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I am the second owner of a gorgeous 2016 Laramie. I bought it with just over 30,000 last August. The original owner put 20" wheels on it almost immediately after he bought it, and he never reset one of the trip meters thereafter. I'll try to post photos showing that in 39,650 miles (out of the 40,478 total on it), the truck has averaged 19.2 MPG at an average 29 MPH. The stats for the most recent 2900 miles are similar: 19.2 MPG at and average 22 MPH. So it's clear that the truck has done more city/low speed traveling than long highway, high-speed miles. The engine hours show 155 hours idling, and 1213 hours driving. Without the idle time, the math says the average speed would have been 33 MPH. The AEM recall was done on the truck just a month or two before I bought it.

I know the 20" wheels throw the mileage off by about 4%, but even adding for that it brings the average MPG to 19.968 - darn close to 20. That's a far cry from the 25, 27, or even 30 I've seen posted on this forum.

I've done very little towing with the truck in the 10,000 miles I've put on it, and I don't think the previous owner did much, if any towing. They used it as a big, comfortable commuter from their home on the beach into town for doctor's appointments and such - about an hour's drive each way on two-lane highway, probably 55 mph speeds. I take it on a 120 mile round-trip on the freeway about once a month. If I'm careful to stay at 70 mph or just under, I can eventually coax it up to 19.8, when I've started out on the trip with an average of around 17. I've never seen the meter read 20 MPG as an average, yet.

Anybody got any ideas?
 

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Have you tried hand calculating the MPG? If I'm not mistaken, MPG is calculated based off the last 200, so having a trip meter with 40k on it isn't really saying anything. What kind of tires are on it? Worse I ever got was 19mpg, towing about 2500 pounds. I had 20s and A/T tires and only took about a 1-2mpg hit, mostly city in the city. Still got 27mpg on the highway(EVIC, not calculated).
 

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Diesels and especially these engines like to be warm, since August most of your driving has been through the cold weather and you've probably been subject to winter blend fuel. That will usually account for about a 2 mpg loss.
 

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Wheel size has nothing to due with fuel economy and since its a laramie it would have those wheels stock. But average speeds of less than 40 mph are city driving not highway so fuel economy wont be great.
 

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There is only one way to know for sure what sort of mileage you are getting and it has nothing to do with tire size or rim size or EVIC numbers or how many nuggets you got in your KFC box at the drive thru'.

1) fill the tank to the first auto stop on the pump
2) start a new trip on your GPS and then go a for a drive for a couple of hundred miles
3) fill the tank to the first auto stop on the pump
4) record the pump volume and the GPS distance and do the math.

Then you'll know. You said the previous owner put 20" rims/tires onto it. Do you know if he had the speedo recalibrated? If he didn't, then your mileage is off and it could be quite a bit depending on what rim/tire size he took off. I went fro 60's to 55's and I am now off by about 5% on my speedo. To do a real 60mph I have to show 63. FCA doesn't have a calibration for 55's on a 20" rim.
 

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Nuts to all those readouts on your EVIC. That fuel mileage is only for the last couple hundred miles anyhow. If it is like mine your reading is a full mpg higher than actual. That would eve be worse.

GPS. Without one what you are considering is probably way off. Watch the speed on the GPS and compare that to the speedometer. Watch the odometer on the GPS and compare that to the odometer in the truck. Use the GPS readings and hand calculate to real results. If you cannot do these things you will never really know.
 

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Your wheels are stock and correct for the vehicle. Tell us about your driving style, if it's Jack Rabbit, then 20 is normal. If it's old grandma, you should be getting at or near 30.

Things to check for: dragging brakes, lose or leaking intercooler hoses, leaking intercooler, boat anchor, travel trailer, etc.
 

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Your wheels are stock and correct for the vehicle. Tell us about your driving style, if it's Jack Rabbit, then 20 is normal. If it's old grandma, you should be getting at or near 30.

Things to check for: dragging brakes, lose or leaking intercooler hoses, leaking intercooler, boat anchor, travel trailer, etc.
I agree, dragging brakes, the front wheel bearings are a know issue, non greased bearings tend to cause friction, drive it for 1/2 hour, coast to a stop and feel the front hubs, heat is an indication of excess friction, a sticking parking brake also, wheel size isn't the issue, outside circumference is all that matters, 33" is stock, bigger or smaller will affect speedometer readouts, my 15 is getting 20mpg after the dealership "fixed" it last year, before the fix I was at 24-26mpg.
 

