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In our effort to keep things concise, all posts concerning fuel mileage will be posted here. I apologize for the elimination of the other thread; it is archived for your reference (combined with steering wheel peeling thread).

To summarize what many of us have discovered in our discussions on fuel mileage:

Fuel mileage is a common complaint on this subforum, and can vary depending upon geographical location, outside temperature, wind speed, elevation changes, personal driving habits, type of road, etc. Many members claim that fuel quality also affects mpg.

The 40-mpg claim is a projection for freeway driving. Your overall tank average is that of all your driving, so unless you only drive gently on perfectly flat freeway, it will be HIGHLY unlikely that you will get a combined tank average of 40 mpg.

The read-out on your dashboard may not reflect perfect accuracy, so it is recommended that you still manually calculate your own fuel mileage if you prefer a more accurate readout.

Most of you seasoned members already know this, but for anyone new to the Elantra and/or to the forum, please post all your questions here before starting a new thread on the topic. Thanks a bunch! :D
 

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I'd encourage those closely tracking fuel mileage to create an account on fuelly.com and to enter the data for their driving. This is a great resource to keep track of your own mileage and to compare to others. It's free and easy to use.

- Mark
 

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One other point to add to any fuel economy thread - Hyundai odometers read "low", not recording all the miles you drive. So if you prefer the "hand calculated method" of dividing miles on your trip odometer by gallons counted on the pump, be aware that the displayed "miles" is too low, and that means your calculated mpg will be lower than actual. In the Elantra, only 96.6 miles out of every 100 driven are being counted, although that number varies slightly based on which tire/wheel combo you have on your Elantra.

If you don't want to fuss with correcting the pessimistic odometer, just take your hand calculated mpg and multiply it by 1.035 to get the corrected mpg.

Example:
309 miles shown on Trip "A" is actually 319.8 miles.
The pump says 8.0 gallons added.
Hand calculated: Trip "A" divided by gallons added = 309 / 8, or 38.625mpg
Corrected: (Trip "A" x 1.035) / 8 = 39.977

Alternate: 309 / 8 = 38.625 - hand calculated mpg. And then correct it - 38.625 x 1.035 is 39.977
 

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Wow! :eek: Thanks dmlexpert, never knew! So does that mean that our cars actually have more miles on them than they say they do? Rather bothersome, IMO...
 

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Yes, actually. Your 100,000 mile powertrain warranty lasts an actual 103,500 miles. :) When correcting the distance, the dashboard mpg meter is actually closer than people realize. It's still not on target, and it can be thrown off by wild variations in city/highway driving mix, but it is closer than you think.
 

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IMG_20120725_221525.jpg Taken a couple of weeks ago... Over the course of six days, mostly highway miles obviously. But still, I'm happy with my mileage :p This is no fluke, either, as my display currently reads 44.2 mpg avg. after 1/2 tank of fuel. It's been around 40 avg. all summer for me! Admittedly though, my grandpa thinks I drive like a grandpa... haha
 

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One other point to add to any fuel economy thread - Hyundai odometers read "low", not recording all the miles you drive.
What is your source for this?

Most odometers are fairly accurate to within +/- 2% or so. They have to be because vehicle certification regulations require it. I'd be surprised if Hyundais are any different, especially since it would lengthen their warranties and under-estimate their gas mileage.

- Mark
 

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The few times I calculated by hand, my MPG numbers came out to within a tenth of what the trip computer was telling me, so now I'm content to go with its figures.

I've put 11,000 miles on my 2012 Elantra GLS Preferred since I bought it last October, and currently I'm getting between 30-33 combined MPG and 37-38 MPG on the highway, in hundred-degree Midwestern heat and with MAX-A/C running almost constantly. Which I'd say is pretty good. No complaints here about my mileage.

With decent (ethanol-free) gas in the tank and cooler spring temperatures, I've hit the magical forty MPG mark in spirited highway driving. OTOH, last winter, between letting the car idle to warm up and slow driving on slick roads, I had a couple of tankfuls where I averaged 25-26 mpg.

