MPG Discussion: Factors That Impact Your MPG

I've seen a lot of discussion related to MPGs for our trucks and wanted to start a discussion about what impacts the MPG that you get. There are a lot of factors that go into it; very rarely are two people's situations considered equal. Here are some thoughts on what can impact the MPGs you are getting with your 3rd gen:

• Tire size & type
• Tire rolling resistance rating
• Tire pressure
• Accessories/mods that affect the truck’s aerodynamics (roof racks, cargo boxes, etc)
• Road conditions (snow, paved/unpaved, etc)
• Road elevation changes
• Driving style (aggressive aka mashing the skinny pedal all the time, old timer aka never going above 2k RPMs, etc)
• Idling time
• Driving at high speeds (highway MPG ratings are typically done at 55 MPH on flat roads)
• Outside temperature (vehicles are less efficient at colder temps)
• Running electrical accessories (running A/C on max can decrease MPG from 5-25%)
• Drafting other vehicles (particularly semi-trucks)
• Fuel blend (winter vs summer)
• Ethanol content of the fuel
• Weight in the vehicle (driver weight, passengers, loads in the bed, etc)
• Head wind vs tail wind
• Brake drag if present
• Tailgate up or down

Am I missing anything? If you are complaining about MPGs, it's worth assessing your situation and identifying if you are doing anything that could be causing a decrease.

For those of you who say "rabble rabble you bought a truck if you care about MPGs buy a Prius", move along. I'm sure if you bought a mod/accessory that didn't do what it claimed, you'd want an explanation too (for example - if you buy a battery with a 3 year warranty and it dies after 2 years, you'd be annoyed. if you paid for a 3" lift but only got 1.5", you'd be pissed. etc).

 

You may have missed one of the BIGGEST detriments to aerodynamics: Lifting.
Also, keep yer truck serviced. Air filter, clean, etc.

 

Driving above 2k rpm

 

Ice accumulation....my truck must have picked up a few pounds after this weekend

 

Tire and rim weight makes a huge difference.

 

Yes - i would consider lifting under the 4th bullet - accessories/mods that impact the truck's aerodynamics. Clean air filter is definitely one I should add.

 

Yep - I mention this in the 7th bullet

 

Yes, definitely. This is a good one to add.

 

Some of those big girls I pickup at LAST CALL can affect my gas mileage. Think my taco is trying to warn me not to do it but my other head is saying, Do it! Fucking do it!

 

LOL they definitely can! I'd file this one under:

• Weight in the vehicle (driver weight, passengers, loads in the bed, etc)

 

Put the beer goggles down.
Or, make them ride in the back, if the roads are icy.

 

Elevation will make some difference. Maybe not anything drastic, but some.

 

Your list looks comprehensive. This is a good reminder and reference.

You might want to specify cap/tonneau in bullet 4. I think my millage actually got better after I got my cap.

 

tonneau cover and front air dam

edit: I guess these fall under bullet #4.

 

Thanks for pulling this together. I just purchased a Limited 2017 about 5 months ago, and had it lifted, along with TRD wheels and tire setup. Get no where near what i read on this forum... like 13 in the city, maybe 17 on the HW if I drive super easy. Assume that's pretty normal in my case?

Luckily my commute is about 5 miles

 

For bullet #6, here is a handy site that lets you map the elevation change for your route: https://www.doogal.co.uk/routeelevation.php

I used it to map my morning commute and it's clear why I get better gas mileage traveling to work than traveling home, especially when combined with bullet #16 where I often have a tailwind in the morning and headwind in the evening.

 

I definitely second the wheel and tire weight. I just recently changed from a MT to AT and changed rims. So between tread pattern and 12 lbs per wheel lighter i am getting 3.25 more mpg.

 

I've always done the same thing, especially when I first buy a car/truck. The first six months are spent trying to optimize gas millage by experimenting with different speeds and driving habits. Invariably after owning a vehicle for a time, I've proceeded with mods that hurt gas millage. But at least I'm making informed changes, I guess.

 

- ETC
- Windows down/ back window open
- Low transmission fluid level (slip)
- Drive shaft lubed
- Wheel alignment (probably under rolling resistance)
- Air damn/ splash guards

 

10lbs of rotation weight, 2.5lbs per wheel, saved is roughly 100lbs off the chassis. My '85 Chevy's steel 8 lug 1-ton rim is 22lbs heavier than the aftermarket alloy rim! 88lbs of rotational/suspended/braking weight removed.