Low Tire Pressure Light On

Discussion in 'Clarity' started by Raymondca, Jan 18, 2021.

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  1. Raymondca

    Raymondca Member

    The low tire pressure light was on. I checked and all four tires reported 31 PSI. I didn't think there was a leak so I recalibrated the TPMS to remove the warning both on my dashboard and my app. The driver door jam says 36 PSI. Is 31 PSI also ok in cold weather? Just want to be sure.
     
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  3. 36psi is the recommended, minimum, pressure for the vehicle at GVWR, which is approximately 5000lbs. “Cold” is ambient temperature in the morning, having not driven the vehicle and before any tires have been exposed to direct sunlight. Cold could be 20F or 80F.

    Personally, I won’t run them below 32psi.

    The tire pressure warning system has been know to send false alarms.
     
    JFon101231 likes this.
  4. DaleL

    DaleL Active Member

    Adjust all the tires to the correct pressure, 36 psi, plus or minus about 1 psi. Then recalibrate the TPMS. 31 psi is almost 20% lower than the recommended pressure. Low pressure will reduce mpg/EV range.

    As Landshark wrote, the pressure should be inflated/set before the vehicle is driven and in the morning before the sun hits the tires.
     
  5. Raymondca

    Raymondca Member

    Thank you. I will check again. Maybe it's my gauge. The chance of all four tires dropping to the same number is low. About recalibrating TPMS, what does it mean? If my tire pressure is low for real, say 31. Does recalibrating TPMS makes the computer simply accept the 31 as normal. Or the light will turn on again if it's far from the recommended range?
     
  6. Tires lose pressure over time. If it had been 3-6 months since you last checked, and if you inflated them to 36psi at 75F and it is now 25F, that could explain why they are all 31psi. The system in the Clarity does not actually measure air pressure. It measures a difference in rotational speed between the tires. My understanding of how it works, is that all the tires could be low, and the system would not alert you since they would all be rotating at the same speed.

    The warning in my car went off when all the tires were at 34-35psi. I dislike this feature very much.

    As mentioned, set them to 36psi to recalibrate. I carry 3 gauges, a stick style, an analog and a digital. All 3 read the same, so I’ve concluded that they are all accurate enough for my purposes. Alternatively, you can compare your gauge(s) to a master gauge at a tire shop and note any difference, 1-2psi low, for instance. Or, carry your own master gauge which is only used as a baseline to measure your other gauges.
     
    DaleL likes this.
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  8. PHEVDave

    PHEVDave Active Member

    This is normal behavior when the weather changes. Here in the Midwest I can expect all tires to be low when cold weather sets in. Conversely, in the spring when things warm up, it will make tire pressures go up.
     
  9. It’s not just normal behavior, it’s the law.
     
    PHEVDave likes this.
  10. Paul K

    Paul K Active Member

    This is completely normal when extreme cold sets in. I top my Leaf's tires up with a bicycle pump when things turn really cold. Winter tires have more rolling resistance than the stock tires as is. Underinflation due to cold temps makes it even worse.
     
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  12. DaleL

    DaleL Active Member

    On the issue of tire pressure, there is the air versus pure nitrogen debate. Dry air, by volume, is a mix of nitrogen (78%), oxygen (20.9%), argon (0.9%), carbon dioxide (0.3%) and other gasses. However, a home air compressor does not remove the water vapor which also is present. Oxygen reacts with the materials on the inside of the tire and is gradually used up. This reduces the pressure in the tire. Water vapor has a much lower molecular weight (18) and leaks out faster than the other gasses. (nitrogen 28, oxygen 32, argon 40, CO2 44) Because of the water vapor and oxygen, tires inflated with regular air will lose pressure over time more rapidly than those inflated with pure dry nitrogen.

    Even though pure nitrogen is superior to plain old air, air is free. I recommend checking all tires every couple of weeks and adjusting the pressure as needed. All the tires on a vehicle should lose (most common) or gain pressure in common.
     
  13. Alex800st

    Alex800st Active Member

    If nitrogen is the slowest leaking gas that means over time it will be almost the only one in the tire, if I occasionally top it up with regular air )
     
    insightman likes this.
  14. Moisture in compressed air can be easily minimized. If you own a compressor with a receiver tank, drain it periodically. Moisture collects inside the tank as condensate and will end up at the bottom of the tank as a puddle of water. Secondly, add a water separator filter to the air line.

    The filter may be overkill for inflating tires. I happen to have one for use with pneumatic tools on my shop compressor.
     
  15. Alex800st

    Alex800st Active Member

    For my Clarity I trust only Honda’s original, imported from Japan compressed air. Not cheap, but anything less will negatively affect Clarity’s performance and drop mpg.
     
  16. You really should try some Algerian Helium. It makes the car almost 200lbs lighter without all that heavy, moisture laden compressed air in the tires. Just remember to check the pressure more frequently than with air or nitrogen, those tiny molecules can sneak out before you know it.
     
  17. Boston_Pilot

    Boston_Pilot Active Member

    Day Drinker eh?
     
  18. Negative. Don’t twist your ankle jumping to conclusions. Just contributing to the absurdity of the Japanese air preference
     
  19. Boston_Pilot

    Boston_Pilot Active Member

    Sorry, I missed the Oregon part.
     
    Pooky likes this.
  20. You’re 0 for 2. It must be a gift.
     
  21. Boston_Pilot

    Boston_Pilot Active Member

    Oh, I dunno. It’s pretty easy to spot. Not so much a gift.
     
  22. East to ignore as well. See ya.
     

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