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Reading tire pressures from inside my house!

Discussion in 'Model S: Driving Dynamics' started by artsci, Nov 20, 2014.

  1. artsci

    artsci Sponsor

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    I installed FoboTire today on all four wheels.

    fobotireblack.png

    This is an amazingly cool device and it make possible on-the fly readings of the pressures in each tire. In fact, I'm sitting in my house at the very moment taking readings of my Model S tire pressures, even thought the car is parked 100 feet away outside. FoboTire is a bluetooth device and comes with a smart phone app for IOS and Android. It took me about 10 minutes to install and set up. At $179.00 the peace of mind it provides is worth every penny and when I get low pressure tire warnings they'll be based on my own settings, not Tesla's. Best of all I'll know which tire is low without having to do the tire to tire shuffle required by Tesla's inadequate system.
     
  2. breser

    breser AutoPilot Nostradamus

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    But no more American Flag valve caps. :eek:
     
  3. Merrill

    Merrill Active Member

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    This looks very neat, where do you store the in car unit.
     
  4. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    What a fascinating modern world we live in.

    If I may gently ask, however, is this - remarkable, yes - product one that is a solution looking for a problem? Or perhaps it really, truly could be useful if one lived in fear of someone deflating your tires on the sly: you could catch 'em in the act.

    gotta get me some!
     
  5. AoneOne

    AoneOne Member

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    According to the user's manual, FOBO will alert when the tire pressure reaches 51 psi. With a cold temperatures of 45 psi, could 51 psi be a normal operating pressure when hot?

    Quick calculation: if the pressure absolute pressure is 45+14.7 = 60 psia and an alarm pressure of 66 psia, with pressure proportional to absolute temperature, when the absolute temperature rises to 66/60 of the cold temperature, the tire will hit the alarm. If cold is 300K, then alarm will sound at 330K, meaning a rise of 30C or 54F. A hot tire could easily be that warm, it seems.

    Do you see this as a problem?

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    Here's another brand that specs 65 psi capacity. http://us.papagoinc.com/?page_id=1492 I don't know how good it is.
     
  6. artsci

    artsci Sponsor

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    In the store space in my Evannex center console. It can be attached with Velcro pretty much anywhere.

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    I've had two instances where the Tesla system caused unnecessary problems. In both situations I had parked at the airport for a few days and found a low pressure tire warning when I returned from my travels. I then had to get out my pressure gauge and check each tire to determine which was triggering the warning, a real PIA, especially on cold evenings in the dark. With FoboTire I would have known which tire was the problem and the magnitude of the pressure shortfall.

    Plus I'm a fanatic about tire pressure. I check tire pressures every week and make sure they're to spec -- that to prevent unnecessary tire wear and keep handling at max. FoboTire will save me a lot of time, and time is money.

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    The minimum and maximum tire pressure warnings are user settable. I set my pressures at 44psi, with 51 max and 41 min, and its very cold here now. I don't think I'll exceed the 51 psi max. I don't think the tires heat up enough to add more than about 3psi, but as I can monitor this as I drive, I'll know very soon.
     
  7. bollar

    bollar Disgruntled Member

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    Neat. I ordered a set. What do you think the accuracy is?
     
  8. Kalud

    Kalud Member

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    Any impact on wheel balancing?
     
  9. swegman

    swegman Member

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    The Papago unit mentioned in post #5 above is $210 at Amazon. It appears to be a similar device, although some of the screen shots shown on the website are in a foreign language.
     
  10. shelbri

    shelbri Member

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    First - thanks for this thread as it prompted me to take a look at my tire psi. All were at 41. So it got me thinking - when does the Tesla monitoring indicate that tire pressure is low?
     
  11. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    It is amazing that Tesla deleted this feature in the S; 5 years ago, the Roadster very nicely displayed tire pressure in each tire, and still does...
     
  12. efusco

    efusco Moderator - Model S & X forums

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    Curious about that too. Have you checked accuracy with a good manual/digital gauge?
     
  13. Merrill

    Merrill Active Member

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    Can you put it in the center consol and close the covers, it would be nice to know which tire is low.
     
  14. jordanthompson

    jordanthompson 2010 2.0 Sport, VIN 0683

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    The TPMS in the Roadster is horrible! and the tires are SOOOOOO expensive! This is a wonderful solution! Now if only we could disable the car's TPMS warning :)

    I just bought a kit.
     
  15. artsci

    artsci Sponsor

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    #15 artsci, Nov 21, 2014
    Last edited: Nov 21, 2014
    FYI the tire pressures I'm reading inside the house are the last pressures when I left the car. The app remembers the pressures, but unless you're within Bluetooth range it does not update them.

    Will be checking that with an accurate gauge this weekend.

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    Yes, that's what I do.

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    None, it's too light to make any difference.

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    I'll be finding a source for flag decals that I can place on top of the Fobo sensors. or maybe ones with the Tesla logo.

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    On my 15 mile drive this morning the tires gained only 2 lbs of pressure. It was about 28 degrees outside when I started the drive. The Fobo also gives a read out of tire temperature. Mine were 28 degrees when I started and about 45 degrees when the drive ended.
     
  16. artsci

    artsci Sponsor

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    Here's a screen shot of the iPhone app at the end of my drive this morning.

    IMG_0084.PNG
     
  17. swegman

    swegman Member

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    The Papago unit indicates the accuracy is within 1 psi. I would think the accuracy of the Fobo unit would be comparable.
     
  18. AoneOne

    AoneOne Member

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    Comparing today's result to theory:

    predicted change of pressure = (change in temp)/(absolute temp)*(absolute pressure)

    = (45 - 28) / (460 + 28) * (45 + 15)
    = 2.1 psi

    Close enough. If the tires hit ~60F above ambient you'll reach 51 psi. It seems possible:

    A Look Behind the Tire Hysteria - Column - Car Reviews - Car and Driver says "Typical tires experience a temperature increase of roughly 50 degrees after running on the highway for a half-hour."

    That said, if it only happens rarely, and the warning isn't too annoying, it could be ignored.
     
  19. Merrill

    Merrill Active Member

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    Does this app work on an iPad?
     
  20. Andyw2100

    Andyw2100 Well-Known Member

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    I may order one of these Fobo units once I have my P85D, but in the meantime, since it was just brought up, would anyone care to recommend a good digital tire pressure gauge? If the recommended gauge happened to be available on Amazon, even better!

    Thanks!
     

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