MPGs are horrible

Ok, I installed a 3" leveling kit and 18" wheels with 265/75R18, and since the new lift and wheels my mileage has gone in the crapper. barely getting 300 miles to a tank, when before I was getting closer to 400. I am wondering if maybe I need to have my computer flashed for the bigger wheels and tires? my buddy mentioned that it was programmed with the stock 16" wheels and it is acting like its always towing something?

 

Have you calculated your actual MPH difference-There is a chart somewhere.
It might not be as bad as you think..
MPG will not be as good prior to the change-that is expected.

 

I have not, but I havent gotten a ticket so i am assuming that my mph isnt that far off

 

You put bigger tires on the truck, what do you expect. You added extra rotating weight.

 

I didnt expect to lose almost 100 miles a tank!

 

calculator says it should be off by 2.7 mph at 60. I just figured the 4.0 had more balls than to lose that much gas turning over bigger tires. I would hate to see what it would be if i got a travel trailer behind it.

 

I have 265/70r16, no lift, pipe prerunner bumper, 4 cylinder and I only get at most 280 miles per tank which is about 18 mpg.

 

I just did the metric to inch conversion and you put a substantially larger tire on the truck, your mpgs are gonna drop no matter what. If you didn't want it to change then you shouldn't have put 34 inch tires on it.

 

Our trucks being stock with 265/70/16 or 265/65/17 which equates to about a 31" tire. The difference is almost 3 inches when compared to the 33.6" tire you put on. The weight of the new tire and the size will bring your mpg down, of course. But what you fail to notice is that while you were getting 400 miles per tank before with stock tires, now with the much bigger tire you also have to calculate what your new mpg because the odometer is not reading the distance traveled correctly. I have an ultra guage and when I calibrated it with my 33x10.5x15 tires it tells the percentage difference when comparing the stock to my current tire size. So when I get 230 miles per tank, I then multiply it by 1.122 and that gives me my actual mileage for that tank which would be around 260.

With your tires being bigger I would think that if you multiplied the 300 miles per tank by 1.2 then that would give you a closer number to the actual miles travel'd per tank. I would think even though your odometer reads 300 your probably getting around 350 miles per tank. Which is much more understandable when moving up to a 3" bigger tire.

Hope this wasn't to confusing.

 

^^^^ well said

 

FWIW, I just set the Garmin in a position to compare the oem speedometer to the GPS on a straight road.

My mileage went to crap also. I lost about 50 miles per tank for around town driving. At highway speed of 70 the Scangage is indicating around 15 mpg. While some of this is tire weight, 99.9% is going from stock tires to KM2 mud terrains. Not bitching, just stating that it is a trade off.

PK

 

Since I added my 2.5 inch OME/Dakar setup with Duratracs, I also get 15 mpg @ 70 mph on highway. I tried going at about the speed limit the other day (60 mph ) and was able to get 18.5 mpg on my well calibrated Ultragauge on a 400 mile trip. I don't think I have the patience to go at that speed though...

 

That's what I get stock. Mixed driving with the tach never going over 2500.

 

Again?

6" lift 33" tires bed rack with full size 33" spare and other goodies. 15mpg city 17 mpg hwy. Did you expect it to get better with a lift?

 

Depends on tires too the bigger sizes are always rated for more load and usually are considered LT (light truck) tires they have double the reenforcement kevelar and therefore weigh twice as much per tire if you don't believe it try going to a tire shop pick up a "p" tire and then an LT tire. Huge difference. More weight more power needed to turn em over.