ok in that case where do i need to get gears from

 

and what do i need to buy

 

When calculating gas mileage, have you taken into account the final drive ratio that has now changed due to gas mileage? You may actually be getting better gas mileage than you think because of this. Your truck is showing a certain percentage lower miles to the tank than you are calculating.

 

you might need to have the comp reset for the tires from the stock size to
the 33's i know when i put 35's on my 95 i had to i pick-up 5miles to the gal

 

ya know i havent thought about that, and it makes perfect scence, duuuuuuuhhhhh on me

 

First of all, if you are not calculating your mileage with the new tires, you are definitely not getting 12 mpg.

And don't do ANYTHING to the computer. That would be a complete waste of money. We are talking 3rd grade math here. Write the number in your gas book, and multiply on the calculator at the pump. Literally one extra step. Takes 2 seconds.

 

Well, now, wait a minute here ... his speedo COULD be MORE accurate with the larger tires - mine was!

BUT to compare before/after, you definitely need to calculate the tire size difference in.

 

How's unplugging the battery to reset the ECU a waste of money? Sometimes you guys slay me.

 

Wasn't referring to your post, but rather what I took from this post

Your post made perfect sense, and is not a waste of money. But to me "having" the computer reset for 33's meant take it somewhere and have the speed sensor stuff redone to be accurate for 33's.

I should have clarified, don't pay to have the electronics redone for bigger tires.

 

Ah, sorry. My confusion.

 

I am running 4.56 on my 2.7 with 32's and during the summer i get around 22-23mpg, right now with alot of wind a huge elevation change and winter gas i am getting around 16-18mpg

 

what calculator are you talkin about? and how do i figure out how off my odo is?

 

Take your current tire diameter (measured with a tape) and divide by stock tire size (again, measured with a tape). Then multiply by the mileage you think you're getting.

eg:

32.5" / 28.3" * 12.9 mpg = 14.8 mpg which is in the 'acceptable' range due to leadfootitis at high freeway speeds.

Also, slow down a bit. Using the above tire sizes, at 75mph (indicated) you're actually going 87mph!!!! So to go 75mph actual you should be driving at 65mph (indicated). Fuel economy at 75mph is much better than 87mph due to wind loading (aerodynamics).

 

wow thats bad I got 312 miles on my 16 gal. tank with my old 33x12.5 but Im running my stock 4.56:1 gears

 

There you go. The only calculator you need is a 5 dollar one from the store. Keep it in the glove box with your mileage book.

If you regear, you also throw that ratio in there. I figured mine out, wrote down the first two digits in my book, which are 0.97. Every tank, I multiply my mileage by .97 to get my true mileage.

Easy.

 

When i bought new tires my mileage dropped a few mpg's. but the new tires a super aggressive and weigh more. tread pattern and width makes for more rolling resistance and more weight, well you get the point.

Looking for some cheap 33x9.5/10.5x15, anybody? for pavement pounders.

Will say I love the off road performance and regearing helped.

 

What gears do you have right now? Im running 33x1250x15 with factory 4.10's and the 3.4L and i get wayyy better than 12mpg. Hell i fried my ring and pinion a few weeks ago and i just picked up a yukon 4.10 rebuild kit for it, i was considering regearing both ends to 4.88's but frankly the 4.10's do just fine.

 

NOTE: These calculations are ONLY valuable for COMPARING against what your MPG are before the mods. There is no need to do them every time!

The reason I say this, is because in my experience, our speedos are off SIGNIFICANTLY from the factory. The ONLY way to know is either time over distance or compared to GPS.

Also, the odometer is the backup to the gas gauge - you need to be aware of how many miles you get per tank on the odometer, whether it is actual mileage or not ...

 

cool thanks guys, yall have helped me alot