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MPG loss with large tires

Penguin VII

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Penguin VII Enthusiast

Penguin VII

Posted
Posted

So I've seen some discussions here related to this but the answers seem to swing wildly from one extreme to the other.

 

I'm going to lift and throw some larger tires on my new beast. My question is if anyone has seen some sort of MPG calculator, or if there is info online I can use as research to help my decision here.

 

I want a 4-6" lift with 35s. I'm curious to hear what I can expect to see in MPG after this. I'm getting pretty solid for the first few hundred miles I've driven it, and I didn't buy a truck for the MPG, but also it's my only vehicle and I don't want to be in single digit MPGs.

 

So does anyone have any calculator or math I can use to estimate my MPG loss?

TxTruckMan Senior Enthusiast

TxTruckMan

Posted
Posted

Take the height of your lift, add it to the delta height of your tires from stock (32"), and then divide by 2. That is the average amount of MPGs you can expect to lose.

 

(6" lift + 35" tires)/2 = ~4.5 mpg drop.

(4" lift + 33" tires)/2 = ~2.5 mpg drop.

 

I just made that up, but it's probably not that far off. YMMV - drastically.

Condon1 15 GMC Enthusiast

Condon1 15 GMC

Posted
Posted

Take the height of your lift, add it to the delta height of your tires from stock (32"), and then divide by 2. That is the average amount of MPGs you can expect to lose.

 

(6" lift + 35" tires)/2 = ~4.5 mpg drop.

(4" lift + 33" tires)/2 = ~2.5 mpg drop.

 

I just made that up, but it's probably not that far off. YMMV - drastically.

 

Hey its close, after my 6" lift and 35s i lost about 4 MPG

Cowboyman Enthusiast

Cowboyman

Posted
Posted

Unfortunately it is true....On my 2007 I could get 20MPG around town, when I was trying hard....I put on some bigger BFG All Terrains.....never got above 18 around town again.

 

 

The bigger tires are a lot heavier and that hurts it too.

Penguin VII Enthusiast

Penguin VII

Posted
  • Author
Posted

Take the height of your lift, add it to the delta height of your tires from stock (32"), and then divide by 2. That is the average amount of MPGs you can expect to lose.

 

(6" lift + 35" tires)/2 = ~4.5 mpg drop.

(4" lift + 33" tires)/2 = ~2.5 mpg drop.

 

I just made that up, but it's probably not that far off. YMMV - drastically.

Haha, well thanks for making up math for this.

 

I'm good with a loss of 4-5MPG, you gotta pay to play and all that, but from reading some info here and other forums I'm seeing some people talk about going from 19-21MPG to 11-12. That's a pretty steep drop.

Condon1 15 GMC Enthusiast

Condon1 15 GMC

Posted
Posted

Haha, well thanks for making up math for this.

 

I'm good with a loss of 4-5MPG, you gotta pay to play and all that, but from reading some info here and other forums I'm seeing some people talk about going from 19-21MPG to 11-12. That's a pretty steep drop.

The only time ive been able to get "good" MPGs was on the free way where it was nice and flat than i might get 19-20 MPG

pcruis1 Enthusiast

pcruis1

Posted
Posted

I've lost 2 mpg overall with 4 inch bds and 33x12.5, and that's with a post lift custom tune. 50 mile best stock was 29 mpg. 50 Mile best post lift and tires is 22 mpg.

ifixedit Enthusiast

ifixedit

Posted
Posted

I sell commercial truck tires for a living, it's fairly simple. The larger the tires the more mass and weight you are pushing down the road, hence the poorer fuel economy. Rolling resistance is also a factor, some tires are better and some are worse. If you look at today's large trucks as an example, a majority of them and large fleets in particular have all gone to smaller wheel size (22.5" vs. 24.5") and low profile tires, saves weight and fuel.

TJay74 Senior Enthusiast

TJay74

Posted
Posted

The problem is that most lifts use bigger tires and the speedo is never recalculated to be accurate. So if you are going off of the miles driver per the odometer you are off. Only way to calculate accurately would be to use GPS to measure distance and drive a set route with a known distance from a full tank and then top off and hand calculate or else get the speed re-calibrated which requires custom tuning of the ECM and potentially brings up having the warranty invalidated if you go in for warranty work depending on the type of work.

ifixedit Enthusiast

ifixedit

Posted
Posted

Yes, when making a wheel / tire size change you have to recalibrate the speedo. You have to know how many revolutions per mile the tires turn, this at least applies to large trucks and I'm sure is the same for a Chevy pickup. One other issue with going to larger tires / wheels is it potentially puts the truck out of it's optimal power band which without a gear change to a lower ratio can also kill fuel economy.

Penguin VII Enthusiast

Penguin VII

Posted
  • Author
Posted

I'm all good with swaping gears if needed down the road. Potentially right after I get the lift/tires if its needed. I also know about needing to get the speedo recalibrated. That said, my jeep wrangler was supposed to get 18/22 from the factory. I never got over 17 on the highway, ever. I went from whatever was stock on the x (no idea, it was quite a few years back) to 35s and never got over 14.

 

The engine on that thing was woefully underpowered even in stock form and throwing much heavier larger more aggressive tread tires on it didn't do me any favors. That said the V8 on this truck seems to handle pretty well and I would assume that it will handle the extra rolling weight much better.

 

Just trying to get a rough idea here as I've heard everything from 1-2 MPG drop to seeing 8MPG. Seems like a serious difference.

Havvkeye Enthusiast

Havvkeye

Posted
Posted

With my lead foot I couldn't seem to get over 18 or so pre tires... still getting over 17 with my 33" and a 2" level.

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