Tire pressure gauge not working with spare tire

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

  1. Grit

    Grit Senior Member

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    What country is your tire gauge pressure made from?
     
  2. ChapmanF

    ChapmanF Senior Member

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    Lots of tire pressure gauges are not exactly lab-grade instruments.
     
  3. whataboutbob

    whataboutbob Junior Member

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    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.
     
  4. whataboutbob

    whataboutbob Junior Member

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    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.

     
  5. fuzzy1

    fuzzy1 Senior Member

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    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.
     
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  6. whataboutbob

    whataboutbob Junior Member

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    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.
     
  7. rjparker

    rjparker Tu Humilde Sirviente

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    Seems to be a clear case of operator error
     
  8. whataboutbob

    whataboutbob Junior Member

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    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.
     
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  9. bisco

    bisco cookie crumbler

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    you're welcome :p
     
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  10. CR94

    CR94 Senior Member

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    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.
     
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  11. rjparker

    rjparker Tu Humilde Sirviente

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    A flat tire holding up a 3500 pound car will look it
     
  12. whataboutbob

    whataboutbob Junior Member

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    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.
     
  13. whataboutbob

    whataboutbob Junior Member

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    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.
     
  14. fuzzy1

    fuzzy1 Senior Member

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    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.
     
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  15. CR94

    CR94 Senior Member

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    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.
     
  16. Siward

    Siward Active Member

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    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.
     
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  17. ChapmanF

    ChapmanF Senior Member

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    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.
     
  18. bisco

    bisco cookie crumbler

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    maybe op needs to rethink this
     
  19. ChapmanF

    ChapmanF Senior Member

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    i think op's got it sorted
     
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