I'm trying to get some facts about lowering a full sized truck. For any of those out there that have "slamed" their trucks, but kept the same gears and tire sizes, did it affect your gas milage?

My intuition tells me no bc the cross sectional area of the truck stays the same, but what I don't know is if being lower to the ground prevents turbulence from being created under the truck.

Please try to keep answers factual or if you know of sources for info, please let me know.

Thanks

 

I doubt that lowering a truck affects the gas mileage. Usually when you lower a truck, most people put on different wheels and tires which may not be the same diameter as the stock set up, which could cause a change in gas mileage.

 

I dropped mine 2/5 and put 22s on that have the identical final diameter to stock, but no doubt weigh more and my end result was EXACTLY to the tenth of a mile per gallon same gas mileage. I get 12.3. Period. lol

 

I litterally just lowered mine and i am still babying it around both because i want it to settle well, and second b.c i need shims in the rear so i dont want to F up my leafsprings or diferential.
Give me about two to three weeks, and ill be able to let you know if it stays about the same or gets better with gas mileage.
-Patrick

 

And in the mean time my alignment is all jacked up so i wont get a good reading until i get it all straghted out. Goodyear service shop wanted 380 bucks to get the front alinged. I need 80 in camber kit parts, which is just four bolts, and they wanted 175-200 in labor to get 4 bolts installed.
I will let you know tho when i can give you an accurate mileage reading.
-Patrick

 

You're a perfect candidate to test my theory. Please let me know what you get!

Thanks

 

well i just checked my gas mileage when i filled up, Now i was really babying it around for a week b.c i didnt have my shims in and i didnt want to screw things up.
But im up to 13.4 from 12.8-12.9
That was around 550 miles since the last time i had filled it up completely so it should be pretty accurate. except that it wasnt how i normally drive.

I still havent aligned yet, but hope to do that in the next week.
But now that ive filled up i can measure it with this tank and see what i get.
-Patrick

 

Not to discredit your numbers, but how confident are you in ~.5mpg difference? I little wind can have that much affect.

 

I didn't see a difference in mine. I put wheels on first then lowered my truck about a year+ after-wards. I still get anywhere from 15-17 mpg depending on what shoes I wear ...Figure that's all gonna change soon though. Saving gas was not on my agenda when I lowered...Heck not even when I bought the truck.

 

Your gallery shows another truck! Or most likely I am senile and clicked the wrong button..

I am getting ready to go for 22s on my 06 XLT SC, and I want to keep the same identical diameter as my stock wheel and tires.

Did you put a 40 or 45 series tire on your 22??

Also, do you tow?

 

That is why i made a point of saying that it was more then one tank worth. (550 miles)
I also mentioned that for about 100 miles, i did not have my shims installed, so i was going easy on it so i wouldnt do damage to my differential, or leafs.

So with that being said, i will likely fill up on sunday and we will see how it goes, because i have since put my shims in so i have been getting into it a bit more. And today it was rainy all day so i had fun drifting around some corners at lights etc...

Later,
-Patrick

EDIT Oh and im seriously considering getting 4.10's by this summer, so i can let you know how much i loose or stay the same with those in. (still would have stock rims/tires)

 

Thanks for the update. Keep the info coming!

 

13.39825 mpg through the course of 434 miles

Still have yet to align, thats on tomorrow's list of things to do, so i anticipate it will only get better once im aligned properly again
-Patrick

 

Here are the ford numbers for the cam bolts F65z-3b236-bb you need 4
and F65z-3c178-aa you also need 4 of these they are 8 bucks for the bolt and 3 bucks for the washer Big 10 tires told me the same thing so i got them from ford and im going to install them today

 

with 656 miles, i got 15.14 mpg. With maybe close to 300 of those were highway miles.

But so far even with me flooring it as i used to, i think im getting .5 mpg gain overall.
-Patrick