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Will 50 psi tire cause any problems with my car?

Discussion in 'Gen 4 Prius Main Forum' started by rlecastro7, Jul 7, 2018.

  1. fuzzy1

    fuzzy1 Senior Member

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    There was probably more damage to your dental work, rattling any fillings and crowns, than to the car or tires. :)

    There have been concerns raised here about faster wear of bearings and suspension components from the harsher ride and increased rattling, but so far no real evidence for or against. It remains an open, unresolved question.

    As Mendel pointed out, the higher pressure is just for shipping. I seem to remember that it reduces flat-spotting while the car is parked and chained down for two months for its trans-oceanic cruise.
     
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    That's not far off; maybe due to some elapse of time, or your gauge might be off. With the 15" tires, it's just slightly low, at any rate.

    upload_2018-7-8_5-18-24.png
    (17" are 33/32 front/rear)

    Amen. Hey just for giggles: check the spare pressure.
     
  3. Starship16

    Starship16 Senior Member

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    I keep telling myself to go check the spare tire psi..... It's been 31 months! :ROFLMAO:
     
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  4. alanclarkeau

    alanclarkeau Senior Member

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    I thought I'd read somewhere that the Tyre Pressure Monitoring System only alerted to Under-inflation.

    I checked WIKI - and it seems to agree that it's a "low-pressure warning" ... "The target of a TPMS is avoiding traffic accidents, poor fuel economy, and increased tire wear due to under-inflated tires through early recognition of a hazardous state of the tires."

    I checked the USA PRIUS Manual which tends to agree - though, it's not a technical Manual:
    upload_2018-7-8_22-37-3.png

    They would have checked it (hopefully) at service.

    Oh - and I wouldn't worry one bit. I would double check how accurate your gauge is too. But I've read on PriusChat comments by PRIUS owners who have run those sorts of pressure their whole car's life. Maybe if it was like that for 170,000km you could find that maybe some bushes etc might be being chopped out, but they're designed for higher pressures.

    My FORD FOCUS had the same P195/65-R15 sized tyres. It had quite a few tyre pressures listed - starting with 31Front/33Rear - going up to 38F/44R with high speed, full load.
     
    #24 alanclarkeau, Jul 8, 2018
    Last edited by a moderator: Jul 8, 2018
  5. Lucifer

    Lucifer Senior Member

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    50 each as stated is shipping pressure, meaning the set up tech at your dealer failed:)
    I like to run the rear tires a few pounds below the front tires.
    The TPMS only dings when one or more tires run below it’s threashold amount.
    The pressure on the sidewall is 1/2 the bursting pressure of that tire.
     
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  6. padroo

    padroo Senior Member

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    If I remember right the TPMS will not turn on until the mid twenties psi.
     
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  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Yeah I believe TPMS only alerts to low pressure, and it's something like a 25% drop needed?

    OTOH, ours went off once, for no good reason, pressures were fine, and when I bumped them up 4~5 pounds, the light went out. Never happened again.

    When I checked our spare's pressure, soon after purchase, it was around 40 psi (should be 60), not too impressed with that. The car's build-date was about 15 months back.
     
    #27 Mendel Leisk, Jul 8, 2018
    Last edited: Jul 8, 2018
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  8. wjtracy

    wjtracy Senior Member

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    I believe Gen2 TPMS default alarm is set at 26 psia. Supposedly by pressing the RESET button, you can reset this alarm to a higher level, but I have not verified that in my car.

    I finally lost my second TPMS at 12-years. Two OEM still working.
     
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  9. ChapmanF

    ChapmanF Senior Member

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    You can see what the current threshold is easily enough using Techstream. You can only change it by changing the tire pressures and pushing the magic button. If you push the button with the tires at 44 psig, the threshold ends up around 34.1, or at least mine did.

    -Chap
     
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  10. Munpot42

    Munpot42 Senior Member

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    I checked my spare tire pressure once about a year ago, had to take the spare out of the trunk as the valve was facing the trunk floor. It was 15psi low, maybe next year I'll wrestle the spare out again.
     
