Tire pressure gauge not working with spare tire

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by whataboutbob, Nov 29, 2022.

Page 2 of 2
  1. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,379
    4,162
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    What country is your tire gauge pressure made from?
     
    #21 Grit, Dec 4, 2022
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    26,039
    17,010
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Lots of tire pressure gauges are not exactly lab-grade instruments.
     
    #22 ChapmanF, Dec 4, 2022
  3. whataboutbob

    whataboutbob Junior Member

    Joined:
    Jan 1, 2014
    74
    16
    0
    Vehicle:
    2010 Prius
    Model:
    IV
    Like many products these days, it's Made in China and it appears to be a quality product, so I am not faulting it for that.
     
    #23 whataboutbob, Dec 4, 2022
  4. whataboutbob

    whataboutbob Junior Member

    Joined:
    Jan 1, 2014
    74
    16
    0
    Vehicle:
    2010 Prius
    Model:
    IV
    Well according to the manufacturer, the gauge is "performance tested, certified, & calibrated accurate within ANSI Standards (±1.5%) at our ANSI accredited calibration facility, ensuring precise tire pressure readings without relying on batteries". I have sent them an email to inquire.

     
    #24 whataboutbob, Dec 4, 2022
  5. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,558
    10,334
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Looking closer that the picture, I think it starts at 5 psi, not 0 The smallest printed number is 10, and there are only 5 ticks below that:

    upload_2022-12-4_13-10-40.png

    So if your spare tire had just 5 psi, or even 6.5, then the gauge wasn't "out of spec". And if that "spec" is like some other devices I have used and received actual calibration certificates for, it is calibrated at only one point, somewhere near the middle of scale, not over the full range.
     
    #25 fuzzy1, Dec 4, 2022
    jzchen, CR94 and whataboutbob like this.
  6. whataboutbob

    whataboutbob Junior Member

    Joined:
    Jan 1, 2014
    74
    16
    0
    Vehicle:
    2010 Prius
    Model:
    IV
    Good catch! I think you are right, so technically, it's possible that it's below that threshold. On a side note, a (almost) flat spare tire feels a lot firmer than a regular tire, so that threw me off too. Have to admit that a spare tire is one of those things that most people don't pay any attention to until they need it at which time it is usually at an inconvenient time and place. I will make sure to check the pressure annually to keep it inflated.
     
    #26 whataboutbob, Dec 4, 2022
  7. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    9,322
    5,685
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three


    Seems to be a clear case of operator error
     
    #27 rjparker, Dec 4, 2022
  8. whataboutbob

    whataboutbob Junior Member

    Joined:
    Jan 1, 2014
    74
    16
    0
    Vehicle:
    2010 Prius
    Model:
    IV
    In my defense, the spare tire looks and feels deceptively fuller than it is, you can see a pic in one of comment, in fact, there was hardly any give when I pressed on it. When my regular tire is flat, it looks like flat.
     
    #28 whataboutbob, Dec 4, 2022
    bisco likes this.
  9. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,637
    50,841
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    you're welcome :p
     
    #29 bisco, Dec 4, 2022
    Grit, Mendel Leisk and whataboutbob like this.
  10. CR94

    CR94 Senior Member

    Joined:
    Dec 2, 2014
    2,660
    1,148
    0
    Location:
    Northwestern S.C.
    Vehicle:
    2011 Prius
    Model:
    Two
    Exactly as I suggested back in post #15.

    FYI, cheap dial gauges generally tend to be less reliable than cheap pencil-style tire-pressure gauges. I've tested them.
     
    #30 CR94, Dec 4, 2022
    Grit likes this.
  11. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    9,322
    5,685
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    A flat tire holding up a 3500 pound car will look it
     
    #31 rjparker, Dec 4, 2022
  12. whataboutbob

    whataboutbob Junior Member

    Joined:
    Jan 1, 2014
    74
    16
    0
    Vehicle:
    2010 Prius
    Model:
    IV
    This feels like a solid product but what I didn't know and wasn't documented, more like no documentation, is that it has a minimum threshold before registering. What that threshold is, I am trying to find out now.
     
    #32 whataboutbob, Dec 4, 2022
  13. whataboutbob

    whataboutbob Junior Member

    Joined:
    Jan 1, 2014
    74
    16
    0
    Vehicle:
    2010 Prius
    Model:
    IV
    I never put-on the spare after I got a regular flat tire and had it towed, and good thing I did because even though it didn't look like it, the spare tire is pretty low too.
     
    #33 whataboutbob, Dec 4, 2022
  14. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    17,558
    10,334
    90
    Location:
    Western Washington
    Vehicle:
    Other Hybrid
    Model:
    N/A
    That is why it is good have a tire pump in the car's emergency kit. If the spare is too low, then it can be pumped up.
     
    #34 fuzzy1, Dec 4, 2022
    Mendel Leisk likes this.
  15. CR94

    CR94 Senior Member

    Joined:
    Dec 2, 2014
    2,660
    1,148
    0
    Location:
    Northwestern S.C.
    Vehicle:
    2011 Prius
    Model:
    Two
    As fuzzy1 pointed out, the photo shows the minimum threshold is supposedly 5 psi. The real reason cheap dial pressure gauges have a protruding pin (which we can see in the photo) to block the pointer from rotating beyond a certain point is to hide the fact that if the scale were extended to "0," and if the pointer were not blocked, it still probably wouldn't stop exactly at "0." Such an obvious error would lead to complaints and product returns.
     
    #35 CR94, Dec 4, 2022
  16. Siward

    Siward Active Member

    Joined:
    Aug 7, 2014
    311
    126
    10
    Location:
    Toronto
    Vehicle:
    2012 Prius
    Model:
    Three
    I had the exact same thing happen to me.

    One of my tires had a flat about 3 years ago, so I got it replaced at some cheap tire shop. They replaced the tire valve. After the replacement, my tire gauge no longer worked with the new tire. What was weird as the new tire worked with my other tire gauge (I had two digital tire gauges. One worked, one did not). I also have a tire inflator with a gauge and worked fine too.

    In the end, it is caused by either a cheap tire gauge that doesn't push in far enough or it is a cheap tire valve with a not so good nozzle. I didn't have any tire gauge problems with valves from my Toyota Dealership or from the reputable tire shop I normally go to. The more expensive tire gauges all worked.
     
    #36 Siward, Dec 5, 2022
    jzchen likes this.
  17. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    26,039
    17,010
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    If you had the exact same thing happen to you, that means you used a tire gauge with a minimum reading of 5 psi on a spare tire that was inflated too low to move it.
     
    #37 ChapmanF, Dec 5, 2022
  18. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,637
    50,841
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    maybe op needs to rethink this
     
    #38 bisco, Dec 5, 2022
  19. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    26,039
    17,010
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    i think op's got it sorted
     
    #39 ChapmanF, Dec 5, 2022
    fuzzy1 likes this.
(You must log in or sign up to post here.)
Page 2 of 2