Jump to content

Help with gas mileage!

Trevor Myers

By Trevor Myers
in Troubleshooting & Recalls

 Share

Recommended Posts

Trevor Myers Enthusiast

Trevor Myers

Posted
Posted

Alright guys help me out,

 

In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

  • Like 1
14 Silvy Enthusiast

14 Silvy

Posted
Posted

You need to hand calculate it with the bigger tires your computer is showing you traveled less miles due to the larger tires. Also there will be a drop due to the size difference in tires and the rolling mass is increased and the contact patch is larger also.

Sent from my SM-G988U using Tapatalk

Trevor Myers Enthusiast

Trevor Myers

Posted
  • Author
Posted

How do I calculate it? I know i have more rubber and friction and all that. But these tires are actually 3lbs lighter that BF ko2's and all the research ive done I've never heard of anyone losing that much. Also is 22 less rotations per mile alot?

aseibel Senior Enthusiast

aseibel

Posted
Posted

If you didn't recalibrate the speedo, your readings are going to be something like 3-4% too short.

 

So take the old tire's rev/mile and divide by the new one. That will tell you what ratio you need to multiply your mileage by to get accurate readings.

 

That's still not going to improve your mpg number by very much. Raising up the front end & adding wider tires kills your aerodynamics. 

Donstar Senior Enthusiast

Donstar

Posted
Posted

It takes very little to impact the mpg's on our trucks.  They achieve optimal efficiency when stock, unladen and driven gently.  Any changes to these factors and fuel consumption will increase.    Your mpg's, with the changes you've made, sound right based on what I'd expect.  I'm sure your truck looks good and I'd switch out of the mpg screen.  On my last truck I put on larger, heavier tires and took a significant hit at the gas pump.  I simply changed my driving behavior by eliminating an unnecessary trip or two during the week.  It sometimes costs to look good! 

  • Like 2
Eddie 70 Senior Enthusiast

Eddie 70

Posted
Posted

I went from factory 18's to factory 20's and lost 2 mpg. The weight difference was about 20lbs per wheel heavier. Factory wheels and tires.........

Phil Murray Enthusiast

Phil Murray

Posted
Posted
12 hours ago, Trevor Myers said:

Alright guys help me out,

 

In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

⁸

Phil Murray Enthusiast

Phil Murray

Posted
Posted

Part of the answer is -

What was your old worst and overall averages.  You want looks or you want fuel econ?

amxguy1970 Senior Enthusiast

amxguy1970

Posted
Posted
13 hours ago, Trevor Myers said:

Alright guys help me out,

 

In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

Your new tires are approximately 1.1" taller so that is 3.5% larger which means you need to multiply your current mileage 1.035 (that is 3.5%). So your 15.4 mpg is really 15.9 mpg. As others have noted, your tires are heavier (stock were P-rated and your new tires appear to be LT rated), they are wider, taller and your truck is taller with the nose more up as opposed to having some aerodynamic rake. All that can certainly add up to nearly 4 mpg at highway speeds, that is a bunch going against the factory aerodynamics and weights. Did you also remove your air dam or do anything to it? Not much you can do but make sure the tires are inflated properly, make sure the air dam is on, maybe add a rear block to angle the nose down a hair for better aero (not lowering it) or lowering the truck a little, 2.5" is awfully larger and will add wear and tear on the front of your truck along with the heavier and larger tires. Gotta pay to play, I understood that when doing my truck so I added a 1.5" level, P-rated tires 1 inch larger but stock width and only trimmed the air dam instead of removing it, I lost between 1-1.5 mpg over stock. 

 

Tyler

Bash74 Enthusiast

Bash74

Posted
Posted

Some people say when they switch to winter blend gas the milage goes down. Are you on a winter blend now.

Sent from my SM-G975U1 using Tapatalk

  • Like 1
TXGREEK Senior Enthusiast

TXGREEK

Posted
Posted
Alright guys help me out,
 
In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

Tires, it’s your tires. Add air, get a tuner (SuperChips), switch back to stock air filter and go from there.


Sent from my iPhone using Tapatalk
aseibel Senior Enthusiast

aseibel

Posted
Posted
31 minutes ago, Bash74 said:

Some people say when they switch to winter blend gas the milage goes down. Are you on a winter blend now.

The OP is from the other side of the state from me. We are definitely on winter blend now. I kind of ignore the fuel economy numbers from October to April and focus on the summer months, haha.

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
2 hours ago, Bash74 said:

Some people say when they switch to winter blend gas the milage goes down. Are you on a winter blend now.