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For those greasing the front hubs, is the "easy" way to go about it still pulling the wheel, rotor, and ABS sensor then using a grease gun through the ABS sensor port?
 

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There's zero benefit to looking for mileage problems until you are sure you have a mileage problem. Until you quit all the voodoo percentages math and simply go for a measured drive (GPS and Gallons) you won't know. Doing this will also tell you if your speedometer/odometer is accurate or now.

Until you accurately "measure" your mileage you are chasing ghosts.
 

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For those greasing the front hubs, is the "easy" way to go about it still pulling the wheel, rotor, and ABS sensor then using a grease gun through the ABS sensor port?
Yes. A pointed adapter on the grease gun makes it easy. I spin the hub while filling.
 

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If I averaged 22mph I bet I wouldn't even hit 20mpg where I live. I personally don't think there is anything wrong. Next time you go on a non-city trip reset the other trip meter and watch it. Just today because of the virus I noticed that I hadn't gone anywhere except the local stores for a while and my mileage was 17.6.for about 115 miles traveled. This morning I had to drive about a 100mi round trip to the Vet, much of it on high-ish speed country roads, and I reset a trip meter and clocked 30.x on the way up and 27.x on the way back.
 

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How many miles per tank are you getting? The one time I got really lucky, I got 670 miles out of a tank, but would routinely get 550-600, majority highway miles.
 

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YES I got an idea. The government AEM de tune is chit. In the name the EPA and cleaner emissions theory. The old owner cashed his $3,075 check and dumped it on a pass the problem along dealer where it landed on you. Instead of getting an aftermarket tune so that the truck would run better than original & not have the problems of the crappy de tune.

A tune will restore the mileage, power, in fact improve it over original let alone what you are getting in the de tuned state. improve many drive ability features and dramatically minimize the number of future emissions problems & check engine lights etc your truck will have.

Just the basic tune will do. You can also add the EGR cooler delete or get in line to get a warranty paid recall EGR cooler. Not that its of any value once you have an aftermarket tune. In case you didn’t know seems all factory EGR coolers leak eventually. Check your degas tank it should be well above the seam.

Full disclosure an aftermarket tune technically risks what’s left of your warranty. Practically speaking not so much. Regardless Some of us would rather avert problems rather than allow them to manifest to be Band aided by a warranty for “free”. Can I get a truth, 100 percent or amen brother?

I mean you may not like the news and you may not decide to invest in your truck with a tune. But don’t you prefer the truth of where you are at instead of having to try to figure it out over time with more money? With tune & EGR cooler remedied this becomes a pretty great lil truck.


For approximate US prices divide the price by 1.352. So Consider this; Dodge Cummins & Eco Diesel - Eco Diesel Dodge Ram 1500 3.0L 2014-2019
 

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This is getting awfully complicated .....

In his first post the OP said that the previous owner installed 20" rims, but didn't tell us what he took off. Then he tells us about doing math calculations to correct for the 20" rims, which tells me that something other than 20" came off, but we don't know that, because the OP is strangely silent about what came off ....

So .... what was on the truck before the 20" went on? Why all the calc's

If he's doing calc's to compensate for "this and that", it tells me that he has no idea if his EVIC is showing anything correctly, so how can he know what his mileage is .... never mind if it's poor.

Before he starts throwing money at his truck in parts and tunes etc, etc, why not just fill, do a GPS'd drive and refill. After that the math is simple and the result is knowledge ... real factual knowledge.
 

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within the context of affecting mileage
rims / tires will affect mileage based on outside diameter and weight; rim diameter means nothing

a couple reference points (I have a buddy who had the same pickup, he was getting similar numbers)
- A relatively flat 55mph highway with little wind on summer fuel; you should be above 24mpg (I consistently get 26-27mpg on a 600mile round trip, stock rims with BF AT's on a 2015 with 60k miles running 60mph)

- In the winter in town I'm just under 20mpg
 
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