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New Tires = 5 to 6 Less MPGs

Discussion in 'Prius c Fuel Economy' started by Lukey51, Sep 9, 2022.

  1. Lukey51

    Lukey51 Active Member

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    In May I put a set of new Falken Sincera tires on my 2012 Prius C and I now get 41 or 42 around town and about 55 MPGs on the highway, whereas I used to get about 47 MPGs around town. I spent $520 which is the most I've ever paid for a set of 4 new tires. What I was running were Goodyear Assurance tires that had abut 3 or 4/32" left on the tread. I have a feeling I would have lost some MPGs even if I had put new Goodyear tires on it.

    Is that expected for new tires or was I wrong to have not paid more for tires with less rolling resistance?
     
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  2. jdenenberg

    jdenenberg EE Professor

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    You purchased tires that have poor reviews on Tirerack.com. I always buy LRR tires for my hybrid card with my favorite being Nokian WR series tires. Yes, they cost a bit more, but are stronger tires (H-Rated, 51 PSI max), have better traction/handling is all weather conditions (they are as good as many winter tires in snow), and last more than 50,000 miles. The additional MPG will save you more than the extra cost over the life of the tires.

    JeffD
     
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  3. bisco

    bisco cookie crumbler

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    because the new tires have a larger circumference, it does alter the speedo/odo

    and new tires sometimes need to break in, so hopefully mpg's will improve a bit.

    the rest is the type of tire, LRR does make a difference
     
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  4. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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  5. wjtracy

    wjtracy Senior Member

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    Years ago TireRack used to have good article quoted here often about putting same tires back on you will see x% decrease in MPG due to mainly more rubber as some above mentioned and I forget if there are other factors
     
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  6. TMR-JWAP

    TMR-JWAP Senior Member

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    On my 2007 Touring:
    Purchased Feb 2017 with about 143,000 miles

    4/15/2017 was returning from an Atlanta trip when started getting a thumping noise about 5 miles from home. Found a huge bubble in front driver side tire sidewall. Limped my way to nearest tire store that was open on a Sunday. PepBoys.
    All they had in stock for 195/55/16 was Falken Ziex ZE950. Had 4 of them installed and drove off. $447.77 out the door. 146,939 miles.

    5/25/2020 Front tires were worn more than back, got a nail right at edge of tread on driverside front. Same PepBoys. New tires, front only. Same model tire and size. $212.85 out the door. 197,766 miles on the car. ~51k miles on the tires.

    Middle of August 2022. Got a screw in driver side rear tire. Plug didn't seal perfectly, so still has a slow leak. Have to add air every 3 or 4 days. End of August hit the deepest pothole ever in my life. Felt like it ripped the driver front tire off. Put a wrinkle in the sidewall. Couldn't get new tires yet due to work schedule. The ZE950 no longer available. Just used backup 2008 prius for a while. ~226,000 miles on car. Plenty of tread on fronts, backs are at the wear indicators. The backs lasted from ~147k to 226k. That's not bad...79k miles....just going to replace all 4 due to the pothole damage. I've been surprisingly pleased with how the tires have performed. I've had plenty of 54+ mpg tanks.

    The ZE950 has been replaced by the ZE960 I believe. They run about $110 each near me, but availability is sketchy. I said the heck with it and just ordered (4) 205/55/16 94V Solarus Starfire? (by Cooper) with installation scheduled for 9/17. $281.02 for the tires and I'll pay $17 each for install --> so $349ish out the door. Decided to go with the 205 just to gain a bit of car height for some speed bumps I deal with now and then, plus it will make the speedo dead nuts instead of reading slightly low. Will be interesting to see how these cheapass tires hold up and how the MPG changes, if at all.
     
