Milage drops with new tires

Discussion in 'Gen 4 Prius Main Forum' started by jerryd, Oct 23, 2021.

  1. jerryd

    jerryd Junior Member

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    Prius Forum,
    I recently replaced the original tires on my 2018 Prius 4. I wanted quiet
    tires so got Firestone Champion Fuel Savers. I pumped them up to 42 front
    and 40 rear which is the same as the originals and have 2000 miles on them.
    They are very quiet but I was getting 56+ mpg(often 60+ on long trips) before
    the new tires but now it's hard to get even 53.

    Any suggestions?

    jerryd
     
    #1 jerryd, Oct 23, 2021
    Last edited: Oct 23, 2021
  2. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I think the thread title contains the answer.

    That said, some new tires can shine: With a previous vehicle, I got Bridgestone Ecopia EP20 one time; mpg never skipped a beat.

    But typically, not so much: last time I got new tires, for our 2010 Prius, going from well-worn, 9~ year old Michelin Pilots to Michelin Primacy (17" rim size), there was a dismaying mpg hit. Just getting back now, a couple of years later.

    Suggestions? If you're otherwise happy with them, give them time.
     
    #2 Mendel Leisk, Oct 23, 2021
    Last edited: Oct 23, 2021
  3. sclevine

    sclevine Member

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    as tires get worn in over time there will be less resistance and therefore more MPG. I've changed tires twice and both times experienced a pretty significant drop in MPG which improved again over time.

    First replacement was Ecopia's and 2nd was Defenders, and neither have lived up to the MPG's of the OEM tires.
     
  4. MichelleStone

    MichelleStone Senior Member

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    I went into my dealership and specifically asked for LRR tires that would match the performance of the factory tires. My lifelong MPG was 62 miles a gallon. They hooked me up with a set of Michelins. I remember getting some long wear Michelins many years ago on my mini van. They were the hardest tires I've ever driven on and so I thought they'd be a good match since factory tires were not available. Sadly, they are not. They proved a much more comfortable drive but my mileage has dropped significantly. I'm getting mid fifties performance. Still, I'm happy with the car. I had expected to only get 48 MPG when I bought it in 2016.
     
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  5. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Keep in mind there's little or no upside for the dealership to do tire research for you, and they're rarely the best price either.

    That's not to say never consider them. If the car's there anyway, for example. Or if it's a little complicated: for example, when I got snow tires for our 2010, I went with Corolla rims a dealership supplied (for a good price), and let them do the full install, with tires I spec'd. In that instance there was a question mark as to whether the Corolla rims would even fit, so I let them take it all on.

    But for simple tire replacement, I'd do my own tire research, and give the work to a tire specialty place.
     
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  6. abksports

    abksports New Member

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    Just to weigh in on the tire issue, I have had a terrible experience with Michelin Defenders on my '06.

    For the first few sets of new tires, I went with the stock Goodyear Integrity tires, which were great for maintaining MPGs, but not so great for handling in inclement weather.

    So, I decided to try Michelin Defenders- BIG mistake. For gas mileage, at least. It has delivered a terrible blow to my average MPG; since I put them on, I have to fill up so much more frequently than ever before. Now, the car is 15 years old and at about 298,000 miles (burning oil, etc.), so I know that MPGs are going to go down anyway. But the Michelins made the car SO much less efficient.

    I was going to take them off and sell them, but I decided to just eat it and let them wear out since I paid a hefty price for them (plus, they are actually good tires in terms of gripping the road).

    So my advice for mileage-conscious Prii owners would be to steer clear of all Michelin tires, especially Defenders.
     
  7. jdenenberg

    jdenenberg EE Professor

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    I, and most of you on this forum, bought a Prius to get a high MPG. When replacing tires the first thing I look for is an "energy saving" claim by the manufacturer. Several Tire manufacturers do have specific model tires that are designed to have a Low Rolling Resistance (LRR) but there is no standard for how efficient the tire needs to be to get that claim so YMMV.

    I have seen statements about "after break-in your MPG will improve". I have never found this to be true. There are two factors that cause an immediate difference in perceived MPG besides the rolling resistance:
    1. Tires, even those that are rated at the same size, will have different revolutions/mile which will change the calibration of your odometer and speedometer.
    2. As a tire wears, the tire diameter and circumference is reduced by about 2-3% over its life. This again increases the revs/mile so you see an apparent MPG reduction even when replacing tires with the same model/size.
    I have had great results with Nokian WR, WRg2. and WRg3 tires (They are now delivering WRg4 which I will buy for my 2020 AWDe when the )E tires wear sufficiently to justify replacement). The OE tires that came with my three Prii did well on MPG, but had serious performance issues: (bad tread wear on 2004 Goodyear tires and poor wet/snow traction on Nano-Energy). I have also had Michelin MVX4+ (energy saving) tires that performed well. but were not as energy saving as the Nokians.