Sent from my SM-G975U1 using Tapatalk
 

Since September 15 we all have been. I post the following about twice a year at each change when this topic comes up: 

 

The difference between summer- and winter-blend gasoline involves the Reid Vapor Pressure (RVP) of the fuel. ... The US Environmental Protection Agency (EPA) says conventional summer-blend gasoline contains 1.7 percent more energy than winter-blend gas, which is one reason why gas mileage is slightly better in the summer.

 

Winter gas accounts for a MAXIMUM of 1.7% of the mpg loss. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.3k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,739
    Total Members
    8,960
    Most Online
    chfkief
    Newest Member
    chfkief
    Joined

  • Who's Online   4 Members, 0 Anonymous, 1,508 Guests (See full list)

  • Latest Articles

  • Posts

    • Chuck FB
      Joke Thread

      By Chuck FB · Posted

      Fred was in the fertilized egg business. He had several hundred young pullets, and ten roosters to fertilize the eggs He kept records, and any rooster not performing went into the soup pot and was replaced. This took a lot of time, so he bought some tiny bells and attached them to his roosters. Each bell had a different tone, so he could tell from a distance, which rooster was performing. Now, he could sit on the porch and fill out an efficiency report by just listening to the bells. Fred's favourite rooster, old Butch, was a very fine specimen, but this morning he noticed old Butch's bell hadn't rung at all! When he went to investigate, he saw the other roosters were busy chasing pullets, bells-a-ringing, but the pullets, hearing the roosters coming, would run for cover. To Fred's amazement, old Butch had his bell in his beak, so it couldn't ring. He'd sneak up on a pullet, do his job and walk on to the next one. Fred was so proud of old Butch, he entered him in the City Show and he became an overnight sensation among the judges. The result was the judges not only awarded old Butch the "No Bell Piece Prize," but they also awarded him the "Pulletsurprise" as well. Clearly old Butch was a politician in the making. Who else but a politician could figure out how to win two of the most coveted awards on our planet by being the best at sneaking up on the unsuspecting populace and screwing them when they weren't paying attention. Vote carefully in the next election, you can't always hear the bells.
    • chfkief
      FS: Black Bear Performance AutoCal Tuning System

      By chfkief · Posted

      Do you still have?
    • 3CarSeatDad
      High Country Suburban build confirmation

      By 3CarSeatDad · Posted

      Can someone confirm if the GM order workbench terminal is able to validate a custom build sequence:   1) Initialize the Allocation Base: Open a new vehicle build queue, select the 2026 Chevrolet Suburban 4WD, and pick the High Country (3LZ Preferred Equipment Group).   2) Select the Diesel Powertrain: Go directly to the engine configuration screen and choose RPO code LZ0 (3.0L Duramax Turbo-Diesel). Ensure it maps to the MHS 10-speed automatic transmission.   3) Deploy the Seating Swap: Navigate to the Interior Options screen and enter RPO code ATT to replace the standard captain's chairs with the power-release 60/40 bench seat. Because you are not trying to force a separate luxury or air-suspension bundle, the standard, premium D07 Fixed Floor Console remains active. The system will accept this change immediately without triggering a warning message.   3)Apply Heavy-Duty Hauling Capability: Input RPO code NHT (Max Trailering Package). The commercial terminal will automatically bundle the required trailering hardware and software modules to support the diesel engine's maximum towing capacity.   5) Layer the Premium Tech and Glass: Separately add code C3U (Panoramic Power Sunroof) and code UKL (Super Cruise) to the order screen.   6) Run the Final Validation: Click the "Validate Order" button at the bottom of the interface.
    • revmanii
      Looking at ordering a '26 WT because I want a std cab, std bed

      By revmanii · Posted

      Spent the last hour or 2 googling and reading up on the spacer thing. I don't like the loss of thread contact on the slip on spacers, but it appears you can get "extended" lug nuts that reach into the hole of the wheel to get back the lost threads. Looks like the only true hubcentric slip on spacers are at least .375". I'd want as little as I could get away with and don't want to cause other clearance issues going any thicker. Bora seems to offer what appears to be a well made .375" spacer and extended lug nuts. I searched here and did find a couple threads recommending Bora. But not cheap. By the time I buy spacers and lugs, new TPMS sensors, then pay a tire shop to install the new sensors, I suspect I'm going to be in over $400. Thinking about running out and getting some washers to put behind the wheel to see if .375" is enough to clear calipers, turn lock to lock without rubbing, and to see if the wheels/tires look strange pushed out a little. This would just be to check fitment.
    • Core-Lokt
      Road Master Active Suspension

      By Core-Lokt · Posted

      Roadmaster makes some quality parts; I have their sway bar. I considered the RAS, but I ended up bagging. I didn't know what kind of ride I'd get with RAS, and the bags have interior jounce bumpers, so I can run 0 pounds pressure. I figured I'd have the best of normal suspension ride with assist on-demand. But it seems you got pretty much the same in one item.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...