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New Tires = Lower MPG???? Help!!

Discussion in 'Gen 2 Prius Fuel Economy' started by s.e.tx_parrothead, Jun 10, 2007.

  1. s.e.tx_parrothead

    s.e.tx_parrothead New Member

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    Got new tires on Maggie about 3 weeks ago. On the way to the dealership was getting 51 mpg and after getting Maggie's "New Shoes" the MPG started going down hill. On the way home, was struggling to get 45-46mpg. Don't know if this is normal or not, but after 3 tanks of gas, I am still averaging about 45-46. With the old tires, I was averaging around 49-50. I live about an hour north of Houston and I have had to run the A/C due to the high humidity but I run it just enough to cool down the cabin and then I turn it on to a lower fan speed. I have the temp set to about 77 degrees which is comfortable for me (little warm for the hubby).

    I put the same ole Goodyears back on the car since I have the Extra Mile pkg. I am not sure if they did an alignment or not but I did check the air pressure about a week after the install and three tires were at 33 and one was at 30. I bumped the front two to 39 psi and the back two to 37 psi. If I fill up the car on the way home and check the mpg when I pull in the drive way, it is back up to the high 40s but as the week/tank wears on it drops. I drive the speed limit or a mile or two over (do use the cruise) and the commute is rather hilly.

    I am at wits end wondering if just the A/C running a bit more caused the drop or what happened. Any suggestions????? Oh, have just under 32,000 miles on the car. Got the oil changed about 3 days prior to getting the new tires. Haven't done the officially sanctioned Toyota 30, 000 mile service at this time.

    Thanks-
    Kris
     
    #1 s.e.tx_parrothead, Jun 10, 2007
  2. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    There have been reports of new tires lowering mileage. Since I haven't changed tires, I don't know directly.

    About the tank/week wearing on and the mileage dropping, as goofy as it sounds I truly believe that when I'm super-sensitive about mileage I actually hinder my own mileage by worrying more about it and working too hard at it. Sounds silly, I know.

    About the A/C, because it is not hooked mechanically to the engine, it doesn't draw directly from it. However, running the A/C does draw from the battery which will reduce the State of Charge and may cause the engine to run more to recharge it and limit your stealthing distance.
     
    #2 TonyPSchaefer, Jun 10, 2007
  3. Rangerdavid

    Rangerdavid Senior Member

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    Hi Kris:

    I remember reading several posts on here in the last year about new tires, and the reduced mileage until the "new" wears off the tires and they are broken in a bit. I'll look and see if I can add a link to one of the posts for you, but all else being equal, sounds like its just new tires and that should change after you get 2500 - 5000 miles on the new tires.

    Good luck, and I like your avitar, Buffett rules !! :lol:
     
    #3 Rangerdavid, Jun 10, 2007
  4. jamesl

    jamesl New Member

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    Kris you didn't say what was the brand and type of tire you put on that is getting the lower mpg....
     
    #4 jamesl, Jun 11, 2007
  5. s.e.tx_parrothead

    s.e.tx_parrothead New Member

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    I guess I just need to be patient...Not real good at that :rolleyes: I will forget about it and see what happens after the 35000 mile oil change. I know that as soon as the Extra Mile pkg is up, I am probably going with something other than the OEM Goodyears.

    RangerDavid, glad you liked the avitar. It is off a Caribbean Soul T-Shirt. We were lucky that JB made it to Houston for the Bama Breeze tour. He opened the tour there at Minute Maid. It was good, but I miss the smaller venues...The acoustics are better. But oh well it is JB!!!!! B)

    Thanks again!
    Kris
     
    #5 s.e.tx_parrothead, Jun 12, 2007
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