Like they say: Your mileage may vary.

There's a guy on another forum who's been kidding me about my Elantra's "inflated" mileage figures. He has a Prius and a new 2012 Ford Focus, and drives the Ford when he feels like taking a spin in an actual car and not an appliance. He claims an average of 33 mpg with the Focus.

He's also had to take the Focus back to the dealership within the first couple of months he's owned it, with a suspension problem. Something about the front struts and springs needing replacement.

And meanwhile my little black raven just keeps chugging along... :harhar:
 

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Admittedly though, my grandpa thinks I drive like a grandpa... haha
I'm a grandpa, what's wrong with that? 

I have no complaints with my mileage. Not only do I get great mileage, IMO, but I get it driving around town "in style!" 
 

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I'm a grandpa, what's wrong with that? 
:D hahaha absolutely nothing, I just wanted to make it clear that I do have to "work" to get the kind of mileage I get... although, a majority of my summer driving is done @ 60 mph with the A/C on and/or windows open (yes, both haha), so it could be even better yet. Speaking of that, has anyone noticed a huge difference in mpg with the A/C on or windows open? It only seems to hurt my mileage by 1 or maybe 2 mpg... pretty insignificant and certainly not worth sweating over IMO.
 

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What is your source for this?

Most odometers are fairly accurate to within +/- 2% or so. They have to be because vehicle certification regulations require it. I'd be surprised if Hyundais are any different, especially since it would lengthen their warranties and under-estimate their gas mileage.

- Mark
Source - dozens of calibration drives, with the results duplicated over and over again. Anyone with a GPS, access to Google Maps, or a highway with mile markers and prove it on their own. Those who do not wish to correct their odometer count can use the Trip A/B as is since doing so is otherwise harmless. It gives you lower mpg numbers but the warranty lasts longer. I kinda like it that way.

The regulations prohibit odometers from being overclocked. GM and Honda ran into trouble in the past by overclocking the odometer. There is no rule regarding underclocking, at least within 5%, as far as I know. The only way to run into a problem with the law is if you rig the odometer to read far lower than actual mileage. An OEM underclock is no problem.
 

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Source - dozens of calibration drives, with the results duplicated over and over again. Anyone with a GPS, access to Google Maps, or a highway with mile markers and prove it on their own.
So you concluded "Hyundai odometers read low" with a sample size of one car? If so, I'd think it much more likely your particular car reads low, not that Hyundai's do in general. And are your tires the stock size?

I'll check mine when I get a chance. I bet a dollar to a donut it reads more/less spot on.

- Mark
 

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Dozens of cars, and many dozens of other owners of various Hyundai models, with a forum search here showing some others who stumbled across it on their own. Feel free to do your own test, or to not believe and use your trip odometer as is. It's not important for people who don't calculate fuel economy to the nearest tenth, although people who record mileage for reimbursement from their employer will be shorted a little.
 

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Dozens of cars, and many dozens of other owners of various Hyundai models, with a forum search here showing some others who stumbled across it on their own.
Still very skeptical as car companies don't generally deliberately bias something that costs them warranty money and makes their mileage look worse. I will check mine and report back.

- Mark
 

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There is a 1.5% difference in rolling dia between the 3 factory tire sizes. This can easily account for some discrepency in odometer readings. Then figure another 2% difference between a new tire and a worn tire. So we can see up to 3.5% difference. Which tire and under what wear level should the odometer be be "right"? My guess is that Hyundai calibrates the odometer for the smallest tire when worn to 2/32nd inch tread. This way there is no question when you go in for warranty work. IF it read 100% accurate when new, then, as the tire wore down, the miles indicated would add up quicker than actual miles driven. Not covering a repair at an idicated 100,509 miles, when the actual might have been 99,627 miles might be grounds for a lawsuit.
 

