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TPMS sensitivity to cold weather

Discussion in 'Model S: Driving Dynamics' started by blanche, Oct 3, 2015.

  1. blanche

    blanche Member

    Joined:
    Jun 30, 2015
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    100
    Location:
    Leesburg, Virginia
    With fall almost upon us, we are starting to get a few days where the daytime temperature goes from a regular high in the 70s to a high of 50. On every one of these days with a wild swing, the TPMS warning for low pressure goes off. Every time it is a different or multiple tires. It turns out that a pressure drop of about 2psi (38psi down from 40) seems to be enough to trigger a low pressure warning on the dash.

    Until v7 comes out with a app for tire pressure, I'm forced to check the pressure on each tire to make sure that this is not a flat tire and I have enough pressure to get home where I can top it off.

    Is this a common occurrence with everyone and is there a known threshold for pressure sensitivity for the low pressure sign to come on?
     
  2. CHG-ON

    CHG-ON Still in love after all these miles

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    Santa Cruz Mountains, USA
    Mine don't go off until the tire tire is almost empty. Very annoying.
     
  3. cinergi

    cinergi Active Member

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    Fill to 42 (the recommended pressure) at 70F and after it's been at least an hour since driving and you should be OK until it gets significantly colder.
     
  4. FlatSix911

    FlatSix911 918 Hybrid

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    A quick rule of thumb ... 1 psi drop for a 10'F temperature drop.
    You may want to adjust your cold tire pressure for Winter temps.
     
  5. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Location:
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    As temperatures drop tire pressure lowers. Don't concern yourself with the daily highs, just check and adjust the pressure before you drive after a temperature drop. If the TPMS is alerting, the pressure is way too low and probably has been for some time because the TPMS' threshold is not a "safe pressure" threshold, it's an "uh oh" threshold.

    Ideally, you never want to the pressure to drop even one psi below the vehicle placard pressure. The vehicle placard pressure is not an upper limit, it's just a suggestion based on average** conditions and needs to be adjusted for individual locations and conditions, in most cases should be viewed as the pressure you never want to go below.

    ** If your head is in the oven and your feet in the freezer, your privy members are average.
     
  6. Dbitter1

    Dbitter1 Journeyman Member

    Joined:
    Dec 12, 2014
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    201
    Location:
    Chicago, IL
    I have 19's, and have never had them alarm (or deflate), even when I had a nail clean through one. (FTR: Ouch, $~400 with install at my SC). Probably hit -10F or so last winter, narry a peep about the tire pressure. I'd make sure you don't have a leak or bad seal or something.
     

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