I was running an FX4 SCAB with 285's with a very heavy foot and I was getting 12.5 to 13 in town and 15.5 on the highway. I am guessing that you have a 2wd by the mpg that you are getting.

 

Yeah 04 5.4 Ext cab 6'5" bed 2wd

 

I'm running P235 70 17r right now, got new tires, but just replaced with exact same thing as stock. I plan on 20s in the spring/summer next year and the size is 20"x8.5" so I want to run the same size tire that comes factory on the 20" OEM when I do. I want as many mpg's as possible.

 

it's all about the timing, like blue said he averages the same with the 87 tune as the 93 tune so maybe the 93 isn't the one you want


I only ran the 93 because I only use premium (all my vehicles are either boosted or tuned for it though)

 

20's won't be doing that for you...

 

Nope. My 305/50/20s cost me almost 1 1/2 mpg. But I love them.

 

John, I actually noticed my biggest loss when I put the bigger tires on the truck and I really noticed the loss when I had a heavy trailer behind the truck. If I had kept the truck I would have changed from the 3.73 gears to 4.30 to get some performance back.

 

I know I will lose a bit, but I am hoping the gotts and gryphon could offset that. Would it?

 

And I would consider 18's if that would help.

 

Not really because when you go the bigger tire and wheel combo you are reducing your effective gearing.

 

Nope, not even close. I lost almost 1 1/2 and that is with the Gotts and a tuner. Actually, the tuner did not give me any mpg gains as I tend to drive it more aggressively. I like to feel the power. But, I can feel the power and get the same mpg as I got before. So, my driving habits tend to eat up the savings. Sure is fun too!

 

Morning fellas!

It's so hard to get motivated after a long weekend.

 

you all wanna see something interesting???




http://s128.photobucket.com/albums/p...kerson_749.flv

 

Hey Pam

So do you think I would be better of going with an 18"? I don't want the wheels to look too small on my truck.