    You need to do your homework as the manufacturers claims are not standardized tests. If you rely on Tire Rack (generally a good source of tire information), just remember that they do not review tires that they do not sell (Nokians for example).

    JeffD
     
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  8. farmecologist

    farmecologist Senior Member

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    I'm putting a set of Michelin X-ice Snow tires on my daughter's Prius C. Now THAT should be and interesting MPG comparison. (y)
     
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  9. KrautBurner

    KrautBurner New Member

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    I purchased my 2010 prius with about 46K miles on it (in 2014) and it had a brand new set of Michelen Defenders (I think)
    I replaced them at about 110K miles with a set of Defender T+H (was averaging 50-53mpg)
    I saw about a 5mpg drop (10%) right away, I've now got nearly 202K miles (90K miles on these tires), I'm still averaging about 44-46mpg (I've not seen an entire tank average over 50mpg since changing tires)

    my drive is pretty consistant, 115 miles/day, almost all 55/60mph (speed limit) going 60-65mph, with lots of elevation change

    I'd love to get some tires that get me back above 50 mpg
     
  10. alanclarkeau

    alanclarkeau Senior Member

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    I think the "Defender T+H" is an all-season tyre, which typically won't get quite the economy of a standard ECO tyre.

    I haven't used either of those - but someone else might chip in who has.
     
  11. CooCooCaChoo

    CooCooCaChoo Active Member

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    Defenders, whether sold as a Costco branded tire or a Michelin tire are not the best rolling resistance tire. You will not get good fuel economy from them, vs. say Ecopias.

    Yes, they handle a bit better than Ecopias, but is the drop in fuel economy going to be justifiable for you?
     
  12. Mendel Leisk

    Mendel Leisk Sand Pounder

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    IIRC, Defenders were badged “Green-X”, and the “T+H” iteration are “Total Performance”. Doubt you could get a straight answer out of Michelin regarding the difference, if any.
     
  13. Ramo_958

    Ramo_958 Junior Member

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    A couple of weeks ago I replaced the tires on my 2018 Prius with Continental TrueContact tires. So far I'm very pleased, gas mileage slightly dropped from 58 to 55 MPG.

    Posted via the PriusChat mobile app.
     
  14. Pulse07

    Pulse07 Member

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    Any love for Michelin Primacy A/s? Had them on a Civic and an Accord. LOVE it. Although checking Costco , they actually dont sell Michelin Primacy A/s for the Prius's size, although America's Tires do .
     
  15. ken2116

    ken2116 Junior Member

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    Fuel economy is very important to me, but I value safety more. To me this mainly means stopping distance, both wet and dry, emergency handling, and the ability to survive hard knocks that might cause a blowout and loss of control. We've used a variety of Michelin All Season (AS) tires for decades because, compared to others we've tried, they consistently performed very well in these departments - have survived some incredibly bad potholes at high speeds, and perform quite well in all conditions including the snow & ice encountered in the Sierra (until recently other manufacturer's AS tires could be quite poor in winter conditions) and they use high quality rubber that resists environmental cracking way better than many. Comparing tires for our 2019 Prius at the America's Tire site, of those where stopping distance is listed, Michelin Defenders rated the best by 5 to almost 10 feet, which can be the difference between a close call and a serious accident.

    We're about to replace the Dunlop Enasaves that came on our Prius, which at 42kmi. are at 4mm tread. We've had no complaints about them (for 3-season driving, we take another car to the mountains in winter), but reviewers on the Americas Tire site report they've repeatedly gotten nearly 80kmi from Michelin Defenders on Priuses, cutting tire expense and landfill impact by nearly half compared to almost two sets of the Dunlops needed to go the same distance. As for fuel economy, if the Michelins reduce the mileage by 10%, that would amount to ~ 140g. over the 80kmi life of the tires, or $490 (at $3.50/g), which is less than the second set of Enasaves we'd need over the same distance, and with improved safety.

    Also as others have mentioned, because worn tires are smaller diameter, have older (harder) rubber, and less tread squirm (shallower tread) than newer tires, one should expect both indicated and real mileage to drop, even when replacing with the same model.
     
    #15 ken2116, Nov 17, 2021
    Last edited: Nov 17, 2021
  16. Chris Wolfgram

    Chris Wolfgram Active Member

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    Now this is interesting. I changed my tires to some cheapies... don't even remember the name without walking outside... but anyway, my mileage did start dropping from like 52.6 down to 52.0, and I was thinking, "Well that sucks, I'll be down to 50 before I know it" ! But then it seems to have stopped right at 52.0 ? That would be great if it actually started going back up just a little bit now ? Never even considered that that was possible. Hmmm.
     
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