    #6 TMR-JWAP, Sep 9, 2022
    Last edited: Sep 9, 2022
  7. PriusII&C

    PriusII&C Active Member

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    There are at least 3 factors that contribute to lower MPG on new tires:
    1. Larger diameter (pseudo lower MPG)
    2. Heavier (more weight the car is carrying)
    3. Softer (more deformation energy loss)

    The reduction in MPG is normally around a few % (in comparison with old tires of the same brand/model). However, if you use different brands/models, then there will be more (and maybe bigger) variables.
     
    #7 PriusII&C, Sep 9, 2022
    Last edited: Sep 9, 2022
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  8. 9001MPG

    9001MPG Junior Member

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    Check EU tire labels when buying tires I'm assuming you're running the size: 175/65R14 (from memory that's what the Prius C runs?) Looking at the manufacturers site we see it gets a C rating on rolling resistance: Falken Tyres

    upload_2022-9-10_19-42-57.png


    a rating of C indicates the following rolling resistance (kg per ton of vehicle mass)
    (see page 3 of attached PDF for full details).

    upload_2022-9-10_19-40-14.png


    Best rolling resistance, while still having very good dry/wet handling is the Continental EcoContact 6, it does sacrifice wear rating for this, but it's on a prius, it'll last forever anyway. Gets an A on rolling resistance, and B wet handling rating. Are you able to exchange the tires?
     

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  9. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    There's always some variability with tires, but also check your calendar. You probably weren't using as much air conditioning back in May.

    Wait to see if the numbers improve as the season cools.
     
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  10. sam spade 2

    sam spade 2 Senior Member

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    Falken is not a widely known brand in the US.
    What caused you to choose them ??
    Yes, I think you make a bad choice.
    Others have explained why.
     
  11. Lukey51

    Lukey51 Active Member

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    I have doubts about that.
    I only drive 3500 to about 4000 miles a year now, and mostly around town miles.
    So, if I saved 3 MPGs by buying new Goodyear Assurance tires, it seems that I'd save a few bucks a year and it would take about 20 years to recover the additional cost. I haven't added it up on paper to get the real numbers, and I don't think it would be worth the bother.

    My old tires were hard rubber and didn't have very good stopping power.
    I skidded with them one day on dry road just by hitting the brakes a little harder than normal.
    The new tires are much softer, mostly due to being new, IMHO.
    The car is in my garage most of the time and this should help preserve the rubber for a good many years.
    I will likely get at least 10 years out of these tires, maybe even 15 or more years. They're rated for 80k miles.

    So, IDK. I lost more MPGs than I had planned on but if I could go back again, I'd still probably buy these or similar tires.

    The owner of the tire store recommended these tires to me.
    He runs them on his Lexus ES 300.
     
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  12. Lukey51

    Lukey51 Active Member

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    I've still got a car that gets 42 / 55 city / highway.
    That's not bad in my book.
     
  13. bisco

    bisco cookie crumbler

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    if it's strictly a money issue, and not fossil fuel conservation, you may be right
     
  14. Lukey51

    Lukey51 Active Member

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    I care a lot about reducing my carbon footprint.
    I didn't think spending a lot more on tires would make much of a difference.
     
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  15. bisco

    bisco cookie crumbler

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    some here say that a fairly inexpensive tire (general altimax, or something) is an excellent tire, idk.
    i spent $700. on michelin energy savers just to get a quieter ride and the same mpg's.
     
  16. TMR-JWAP

    TMR-JWAP Senior Member

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    If the difference between a LRR tire and a normal tire is going to be something that one is truly worried about IRT fossil fuel and carbon footprint, I think that person needs to invest in good walking shoes and start putting down real footprints...Just having the Prius at 45mpg-ish is like filling a gallon jug with carbon footprint savings. A few more drops in the jug just doesn't matter enough to worry about. And when you have countries like China and India blowing the bottom out of the jug with dynamite, we're all just peeing in the wind anyway.....
     
  17. Lukey51

    Lukey51 Active Member

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    I really don't know.
    It seems that I'd never be able to recover the added expense if I did.
     
  18. Lukey51

    Lukey51 Active Member

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    I don't use much AC.
    I usually do all my driving in the mornings before it gets too hot.