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Let's talk tire pressure...

Discussion in 'Gen 3 Prius Main Forum' started by socal13, Aug 2, 2013.

  1. socal13

    socal13 livin in the foothills...

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    What kind of tires do you have and what pressure are you currently using? I have 17" Toyo Proxes with 40 fr/39 r. I was at a Toyota dealer yesterday and the salesman (says he was a tech) says to use the recommended pressure inside the door (33f/32r for my tires.) Any thoughts? Would like to hear other opinions. Thanks.
     
  2. tach18k

    tach18k Member

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    I know many sales/tech guys that I had to walk them through my repairs, just saying...
     
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  3. socal13

    socal13 livin in the foothills...

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    I know what you mean... One sales guy didn't know what a Persona was.

    I know psi is a balance between tire wear life, comfort, handling, fuel economy, safety. I think the posted tire pressure on the door is way too low from what I have read.
     
  4. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    If you were that worried about fuel efficiency, you'd be rolling 15s, so I think I'd club up to the low 40's and see if that changes things for you in terms of FE versus ride. I use 42/40, but I prefer a stiffer ride that most.
    I'd recommend against going above the max sidewall pressure embossed on the side of the tire for all the obvious reasons and besides.....even if your tires are stiff enough for you to run over a dime and be able to tell whether it's heads or tails, that's not going to buy you much in the way additional fuel efficiency.

    Oh yeah.
    If you're one of those people who roll on nitrogenated tires...PLEASE at least consider replacing the lime-green valve stem caps with black ones.
    I drive a Prius too, and I hate to see people perpetuating poor stereotypes..... Just sayin' :)
     
  5. bisco

    bisco cookie crumbler

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    wouldn't be kosher for them to tell you anything but sop.;)
     
  6. g4_power

    g4_power Junior Member

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    I always go by what's on the tires. My tires indicate 44 psi max, so I have mine at 40 psi which is about 10% below the max.
     
  7. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    I'm running 38/37 on my Toyo's. I was thinking about going up to 40/39, but was a little concerned. Anyone running higher than 38/37 on Toyo's?

    Oh, yeah... Don't listen to the sales/tech guy. He's probably the same one that tried to discourage me from changing my transaxle oil!
     
  8. mmmodem

    mmmodem Senior Taste Tester

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    The Toyota dealer has to walk the company line. If he were to say something other than Toyota recommended, then he would be liable for any damages. It's like asking a mom if they she has a good kid. There's only answer to that question.
     
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  9. socal13

    socal13 livin in the foothills...

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    I'm running 40/39 on my Toyos... hoping this is a good balance between tire life and mpg.
     
  10. harold

    harold Member

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    I'd imagine if the recommendation is 32/33, there's a reason they came to those numbers ?

    My car came with nitro fill, first thing. Did was to replace the green caps.
     
  11. pauln64

    pauln64 Junior Member

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    I run 37 all around for mine
     
  12. bisco

    bisco cookie crumbler

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    factory spec is a balance of many things like mpg's, handling, noise, traction, longevity, etc. it's a recommendation, not written in stone, just inscribed in metal on the pillar.:cool:
     
  13. Drdiesel

    Drdiesel Active Member

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    185/65/15 Kumho KH30 EcoWing tires on a 6.5 inch aftermarket wheel. I run 42 in all 4.
    I ran 42 in the stock tires too. The wider the tire, the more you'll get center wear at higher pressures.
     
  14. cary1952

    cary1952 Member

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    i was running 42/40 on my stock 15 bridgestone ecopio ep20 , but they were too harsh, so I dropped down to 40/38 and it is much better, with probably no noticable loss of mpg.
     
  15. retired4999

    retired4999 Prius driver since 2005

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    42 front 40 rear
     
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    boppo Active Member

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  17. jaymac

    jaymac membore

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    42/40 is my sweet spot too.
     
  18. tumbleweed

    tumbleweed Senior Member

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    I am using Michelin Primacy MXM4 215/45-17, 40 psi front and rear. The Michelin "Owner's Manual" that comes with the tires says to use the manufacturer's recommended pressure as a minimum and the maximum load pressure on the sidewall as a maximum. That gives plenty of range to find pressures that suit your driving style and road conditions.

    There is no one best set of pressures that work for everyone in all conditions, it's something you need to find on your own through experimentation.
     
  19. mmmodem

    mmmodem Senior Taste Tester

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    In general, higher PSI tires mean better fuel economy, louder tires, and less comfortable ride. Not always but in general. Some of us prefer comfort and some of us prefer economy. Toyota recommends a balance of the two. Safety-wise, it's clearly printed on the Ecopia EP20 tires that came with my car can handle a max of 44 PSI.
     
  20. Jonny Zero

    Jonny Zero Giggidy

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    Does anyone run a side to side bias to compensate for side to side weight distribution differences?