# If you like your fuel economy, choose your tires carefully



## johnmo (Mar 2, 2017)

I was surprised and happy that I got over 60k miles out of the OEM Goodyear tires, but tire time came and I wanted some black wheels, so I went up to 17" wheels and put on some 205/55R16 Continental PureContact LS tires.

I'm not sure which piece of this setup is the biggest culprit, but my fuel economy dropped dramatically. In the middle leg of my commute where I used to routinely top 70 MPG on my last 25-mile average and where I've hit 80 MPG a few times, I struggle to top 60 MPG now. Hand-calculated tank averages are running 50-52 MPG, which, while still pretty respectable, is a big shift from the easy 55+ MPG I used to get. I doubt I'll see a 60 MPG tank with these wheels and tires.

The PureContact LS is listed an "Eco Foucs" tire and I have them aired up well above what's specified on the door sill. I guess there's something in the tread or tread compound or just that little bit of extra width that makes all the difference. It feels kind of like it did with the Goodyears when I was driving in the rain, which always ate into fuel economy a little.

Now, it handles great. The tires are slightly wider and the sidewall is stiffer and understeer isn't a thing any more. And it looks pretty sharp with the new wheels. But I really miss going 700 miles before the fuel light came on. I'm fueling up between 600 and 650 miles now.

So... choose carefully if you want to keep your fuel economy.


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## Ma v e n (Oct 8, 2018)

It's probably the wheels.


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## Cruzen18 (Jan 28, 2018)

Whats the difference in total wheel weight versus what you replaced. Wouldn't take much additional weight to affect the mpg


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## obermd (Mar 3, 2012)

You indicate the new rims are wider. Wider tires have more rolling resistance.


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## Blasirl (Mar 31, 2015)

Go with the 17" ECO rims for the best weight savings - stock anyways


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## johnmo (Mar 2, 2017)

I went with RTX Black Widow wheels. I can't find any information about what they weigh, but it has to be a little more than stock. I was kind of surprised that neither the stock nor the custom wheels felt very heavy, but I'm not used to handling wheels without tires either.

Maybe I'll have the OEM wheels powder coated black and switch back in another 60k miles.


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## jblackburn (Apr 14, 2012)

My initial impressions are that I seem to have lost about ~3 MPG switching from my worn out MXM4 to PureContact LS.

But I went up a size on sidewall (40 to 45), so the speedo is off by 2-3 MPH too.

Hopefully it will increase as they wear in a bit; this was my first highway trip with them. I am EXTREMELY happy with the tires otherwise.


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## RichLo1 (May 31, 2018)

Yes tires have a big effect on mileage however my OEM Goodyears had more road damage than any tire Ive ever seen. By the time I replaced them I had at LEAST 12 patches in them leaving me limping to a tire shop and costing $30 each time. Before these tires, I've only had to patch 3 tires in my life (I've been driving for 15 years).

After that experience, I dont care how much tires save on fuel, that fuel savings doesn't cover all those patches and lost time at work having to deal with flats all the time. If I could I would run 10-ply, Load Range-E, Light Truck tires on my ECO just to never have a flat again.


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## Taxman (Aug 10, 2017)

jblackburn said:


> Hopefully it will increase as they wear in a bit; this was my first highway trip with them. I am EXTREMELY happy with the tires otherwise.


Good point, new tires always have high rolling resistance. 
But if they're still doing it 5000 miles later...


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## plano-doug (Jul 1, 2015)

RichLo1 said:


> ...my OEM Goodyears had more road damage than any tire Ive ever seen. By the time I replaced them I had at LEAST 12 patches in them leaving me limping to a tire shop and costing $30 each time.


You might be a good candidate for a road hazard warranty  

Seriously, I pay 15-25 $ per tire to add the warranty, and I'm pretty sure I'm getting my money's worth. It seems like, besides occasional 0-cost patches, I average one tire replaced per set due to some sort of hazard, whether it's one of my kids hitting a curb, or a nail in the shoulder (where it's unsafe to patch). I've had several tires replaced with the only cost being another 15-25 $ for the new warranty. 

