I currently roll on those 31s BFG A/T, and I get about 12l/100km (about 450km/tank).

I want to switch to 33X10.5X15 BFG Km2(should fit after T-bar crank), as I really love Off-roading; but the truck still remains my daily driver, and does a lot of road.
Is my fuel economy going to drop ALOT, or should stay about the same (bigger tires=less RPM for the same speed, which ~should~ compensate for the greater drag of these mud tires)

I'm also planning a 3" BL.... what's the effect on fuel economy again ??

Thanks for your advices guys

 

bigger tires + more height = less mpg's

 

Yeah I guess I can't make an exception on that...
but can I have an estimate, after changing tires..... what can I expect...is it gonna be much worse ?? or just a lil bit.... barely noticeable.

 

every truck and driver is going to be different. If you have 4.10's or 3.73's will make a difference as well

 

I got 4.10(fx4 lvl II); that's why I beleive that bigger tires are'nt gonna hurt it that much, it revs pretty high on highway.
I think my city mpg's going to go up, but Highway is going to stay about the same.

That's also why I chose to buy taller&narrower tires(33X10.5), instead of wider ones (32X12.5).

But I must admit that it's my 1st truck, and don't know what I should expect by doing these mods.... I really love my lil truck, but hate havin to fill it up...

 

It's a truck, did you really buy it for mileage?
If you are concerned about mileage, don't lift it. Period. Especially the body lift (much taller profile).

33x10.50s and a small torsion bar adjustment shouldn't have a HUGE affect, but you will be filling up more often. Taller profile, extra weight, more rolling mass to get rolling, etc. You may lose anywhere from 1-3 mpg most likely. Don't forget to reset the speedometer for different diameter tires.

 

Well you shouldn't have power issues with 4.10's but I would guess a 2-3 mpg hit all around

 

I got a increase when i got bigger tires, but a decrease when i lifted it. so really it stayed the same.

 

You got it! Once I put my SL and 33x12.50s on my city mileage dropped and my highway mileage stayed pretty much exactly the same according to my SGII. On long highway trips it actually got better than I did before the lift/tires. I'm not concerned about the city mileage because I no longer live there!

 

SL with 32's and 3.73's.....i drove like a jerk and got 11mpg. on a good day barely 13mpg

SASed with 35's and 4.88's AND a tuner...driving like a jerk...i get about 15mpg and 18mpg on a good day.

gearing helps ALOT but so does the right driving and equiptment. Im not saying the tuner helped a ton...because if anything it brought me back to driving like a jerk...driving the limit and taking it easy does wonders to your mpg.

in the end we have trucks that already get crap mileage...so its rarely gunna get better. So have fun with it and do what makes you TRULY happy with it.

so buy those tires and get it dirty lol

 

round trip for me to work is almost 70 miles a day... i burn almost a 1/4 tank everyday... I can get 3 round trips out of 3/4 tank that equals to about 225 miles before i get in my uncomfortable zone which is half way between 3/4 and E... If i drive consistant which i never can because of traffic i can squeez 300 miles out of a tank. MAYBE lol

 

Ive seen a few buddies trucks with 4.10 put on 33s and get a mile a gallon or so better just because the rpms drop more, you will be good to go if you have 4.10s but 3.73 will definatly get you less.

 

I have 33x12.50's and a 3" suspension lift and I get almost 20mpg on the highway and about 16.5mpg with the mixed I do all the time. I also have some mods to help that, check out my profile if your interested.

 

Im in the same boat as Mike, Im getting 20ish highway with a 3 inch body lift and 2 inch suspension. All Ive done extra are a dual flowmaster exhaust and a k&n cold air intake

 

Torsion bar cranked with shackles and 33x12.5 wrangler mtr with 4.10 gears... I noticed a mild loss of power but my fuel economy has stayed the same unless I'm wheeling... Then I burn a lot more