Lift = how much MPG drop?

[JBakerFX4]

This is a very wide open question, but what kind of MPG drops are people seeing, with say a 4" lift and stock 20's and tires? I took a hwy trip today. 200 miles round trip. On the way out... averaging 17-18 mpg doing about 70. On the way home, at night, droped the speed down to 63-67 and got 19-22 mpg. I've got 5,000 miles on the truck, but have had 2 oil changes so far. Wondering if my MPG should get better with milage like the owner's manual says... "after 10K miles". and, supposed to be going to a 35x12.50 Procomp Xtreme AT on the factory 20's. Wondering how bad that is going to hurt my MPG's.

[stump0331]

i doubt a lift alone will affect mpg

its the bigger tire size that is whats gonna get ya

[03f250stroke]

I have 35s and with my mods I get about 15 tops around town

[95BLKLSC]

I have a 6 inch lift and 37's and I'm getting 15-16 on average with about 80% highway. I also have a bully dog chip, AFE intake, and exhaust. I still have the stock 3.73 gears though. I'm sure without the lift and large tires the truck would see about 20. So yes I think it is a signifigant drop in mileage. And the lift MUST effect mileage, your cross section alrea is now larger, which creates significantly more drag especially at 65+ MPH. Is it worth it, HELL YES!! Although I'm not commuting everyday with this truck. It's used once a week if that.

[Lone Ranger]

Stumpy is right.... Lift does not come into it..

But tyre size does. Also: The more aggressive the tread the more the growl, the more the drag... The more height and weight the more torque it takes to get it started... However there is an upside to it on the highway. The PSD has heaps more torque than it needs to run down the highway, and the taller tyre size gives you 5% more speed per RPM... My 7.3 Effie got 5% nearly, going to 285 BFG tyres, in other words was going 100 kms per hour but ready 95 k/p/h on the speedo. If you factor that in your fuel economy figures you come up with a plus... And, these 6.0s seem to get better fuel economy when you stay under 2000 rpm. So taller tyres means 5% faster than what you are reading and that is 5% less rpm to go the same speed.

On mine it worked out to be about a 5% better fuel economy as well.. Then that all goes out the window when I switched to a more agressive tread on my old F-250 and went BF Goodrich Mud Terrain. It end up back at about where it started. But did it throw mud around nice...

Regard from the Ranger in Oz...

[JBakerFX4]

Well, I'm looking at At's, that weight approx 10# more than the stock tires. I have seen some members on here running 35x12.50's one aftermarket wider wheels, with just level kits!

[kinghawg98]

so if one puts "weenie" tires on the lifted truck you should get better mileage?

i got some beefy mudding tires....but probably wont drive them on the upcoming 2800 mile trip......so....thinner 35" tires would perhaps safe mileage with the previous theory?

[eazenutz33]

my rpms are lower at roughly the same speeds after going from 30.5" tall tires to 34"+ tall tires. Taking off I'm sure its gonna hurt me a bit, but on the highway it seems like the rpms drop significantly.

I would think a lift WOULD make things harder on your truck...you're raising the body higher, typically leveling it out reducing the nose down look....all which should allow more air under the truck and putting more "face" into the wind. My truck is leveled and I would think even that would cause a small drop in mpg.

[JBakerFX4]

... well, lets put it this way. truck came stock with 34.1" tall tires. I don't want to go shorter than OEM. What I really "need" in a tire is for it to be "W I D E R" than the stock pizza cutters. I like to camp and trail ride in sandy areas. so going 1 size up than stock is say... 35" height. so screw it. 35x12.50's on the stock 20x8.5's. And I'd prefer the truck to be as LOW as possible to fit those tires w/out rubbing; cutting the front valance is not an issue. Diesel is $3.50/gal and i'm feeling it. will be driving 340 miles/week just for work. so I'm kind of froze at what really do here.