Doug

.


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## froyofanatic (Jul 16, 2018)

Agree that it's probably the extra unsprung weight you're adding from the wheels, in addition to the added rolling resistance.

These 225 section tires on my RS stick like a mutherfunker but yeah, I'll never get those fuel economy numbers that you're talking about.


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## Barry Allen (Apr 18, 2018)

If you spend money on new wheels when the original wheels on your car were perfectly fine, you don't really have a basis to complain about fuel economy.


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## johnmo (Mar 2, 2017)

plano-doug said:


> Seriously, I pay 15-25 $ per tire to add the warranty, and I'm pretty sure I'm getting my money's worth. It seems like, besides occasional 0-cost patches, I average one tire replaced per set due to some sort of hazard, whether it's one of my kids hitting a curb, or a nail in the shoulder (where it's unsafe to patch). I've had several tires replaced with the only cost being another 15-25 $ for the new warranty.


With very, very few exceptions, I've bought the road hazard warranty and without exception I've never regretted it. I don't think I've ever had a set of tires where I didn't have to have at least one of them patched and there have been a few sets where I've had to have a replacement. The value returned on the number of replacements I've had to have probably covers the cost of all of the tire warranties I've bought.


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## johnmo (Mar 2, 2017)

Barry Allen said:


> If you spend money on new wheels when the original wheels on your car were perfectly fine, you don't really have a basis to complain about fuel economy.


I'm such a complainer, man. :dry:

I've never been one to mod cars much, especially for looks. I went back and forth a long time before I convinced myself to drop the money on the wheels. My wife asked me what finally got me to do it. I told her it's cheaper than a Camaro. Fuel economy is still a lot better than a Camaro too. 


I'm OK with trading off some fuel economy for some frivolous fun and better handling. But I was surprised by how much impact there was on fuel economy. Not so much a complaint as a warning to others.


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## Cruzen18 (Jan 28, 2018)

johnmo said:


> ...it's cheaper than a Camaro. Fuel economy is still a lot better than a Camaro too.


Not near as much fun to drive tho...hmy:


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## johnmo (Mar 2, 2017)

Cruzen18 said:


> Not near as much fun to drive tho...hmy:


You're not wrong.

I've driven high-performance Camros and Mustangs. They're a blast. Can't see me doing a 100+ mile daily round trip in those though. I've got a little extra money to drop on fancy wheels, but I don't have stupid money for double the vehicle purchase price and twice as much on fuel.

Everything's a compromise.


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## Cruz15 (Mar 17, 2016)

Metal will always weigh more than rubber by a huge margin. Wider rims and wider tires, then just make the difference even larger.

The mileage you get from a really worn out tire will always be much better than a stock tire. Did they do an alignment as well? That could seriously
make that much difference if any angle was changed. The original spec is set for mileage I would think not handling.


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## rcruze (Mar 22, 2018)

I just got my new tires yesterday (64K miles on OEM) and was talking to the sales guy about weight. I went with stock size tires while I looked at options. I would be interested in hearing your longer term report on MPG...My first full commute to work today I was at 57.1 which is still in my normal range. 

If you could find the weight difference between stock and your new setup, Maybe you could find things to remove from the car to make up the diff.. just a thought..


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## Cruzen18 (Jan 28, 2018)

rcruze said:


> If you could find the weight difference between stock and your new setup, Maybe you could find things to remove from the car to make up the diff.. just a thought..


or tune it to offset the difference of the extra weight and additional drag from the larger tires.


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## cyclewild (Aug 14, 2013)

Except you're talking unsprung rotational weight vs. sprung static weight, huge difference.


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## MP81 (Jul 20, 2015)

johnmo said:


> I was surprised and happy that I got over 60k miles out of the OEM Goodyear tires, but tire time came and I wanted some black wheels, so I went up to 17" wheels and put on some 205/55R16 Continental PureContact LS tires.