  11. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Just thank God it's not one of those truck-style, slung under the vehicle.
     
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  12. padroo

    padroo Senior Member

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    I have never checked my spare in my 06 Dakota come to think of it.
     
  13. Starship16

    Starship16 Senior Member

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    Two things I don't believe about dealers:

    1) I think that "126 Point Certified Inspection", when they inspect a used car prior to sale, is a bunch of baloney. Hope I'm wrong. And they probably just rush thru the new car inspection too. Skimp over stuff.

    2) They don't even check the few items on the inspection sheet when I go in for routine service. At my dealer, I can sit nearby and watch them. No headlights check. No tail lights or brake lights check. No suspension check or tightening of bolts. No 12V battery check. Washer fluid never refilled. Tire pressure is never right. Just a real fast cursory glance at the brakes while rotating the tires, etc, etc. But when you get your car back, 20 items are checked off on the sheet! :ROFLMAO: I had a brake light out on my Camry for months... and they never mentioned it.

    Did no good to complain.
     
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  14. Starship16

    Starship16 Senior Member

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    Alan, you mentioned tire guages. I've tried 3 brand new ones on the same day. And they all showed a different PSI for the same tire. It's a guessing game.
     
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  15. Fester

    Fester Active Member

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    At that kind of over-inflation You'll have a much harsher ride of course and despite the shock absorbers, more vibration is going to be transmitted to the car frame which will tend to loosen interior components up and contribute to all those funny buzzes and rattles as the car ages to become even worse...
    There's a safety issue too, since if the tire pressures are at 50psi "cold", then running with hot weather and running a high speeds, you could actually blow a tire.
    Lastly, over-inflation can change the wear pattern of your tires treads causing the center treads to wear faster. Under-inflation can cause the outer treads to wear faster.
     
  16. William Redoubt

    William Redoubt Senior Member

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    The TPMS in a Prius measures pressure differential, not pressure itself. You need a third party system to monitor the actual pressure. The way the TPMS works is that you will get a warning light if the the difference in the pressure between the four tires is significant. A low or over inflated tire is then an investigatory process to locate.
     
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  17. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Lemmee guess, it's underslung? Those are a pain. No fun getting them off, and then, you get to put it back on, with gravity fighting you.
     
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  18. Lucifer

    Lucifer Senior Member

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    People that buy used tires shouldn’t, people that want the best mpg’s, the safest most controlled ride should, the car stops faster, turns more precisely, wobbles around less, it’s not like fire, the tires don’t keep heating, at highway speeds the tires may increase a pound or two in pressure.
     
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  19. fuzzy1

    fuzzy1 Senior Member

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    It seems that for common quality tires, there is still plenty of margin to burst pressure. At least, we don't hear of this happening the way we heard about Ford Explorers with underinflated and mis-built Firestone tires bursting in hot weather at high speeds, causing a large number of fatal rollovers a couple decades ago.
    For passenger car tires, steel belted radial construction has pretty much cured this one. The steel belts don't allow the tire to 'balloon' in the center the way old fashioned bias ply tires did.
     
    #39 fuzzy1, Jul 8, 2018
    Last edited: Jul 9, 2018
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  20. ChapmanF

    ChapmanF Senior Member

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    On the contrary, the Prius TPMS measures the pressure itself, and the temperature, individually for each tire, and has an individual actual-pressure low-alarm threshold for each tire (though the only way you can set these thresholds is by airing the tires to whatever pressure you choose and then pressing a single button that sets each tire's threshold to a certain fraction below it's current pressure). All of these values are easily viewed in Techstream. A ScanGauge II with recent-enough firmware can also show them.

    The values are shown in Techstream listed by the ID number of each transmitter. As long as you keep track of which transmitter is in which tire (and follow the shell game when tires get rotated), the only investigation you need to do when the warning light comes on is to view the readings, and add air to the tire that's low.

    -Chap
     
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