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From Fred flinstone Tires to Michelin energy saver A/S and a fixed TPS

Discussion in 'Gen 2 Prius Fuel Economy' started by ls40095, Jan 24, 2013.

  1. ls40095

    ls40095 Junior Member

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    I thought I knew the value of having proper tires on a Prius until recently. I mean, How much difference can it make? 4-5 mpg max?
    Thats what I thought until ....

    We bought our first Prius last year, a clean Beautiful dark Gray 2007 (98k) with just about everything but Nav....I completed all what I thought was the necessary maintenance (M1 5/30 Oil change, Trans fluid, Wiper blades, Air filter, Belt, Spark Plugs, Clean throttle body, Engine/Inverter coolant, grill block, State Inspection, New carpet mats and its first front brakes.

    The car has a great set of Michelin X tires with about 10k on them. I recently completed a trip to Florida where my best tank of fuel yielded 53.4 mpg and a tad over 500 miles... I have a scan gauge and try to keep my ignition timing as close to 13 or 14, so I do drive like a grandad most of the time.

    Last week I purchased another 2007 comparably equipped with low miles (56k)....To this point, Ive replaced a dirty air filter, got the State inspection, filled up the tank with gasoline and changed the oil with Mobil 1 5/20.

    The car runs fine but has a set of Kelly Navigator touring gold tires...Driving over the past 3 days, Ive put close to 100 miles on the car and am barely nearing 40mpg...the difference in the rolling resistance and noise is mind boggling, its downright ridiculous. It sounds like I need 4 wheel bearings. The tires and belts look fine, they look to have about 30,000 miles of tread wear remaining and I'm not getting that Flop, flop, flop you would get from a bad tire that's been sitting for a long period of time...

    So today, after 3 days, I went to Costco and ordered 4 Michelin Energy Saver A/S.

    With the $70 off discount to pre-order cost me $493.68 total (including mounting and balancing)

    What was also cool is the guy at Costco is going to fix my TPMS on my other Prius for $60. It had an OEM tire valve replaced improperly so that wicked tire pressure light is always on. I cant imagine getting that done at the stealership for less then $150....

    So , what do you think my MPG is going to increase to?
     
  2. SteveLee

    SteveLee Active Member

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    We will be very interested in hearing.
     
  3. bisco

    bisco cookie crumbler

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    welcome, i hope it gets you upto 65 like i used to get in my 08, all the best!
     
  4. uart

    uart Senior Member

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    Hi ls. I managed to find some rolling resistance data on your old tires here: 2009 Rolling Resistance Efficiency Ratings for 77 Tires | The Similarly Stimulated Saturn

    According to this data, those tires are about 30% worse than the best offerings tested! That's going to be a pretty massive difference.

    The actual improvement in MPG will depend somewhat on the average speeds you drive. At lower speeds where rolling resistance can outweigh air resistance then you could get a huge gain, like 20% or so. At higher speeds where air resistance tends to dominate then the improvements mightn't be so large. Hopefully the new tires will get your fuel economy up to something close to 50 mpg. :)
     
  5. ls40095

    ls40095 Junior Member

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    I will let you know ASAP...The sooner the better :)

    Wow 65mpg like over a tankful?...What do you get now with overnight charges? Like 90mpg?
    wait until the new 2014 comes out, I heard 60mpg base!

    I cant believe you found that information..I knew they were POS tires...The car has been sitting for about a month in icy cold, could also be some frozen moisture inside the rims...I also notice a slight difference between the SOC with both cars. I think the latest Prius is a bit fresher and with the new tires, 10 aditional MPG would not surprise me, including the fact the new tires are just that., new.
     
  6. F8L

    F8L Protecting Habitat & AG Lands

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    I'd also have that 12v battery checked out. If its been sitting you don't want a weak battery in your car. :)
     
  7. bisco

    bisco cookie crumbler

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    i got 74 mpg in summer without charging. yeterday, i got 61 mpg in 14 degree weather. when you throw in a charge, it adds a whole new dimension.
     
  8. ls40095

    ls40095 Junior Member

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    Its good.. I got caught in a bad snow storm this morning on the way to get the front end aligned. I never made it cause the roads were so bad that I turned around..The POS tires did serve a purpose though, got me back home and after 40 miles watching the scanguage with the heat blowing and lights on, the 12v worked fine. Thanks

    WOW!
    The Prius is technological marvel. I was blown away when after reading about the platform and engineering. I'm going to buy either a 2010 or 2012 C this year. For some reason the C market is very soft, nobody wants them because they are so small but I like the yaris small car feel so I'm on the hunt for either.
     
  9. wek

    wek Junior Member

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    I too had a problem with big MPG drop after getting new Cooper touring tires. I went from 45-48 avg to 39-41. Can this really be the cause. My 12 volt battery is only holding 11. 5 and the dealer is saying it's fine. The fight is on with them. Any advice?
     
  10. F8L

    F8L Protecting Habitat & AG Lands

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    Yes, tires can drop you well over 4mpg and a weak 12v could as well assuming its so bad your engine is running more often than it should. 11.5v is garbage.
     
  11. ls40095

    ls40095 Junior Member

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    I expect to go from 40 to 50mpg only because I'm going from some of the worse tires to the best.
    I think 11 is a bit low, more like 12V after sitting idle or when car has been charging Voltage is up to it's normal range like 13 to 15 Volts with the car running
     
  12. bisco

    bisco cookie crumbler

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    they look great, i'm sure you'll love it, all the best!
     
  13. ls40095

    ls40095 Junior Member

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    WOW!

    Got the alignment today from a reputable Tire shop with a new Hunter machine. It looks like the Flintstones tire shop did a poor alignment and butchered the front when they put the tires on. Prior to today, the center steering was proper and the car seemed to travel straight down the road without pulling either way but the inside of the front tires are worn prematurely. The uneven wear can clearly be seen. Thats why I got it done. The attendant told me the toe and camber were out pretty bad.

    The car now goes down the road much better along with noticeably better MPG. The "crabbing" down the road that was originally thought to be solely poor tires is now a combination of poor tires and a butchered alignment.
     
  14. Norie

    Norie New Member

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    I've got Ecopia by bridgestone in Sept '12. I get as high as 56mpg every now and then...;)
     
  15. HaroldW

    HaroldW Active Member

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    Is40095
    I am glad you got the alignment as it sounded as if your old tires where cupped. Your new Michelin would have been the same in short order.:) H
     
  16. ls40095

    ls40095 Junior Member

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    Nice! I saw them too but I wanted to try the Michelin Energy Saver A/S.
     
  17. F8L

    F8L Protecting Habitat & AG Lands

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    The Energy Saver A/S is better in every way except in snow.
     
  18. ls40095

    ls40095 Junior Member

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    Tires mounted and balanced a few days ago...The softest, quietest tire ever..Better than the Michelin X tires I have on my other Prius....Its only been 2 days, 50ish miles and a bunch of cold short runs in 20 degree weather through snow, wind and slush and Im at 47.6 MPG....The car with 50k miles has a very new feel to it and Im sure with my Hypermilling driving in warm weather Im going to be pushing 60 MPG
     
  19. nh7o

    nh7o Off grid since 1980

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    What tire pressures have all your tests been done at?
     
  20. ls40095

    ls40095 Junior Member

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    40psi with the Flintstones tires and the Energy savers have the factory PSI from Costco.