maybe the recal will help, but unless he gains about 6mpg from it, something doesn't seem right to me.

I should have mentioned in the earlier post that I average 16L/100km in the city. I easily get 11L/100Km on the highway doing 110kph, or approx 68mph

Originally Posted by LaBrash

I bought the truck from Dams.lol.......on 104th and they have bent over backwards for me, so far 100% all good......

Originally Posted by McCarthy

My 2012 5.0 in its first 500km is averaging 15.6L/100km... not even remotely broken it yet either. But i AM taking it quite easy on the throttle until about ~1200KM's. Which sucks because all i want is to hear the 5-oh at full song...

EDIT: This is 65/35 city/highway

Originally Posted by McCarthy

Thought i'd update... I'm getting 18l/100km 70/30 Highway city. This is annoying. that's ~13MPG for our friends to the south.

Originally Posted by f150man3.5

Considering the winter gas and weather, your mpg's are 3 mpg under what your truck is rated. I believe 16 avg for your truck.

Originally Posted by mrgooden

My avg over the last 3k miles is 19.1, Highway 22.9. I also drive to work 27 miles one way.

Richard