Michelin Energy Savers lowering MPG?

Discussion in 'Gen 3 Prius Fuel Economy' started by gustibus, Nov 10, 2014.

  1. gustibus

    gustibus New Member

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    Hey folks, so I recently purchase a set of Michelin Energy Savers (195/65/15) for my prius THREE. I am noticing a decrease in MPG (as much as 5-10 mpg) as opposed to what I thought was going to happen. Has anyone else experienced this, and if not, does anybody have any suggestions? I increased pressure to 40/38 today to see if it would help, and it really doesn't seem to be doing much. I'm also taking into account the recent temperature drop, but it never seems to have dropped that much before so suddenly and noticeably.
     
  2. Jeff N

    Jeff N The answer is 0042

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    What kind of tires did you have previously and how worn down was the tread? How many miles do you have on the new tires?

    Old worn down tires have naturally lower rolling resistance than new tires with deeper tread. New tires also have a thin layer chemical coating left over from manufacturing that reportedly takes a few hundred miles to wear off.

    The real comparison is between different tire designs when they are at the same condition.
     
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  3. vskid3

    vskid3 Active Member

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    What pressure did you have in the old tires and what were the new tires at before you filled them? If you had your old tires at 40/38psi, that plus the new tires needing to break in like Jeff said and the colder temps could very well be the cause of the drop in MPGs.
     
  4. matt b.

    matt b. Member

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    I have a Michelin energy saver a/s LRR tires and my mileage has increased. I tried Yokohamas and a few others but these were the best tires for mileageanother thing you might want to try is going 41 psi all the way around

    but this is coming from someone who lives in Southern California so we don't really know what cold is lol
     
    #4 matt b., Nov 11, 2014
    Last edited by a moderator: Nov 28, 2014
  5. gustibus

    gustibus New Member

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    The factory tires were Yokohamas, but I never bothered to check the style. My error, sorry. They were only ever inflated to the factory recommendations. I had them for 50K miles, and the tread was very very worn down at the end; again, not certain of precise measurements but I was told at the dealer they were just one step above replacing them. The new tires have 350 miles on them.
     
  6. Jeff N

    Jeff N The answer is 0042

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    I think you just need to wait it out for at least a couple of thousand miles for the new tires to break in.

    I had a similar experience switching from worn Goodyear Fuel Max tires at 57,000 miles to Michelin Primacy MXV4 tires. MXV4 tires had a good LRR rating from Consumer Reports but it turned out that the tire size CR tested and the actual tire size I needed on my car had quite different tread depths and tread widths so mine didn't roll as well for quite awhile.

    In your case, Energy Savers are known for very good mpg for your tire size. Don't worry about it. The tires should have excellent mpg on average over their service life.
     
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  7. magnumrtawd

    magnumrtawd Member

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    What is the mpg your getting?
     
  8. gustibus

    gustibus New Member

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    @magnumrtawd never more than 52 mpg. I was never getting less than 50 mpg before the switch
     
  9. F8L

    F8L Protecting Habitat & AG Lands

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    The Energy Saver A/S will it cause a loss in mpg unless you have a defective tire. They are the most efficient tire available in the 15" Prius size. All tires have a break in period and JeffN covered the rest.

    Did you purchase the Energy Saver (summer tire) on accident?
     
  10. Fore

    Fore Don't look back!

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    Relax, it takes time to break them in. In the summer I was averaging around 54mpg. I live in VA too so were now in the winter temps, they've added winter mix into the gas so I'm now averaging around 45mpgs. Be happy, you bought great tires!
     
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  11. HaroldW

    HaroldW Active Member

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    I would take them back as you should not be taking that kind of a hit. Energy Savers are normally good at the start. Maybe michilen guality is going south!!! H
     
  12. F8L

    F8L Protecting Habitat & AG Lands

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    Not even close. :) Michelin is always in one of the top 2 spots of a class competition. There is a reason they are pricey.
     
  13. Mike Vaughn

    Mike Vaughn New Member

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    I had to take an emergency trip from Frederick Maryland to Palm Bay Florida last week. The one-way distance was about 930 miles all high-speed interstate about 13 hours. At an average speed of 74 mph I achieved over 45 miles per gallon reading on my 2010 Prius IV with the original tires. As I had over 48,467 miles on the old tires and the treadwear was very thin, I purchased 4 new Michelin Defender XTs 195/65 R15 at BJ's in Palm Bay Florida. BJ's indicated that they set the air pressure at 33/35. I made the nonstop trip back yesterday along the same route however my gas mileage dropped to less than 36.5 miles per gallon. I also noticed the week that I drove around in Florida on the new tires my gas mileage had dropped to 38. I just check the tire pressure this morning on cold tires and I found that the tire pressure was in actuality 30 in the front and 32 in the back so I'm hoping that putting in the correct 35 in the front and 33 in the back will correct some of the MPG issue. Does anyone else have any suggestions?
     
  14. F8L

    F8L Protecting Habitat & AG Lands

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    Mike, the Defender is a good tire and should last a long time but you will always suffer a mpg loss with them compared to the OEM tire or the Energy Saver A/S. The Defender is just not a very fuel efficient tire. The good news is you are losing the bulk of your mpg due to:

    1) Low tire pressure
    2) Brand new tires that are not broken in

    Air up your tires for immediate gains. Then wait a couple thousand miles for the tires to fully break in and the mpg to settle. You'll probably only lose 2-4mpg average over the OEM tire when it was new too. Because your mpg is extremely new I would also assume there must have been elevation or weather changes as well. Add a little water on the road and you cannot make any serious conclusions on mpg performance.
     
  15. JimN

    JimN Let the games begin!

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    A temperature change of 10 degrees (F) will cause a 1 psi change in tire pressure. Losing 3 or 4 psi between Florida and the Northeast in the winter is expected.

    Mike, did you always run on 35psi? IMO, that's low for a tire rated at 44 or 51psi.
     
  16. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    ^ Let's not lose sight of: 35 psi range is what Toyota specifies, for 15". If you roll into Costco or a dealership that's what they'll set the tires at. The "rating" (embossed on the tire sidewall) is the max safe pressure at max load.

    That said, I set my tire pressure higher than spec, by a bit.
     
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