Ok haven't been on here in a long time. But my dad and I just recently bought used 2010 F150, he bought a XLT crewcab 6.5 box with the 5.4 and 3.73 gears he has roughly 15k miles on his and I have a Platinum crewcab 6.5 box with the 5.4 and 3.73 gears and roughly 26k miles on mine. We both were coming back from upnorth, highway driving, both had the cruise set at 70mph and he even called me to ask what I was running for RPM and it was the same. He said he was getting 16.9 and I was at 13.8. I filled up earlier and calculated out my MPG and the computer was pretty dang close. So my question is why such a big difference, one thing I came up with would be he has the stock 18" wheel where I have the stock 20" wheels. I would like the experience of everyone out there. We are both scratching our heads to why there is such a big difference.

 

Tires should not make that much of a difference at highway (constant) speeds, but rather city driving where you keep on spinning up that extra weight every time you accelerate.
There must be something else going on I would say, very hard to say what that could be, as a ton of factors can have an effect on gas mileage.

 

The stock 18's and 20's are very similar in actual size and diameter.

Any mods at all?

Are these trucks 4x2's or 4x4's? Does either have a tool box or any after market items that would add to the weight?

 

i remember my grandfather telling me a story about him and his brother going somewhere in a motor home once. It was his brother's motorhome, and he was always confused as to how my grandfather was able to get better mileage driving than he did.

my grandfather claimed that his brother stepped into it much harder getting up to speed, instead of using a lighter foot and taking longer to gain speed.

on a long trip using cruise conroll, you would think that it would eliminate the driver, for the most part at least.

perhaps the cruise control is set more aggressivly in the truck getting lower mileage?

that's a pretty big spread for "the same truck"

 

In my mind, this is the big question since they are basically the same truck. A 3mpg difference is pretty substantial in the grand scheme of things.

 

Was your dad behind you most of the time, following closely?

 

Both the trucks are stock, both have low profile tonneau covers and they are 4x4. My dad was maybe 20 miles behind me. We are both going back up Friday again so I will see how it goes again.

 

The Platinum has a lot of options that make it heavier than an XLT, and it takes more power to get those 20's up and going too.

 

swap trucks for a while.

might tell you something.

just a thought.

 

I would swap trucks but it is so nice having the heated seats in the winter here .

 

... let him drive it for awhile till it warms up, then switch

just wondeirng if your fuel mileage will follow you to his truck or not.

kinda nice to drive something different once and a while anyway.

 

Good idea.
Also, if he was 20 miles behind you, he could have gone slower. That will make a difference.
EDIT: never mind, just saw the "cruise set at 70" thing.

 

I'm not a huge fan of CC as a gas savings measure. It's no different than mashing down on the pedal and then letting off the pedal all the time. To me it's good when your foot needs a rest and when you're in a known speed trap.

The Plat may be a bit heavier and it may draw more power to keep the electrical load satisfied.

I think you have to start off the same way. Check tire pressures and ensure that each tire is aired up as per Ford's recommendations. Ensure that each truck has a similar amount of weight, ie, passengers, gear, etc. Get underway at the same time and remain in the same lanes.

Then again, we could all be waaay over thinking this.