MPG decrease with 37s?

Stokt · Jun 9, 2016

I apologize as I am sure this has been discussed, but I have searched and can't find it.

I'm currently running 35x12.50s with stock suspension and I'm averaging 18.5 mpg hand calculated, which is mostly highway. I have 3.55 gears.

How much should I expect my mpg to decrease going to a 4" to 4.5" inch lift and 37x12.50s? If it matters, my other mods are in my sig.

I really prefer the look of this set-up, but if it's going to kill my mpgs, I may go with a 2.5" lift and stick with 35s.

sootie · Jun 9, 2016

you will easily kill 2 mpg maybe more.

TripleE44 · Jun 9, 2016

I never hand calculate, but when I went from 35s on 20x10s to my 37s on 17x8.5 I went from 17.9 down to 15.9 according to the dash. Same 3.5" lift on both

FX44AU · Jun 9, 2016

I went from 295/65/20 AT2s on 20x10s to 37/12.50/20 Trail Grapplers on 20" Platinum wheels and lost about 2.5 mpg. No change in ride height (3" with both).

Stokt · Jun 10, 2016

Yeah my guess was about 2 mpg. I just have to decide if it's worth it. Thanks for the replies.

FX44AU · Jun 10, 2016

Looks good but I'll be going back to lighter 35" tires when these wear out.

Stokt · Jun 11, 2016

That's exactly my fear. I don't want to go with a bigger lift and tires and end up regretting it. I know a lot of people run 35s with a 4" lift but I can't decide if I like that or not. I see some trucks that look good to me and some that look like the tires are too small. I can't figure out the difference. Maybe it's the wheel offset. Idk.

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TripleE44 · Jun 11, 2016

If I wouldnt have went down to a 17" wheel, I probably would've went back to a 35 when my 37s wear out. They really don't make that much of a difference. But it would look weird with a 17x8.5 on a 35 with the 3.5" lift. The 20x10 with 35s never looked small, but I could see where a 9" wide would.

Laynrocker84 · Aug 29, 2016

Fx44au, why are you going back to 35's? I was planning on doing the same lift you have but with 37" rt's. Any suggestions?

Thanks
Trey

Stokt · Aug 29, 2016

I didn't think to ask this before, but did your drops in mpg take into account that your odometer is off with the bigger tires? I'm getting closer to having the money saved for a lift and I can not make up my mind on what I want to do.

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PowerStrokePops · Aug 31, 2016

Stokt said:
I didn't think to ask this before, but did your drops in mpg take into account that your odometer is off with the bigger tires

I've got one of the speedo calibraters on my truck with 37's with 8" lift. Lie-o-meter will stay around 15.6 if I drive like a grown azz adult. Haven't hand calculated in awhile. Speedo is pretty accurate.
Full emissions on tuning.

PowerStrokePops · Aug 31, 2016

PowerStrokePops said:
I've got one of the speedo calibraters on my truck with 37's with 8" lift. Lie-o-meter will stay around 15.6 average in the Houston area if I drive like a grown azz adult. Haven't hand calculated in awhile. Speedo is pretty accurate.
Full emissions on tuning.

That is in a 2011 ccsb.