mpg

[dangerranger01NJ]

I was just wondering if anybody has ever researched it and tested it but what do you guys think would be the most economical speed to drive to get maximum fuel economy with a 4.0single overhead and 32 s with 410 gears so far after putting the 32's on I have been getting roughly around 17 to 18 mpg I usually keep it between 50 and 60 I try to stay off of the freeways especially with four tens

[Mike In Bama]

Your best milage will always be at the lowest speed you can shift into your highest gear.

[dangerranger01NJ]

Ohh so around 45-50 makes sense

[pcityranger]

4.10 and 32's bring you close to a 3.73 if that makes sense, so freeway shouldn't hurt you. These things aren't meant to cruise above 70 anyway.

How ever I have 32's and have noticed a slight difference in power. Really only notice it in third gear, not sure why but that gear feels sluggish than the rest. I have to get a tad higher rpms when shifting now because of the size difference. I also have a manual, you never stated your trans.

[dangerranger01NJ]

I have the 5r55e auto. Its actually getting flushed tomorrow since I have off work. And as for the gear ratio that makes total sense. And your right about the 70 mph on the highways if im doin70 im usually at 2700-3000 rpms

[pcityranger]

70 mph on the highways if im doin70 im usually at 2700-3000 rpms

That sounds kind of high, I have 4.10s as well and I haven't recalibrated my speedo, but doing the supposed "70" on the highway, I think I'm around 2500, at 80 I'm at 3k.

I wonder sometimes how off my speedo is because of the 32's.

[RoberticusMaximus]

i've got 4.10s & i'm close to 3k at 70 iirc. my needle could be off though lol
edit: with 225/70/15 tires (stock but a little smaller than other models)

[dangerranger01NJ]

Originally Posted by pcityranger

That sounds kind of high, I have 4.10s as well and I haven't recalibrated my speedo, but doing the supposed "70" on the highway, I think I'm around 2500, at 80 I'm at 3k.

I wonder sometimes how off my speedo is because of the 32's.

Yea 70 at 2500 sounds more like it. I dont really pay that much attention and when i put the 3 inch kit on mine (New keys and an AAL) I also got 265/75r16 Cooper at3 tires and I think my speedo is off only by like 1-3 mph.

[pcityranger]

is your truck 4x4? Sounds like your getting pretty good gas mileage.

[dangerranger01NJ]

Yea its an 06 fx4 I get roughly around 15-18 going back and forth to work and the girlfriends house. If i ran it empty I estimate 315 miles to a tank

[Cole_CT]

I'm getting 13 on my Fx4 with 31s...mostly city though.

[pcityranger]

I get about 14-15 city with the 32's. Haven't done much highway driving to give an exact.

[dangerranger01NJ]

Yea I rarely hit the highways, esp in Jersey lol

[bjurke]

i was told 40mph and every 10mph increase will cost you 10 percent. if you accelerate hard the effect is even worse. i get 25-30mpg on the highway but i use canadian gas which is 20 percent more volume and i am using original tires with a 3.55 gear ratio and i do not have 4 wheel drive.

[johnday]

You guys need to go here, http://www.agcoauto.com/content/plug...peed/calc.html, and figure out the difference from your stock size. It won't give you the RPM's, but will show how much the speedo is off.
I have a 9.6% difference between 235/75/15 and the 265/75/16 I have on now. While driving, I round it off to 10% just for ease of calculating, and add 1/2 mph +/-. So, at 55 mph indicated, I'm right about 60.5mph +/-.
Then figure your fuel mileage as normal. Don't forget to add the percentage to either the miles driven, or the mileage after figuring it out.
So, in my case, let's say, 350 miles, divided by 18.57 gallons, plus 9.6%, gives you, 20.66 MPG. That's just an example, plug your own numbers in once you find the percent difference.
Didn't answer the OP's question, just thought I'd throw that in here.
BTW, I've tried to get that calculator on here as a sticky, but seems the admin doesn't think it a good idea.