Wait, did you go up to a 17" wheel or did you stay with 16s? You said 17" wheels, but listed the stock-size 16" tire size.


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## johnmo (Mar 2, 2017)

MP81 said:


> Wait, did you go up to a 17" wheel or did you stay with 16s? You said 17" wheels, but listed the stock-size 16" tire size.


D'oh! You're right. I did go up to a 17" wheel and I put on *225/45R17* tires. That's the OEM size for 17" wheels. The total tire diameter is within fractions of what it was. My speedometer is a fraction higher compared to my GPS speedometer. It was dead on before and now my speedometer leads my GPS slightly -- seems like about .5 MPH.

I guess I was thinking I went from 205 to 215 or 215 to 225, but the jump from 205 to 225 is more significant. I think the wider tires probably have more to do with the fuel economy drop than anything. Weight is a factor, but increased weight would also tend to keep me moving once I get moving. Increased weight being more of a factor from a stop and less of a factor at speed on the highway. I spend most of my time on the highway.

And, who knows how, but I think it's screwed with the fuel computer more than anything. I filled this morning with the DIC showing 49 MPG and the manual calculation was 53 MPG. The DIC has always been a little more pessimistic. 53 MPG is off a little, but still pretty good -- it's more in the ballpark of the 1 or 2 MPG I thought I might lose. But the fuel computer tops out 10-20 MPG below what I'm used to seeing.

To answer another question, yes, I got an alignment. And that could make a difference, but nothing I can tell in the steering or handling.


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## jblackburn (Apr 14, 2012)

johnmo said:


> D'oh! You're right. I did go up to a 17" wheel and I put on *225/45R17* tires. That's the OEM size for 17" wheels. The total tire diameter is within fractions of what it was. My speedometer is a fraction higher compared to my GPS speedometer. It was dead on before and now my speedometer leads my GPS slightly -- seems like about .5 MPH.
> 
> I guess I was thinking I went from 205 to 215 or 215 to 225, but the jump from 205 to 225 is more significant. I think the wider tires probably have more to do with the fuel economy drop than anything. Weight is a factor, but increased weight would also tend to keep me moving once I get moving. Increased weight being more of a factor from a stop and less of a factor at speed on the highway. I spend most of my time on the highway.
> 
> ...


The EPA MPG difference on 1.4T variants between the LT and Premier is 1/2 MPG (city/hwy - or was before they re-rated it for the 2017 EPA cycle adjustments), and the only real difference is the tires/wheels.

I can confirm in the 4 weeks I had with a LT loaner that it got in the neighborhood of ~2-3 MPG than my Premier in similar driving. 16" Hankook's on the LT RS.


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## MP81 (Jul 20, 2015)

Aha, that makes more sense! Haha.

Yeah, the extra width definitely doesn't help on the fuel economy spectrum.

Looks like the 225/45R17 PureContact LS is a 23 lb tire, while the 205/55R16 Fuel Max is an 18 lb tire - so a solid 5 lb increase per corner. Definitely a contributor as well.

I'm not sure what the stock 16" wheels weigh (I know on the 1st gen, we have wheel weights for all of them, but haven't seen anything similar for 2nd gens yet), but I also can't seem to find what the RTX wheels weigh, either. Amazon says the shipping weight is 12 lbs, but I can't believe that is correct.


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## 72chevman (Dec 28, 2018)

I just bought a used 2016 Limited 1.4 auto. The dealer installed new Mastercraft LSR 216/60/16 tires. I was averaging almost 30 for my daily driving(most highway). Took it on a highway trip and couldn't get better than 33. My daughter has a 2013 1.8 with 60K factory tires and gets better MPG. I just installed 17" rims with 215/55/17 Continental Pure Contact LS and my in town MPG jumped immediately to 33. I have not been on a trip yet. I think the Mastercraft were just crap for rolling resistance. Adding 20mm per tire of wind and ground resistance probably did you in.


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