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Thread: new tires poor MPG?

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    new tires poor MPG?

    Just installed a new set of Kumho TA31 165/65R14 79T to replace stock tires at 44k miles. Pumped up tires to the max of 44 PSI. Got another alignment due to past problems and have adjustable camber bolts installed but alignment now shows good. Did another 0w-20 oil change, and replaced air filter for the heck of it.

    With all this done I am getting seriously poor MPG compared to before. I have to be doing 50 no stops to see 43+MPG and around town with stop signs I am seeing 30ish and getting around 38-40 doing 65 on the highway with AC on. Quite frankly I don't get why it has gotten to be so poor. Are the Kumhos that much worse than the enasaves?


    Last edited by Mirageman38; 09-11-2021 at 04:45 PM.

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        click to view fuel log View my fuel log 2019 Mirage ES 1.2 automatic: 38.8 mpg (US) ... 16.5 km/L ... 6.1 L/100 km ... 46.5 mpg (Imp)


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    Senior Member Top_Fuel's Avatar
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    You replaced your original Enasaves at 44K miles...which were probably fairly worn at that point, right?

    One thing to remember when tracking fuel mileage and you change tires is this: A new tire (of the same make/model) will always have higher rolling resistance than that same tire when it is worn out...because the new tire has more tread. Your worn out Low Rolling Resistance Enasaves were a very good tire for fuel mileage. They're lousy for everything else, but that's another story.

    So you replaced a worn out Low Rolling Resistance tire with a brand new non-LRR tire. So you have 2 things going on:

    1) You have a brand new tire with more tread...so it will naturally have more rolling resistance
    2) You opted for tires that aren't Low Rolling Resistance tires...so you definitely lost some efficiency there

    It's possible that those 2 things together may have cost you around 10% in a worst-case scenario. I would not expect your setup to cost you 10+ mpg. I wouldn't make any judgements until you have run a few tanks of gas on the new tires.

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        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 52.1 mpg (US) ... 22.2 km/L ... 4.5 L/100 km ... 62.6 mpg (Imp)


  3. The Following 2 Users Say Thank You to Top_Fuel For This Useful Post:

    dspace9 (09-11-2021),Mark (09-11-2021)

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    Senior Member dspace9's Avatar
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    I got 4 new Kumho's about a month and a half ago.

    The fuel economy numbers on my dash computer are worse by about 10% than the tires they replaced, my old used Dunlops.

    On my old Dunlops I was getting about 4.5 L / 100 kms with them on the best of days.

    Now with the Kumho Solus HA32 I believe, I get around 5.3 L / 100 km's, with lows of 4.8L / 100 km's so far. But the new tires handle way better in the rain.

    I wonder if you can really get 100,000 km's out of the Kumho's? That would make them a good bargain in the big picture.

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        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 42.2 mpg (US) ... 17.9 km/L ... 5.6 L/100 km ... 50.7 mpg (Imp)


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    I replaced two tires on my '16 Nissan Versa with stock size 185/65-15 Kumho Solus TA11's and have been getting great gas mileage out of them. They are currently at about 20K miles and show very minimal wear. I've got two more of the Kumho's in my storage building just waiting to go on when the other two wear out in probably about 10K miles. Only reason I bought them ahead of time is because I got a deal on them, both tires for under $100. As has already been mentioned more tread equals higher rolling resistance. When I replaced the Goodyear tires on my '97 Ford Escort wagon with Goodrich tires my highway mileage dropped about 20%.

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    Quote Originally Posted by dspace9 View Post
    I wonder if you can really get 100,000 km's out of the Kumho's? That would make them a good bargain in the big picture.
    Is that true? At 5L/100km you use 5000L on that 100,000 km. So a difference in economy of 10% is around 500L. Don't know your prices, but let's say $1.50/L, that is $750. Which means that these tires should be more than $375 cheaper than LRR's which last 50,000km to be a bargain.

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        click to view fuel log View my fuel log 2013 Space Star Cleartec Intense 1.0 manual: 55.4 mpg (US) ... 23.5 km/L ... 4.2 L/100 km ... 66.5 mpg (Imp)


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    Senior Member Cobrajet's Avatar
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    It has all been said, but putting soft, squishy, heavy tires on your Mirage is going to kill your mileage. Especially when you are comparing it to what you got with light, bald, overinflated, LRR tires in summertime.

    Sucks, but I bet the Kumhos were a damned sight cheaper than the Dunlops which might have given you 2-3 mpg more.

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    Quote Originally Posted by Cobrajet View Post
    It has all been said, but putting soft, squishy, heavy tires on your Mirage is going to kill your mileage. Especially when you are comparing it to what you got with light, bald, overinflated, LRR tires in summertime.

    Sucks, but I bet the Kumhos were a damned sight cheaper than the Dunlops which might have given you 2-3 mpg more.
    Kumho weigh less than the Federals, & I don't sense much of a difference in economy when using the Federals.

    Not sure how accurately tire companies list their tire weights, but Vredestein Quatrac 5 & Falken Sincera SN250A A/S tires are lighter than Dunlops.

    Vredestein/Falken are listed around 12 pounds.
    Dunlop/Bridgestone are listed around 13 pounds.
    Nexen are 13 pounds.
    Federal are 14.7 pounds.
    Kumho are 14.2 pounds.

    A new tire isn't going to compete with a worn out one when it comes to economy probably. I don't think the brand even matters at that point.

    Federal SS657 have somewhat disappeared. Don't see them listed very often any more.

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    Quote Originally Posted by Space Wolf View Post
    Is that true? At 5L/100km you use 5000L on that 100,000 km. So a difference in economy of 10% is around 500L. Don't know your prices, but let's say $1.50/L, that is $750. Which means that these tires should be more than $375 cheaper than LRR's which last 50,000km to be a bargain.
    Thankfully, we aren't paying much more than $0.80/L where I live.

    I don't buy the LRR hype at all, but some tires do have crappy traction & sidewall issues compared to others.

  10. #9
    Senior Member dspace9's Avatar
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    Quote Originally Posted by Space Wolf View Post
    Is that true? At 5L/100km you use 5000L on that 100,000 km. So a difference in economy of 10% is around 500L. Don't know your prices, but let's say $1.50/L, that is $750. Which means that these tires should be more than $375 cheaper than LRR's which last 50,000km to be a bargain.
    I was getting 4.7 L/ 100 km's on an empty tank earlier today, driving in 4th at around 85 km's an hour. Weather around 24 C or close to 80 F.

    So my New Kumho's are getting better and better MPGs. But if I can get like 5 years and 100,000 km's out of the tires, I would be willing to take a tiny cut out of my fuel economy numbers. Then I don't consume so much rubber. Remember we're talking like 49 miles a gallon to 47 miles a gallon. I misspoke, I should not have said 10%, looks like we're dealing with 5% or less.

    And I think my old dunlops, being worn out, explain why they got unbeatable fuel economy numbers. But no traction lol.

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 42.2 mpg (US) ... 17.9 km/L ... 5.6 L/100 km ... 50.7 mpg (Imp)


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    Quote Originally Posted by Mark View Post
    I don't buy the LRR hype at all
    Please elaborate...


    Resident Tire Engineer

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        click to view fuel log View my fuel log 2014 Mirage ES 1.2 manual: 44.4 mpg (US) ... 18.9 km/L ... 5.3 L/100 km ... 53.3 mpg (Imp)


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