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There is a 1.5% difference in rolling dia between the 3 factory tire sizes. This can easily account for some discrepency in odometer readings. Then figure another 2% difference between a new tire and a worn tire. So we can see up to 3.5% difference.
Your figures sound unusually generous, but even if they are correct, I must point out that this would mean that most of us would have odometers more/less in the middle of this range of error (say around 1.7%), not at the 3.5% extreme where all factors break in one direction.

Not covering a repair at an idicated 100,509 miles, when the actual might have been 99,627 miles might be grounds for a lawsuit.
To support your point, Honda recently settled a class-action lawsuit where it was accused of deliberately having odometers read higher than actual. Honda's defense was that they were within established industry guidelines. Their problem was that their own documents showed that they were deliberately biasing the odometers high with tolerances of -1% to +3.75% with obvious benefits of reduced warranty, lease terms, etc. They've since said they now are tolerancing odometers to be centered on zero error. (Note that even though they paid out big money to settle this lawsuit, they are not erring on the conservative side to tolerance their odometers to read low so they never read high.)

I'm still very skeptical that Hyundai is going completely against the grain in the car industry by being so ultra-conservative in favor of the consumer when there is no regulation that says so and there is no general industry guideline that says that to never read high, you must bias your odometer low. I applaud them if they are, but I've never heard of this from any other source other than this single poster here.

I am curious to see what mine says.

- Mark
 

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I was getting 40+ mpg during highway driving before I bought new tires, but I'm getting ahead of myself.

After one of my POS OEM Continentals blew out its sidewall while sitting at a redlight, I was forced to replace all the tires with whatever the rats at the stealership had in stock. I now have 4 BF Good-for-Nothing Wrench G-Force Sports which barely let me get 30 mpg on the highway.

If I really push it with these tires I can see 35MPG. Really pushing it with the OEMs got me 50 mpg.

I'm really pissed about this since I didn't know I need special tires to get 40mpg with this little car. I now have 5k miles on the new tires and mpgs is really not improving.

My last Hyundai.
 

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I was getting 40+ mpg during highway driving before I bought new tires, but I'm getting ahead of myself.

After one of my POS OEM Continentals blew out its sidewall while sitting at a redlight, I was forced to replace all the tires with whatever the rats at the stealership had in stock. I now have 4 BF Good-for-Nothing Wrench G-Force Sports which barely let me get 30 mpg on the highway.

If I really push it with these tires I can see 35MPG. Really pushing it with the OEMs got me 50 mpg.

I'm really pissed about this since I didn't know I need special tires to get 40mpg with this little car. I now have 5k miles on the new tires and mpgs is really not improving.

My last Hyundai.
It makes no sense to me that you are faulting Hyundai for this. It is so widely known that Hyundai uses "low rolling resistance tires" in order to achieve the MPG figures that ARE possible. If you would have read the owners manual, you would have been aware of this.

You didn't have to go to the dealership to get tires. In fact, most people would highly recommend against it. You could have shelled out and bought some low rolling resistance tires, but you didn't. Tires fail from time to time; it's a fact of driving.

Research your purchases. Know what you are buying. Make mistakes and learn from them; don't place blame where it isn't due.
 

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I'm getting around 40 mpg 50-50 local/highway in NJ at an average 40 mph during peak commuting hours. I drive very conservatively - under 65 mph, cruise control, smooth acceleration, coasting, and low setting A/C when in use.
 

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I was getting 40+ mpg during highway driving before I bought new tires....I now have 4 BF Good-for-Nothing Wrench G-Force Sports which barely let me get 30 mpg on the highway....If I really push it with these tires I can see 35MPG. Really pushing it with the OEMs got me 50 mpg.
Other factors have to be involved. It is essentially impossible for there to be a 15 mpg difference attributable to the rolling resistance of a different brand of tires. The tires would be generating so much heat, they'd catch on fire.

- Mark
 
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