Tire pressure keeps going down, but

Discussion in 'Indian Motorcycle Tech Questions & Answers' started by wildmandmc, Dec 22, 2019.

  1. wildmandmc

    wildmandmc Well-Known Member

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    When it's cold well below 60 rear tire pressure goes down, sometimes to about 37, slowly for days will go down to 33ish. pump it back up an ok. stays at 41 for weeks an even months. until next cold snap. then repeats.
    Had a flat dealer replaced rear tire. PSI stood at 42 for months until it got cold 59. went to 36. daily it slowly went down to 32. I understand cold brings it down an heat brings it up. but this gets me wtf.

    One question, on replacement wonder if dealer replaced valve? But if valve was leaking you would think in a few days/weeks it would go down (from cold start) from 42 to ??.
     
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  2. Rocko

    Rocko Well-Known Member
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    I have the same thing going on with my '18 RM. Eventually it gets up to around 40psi after riding for awhile.For me, I found that while it's low,it wears on the outer edges of the tire that wouldn't normally see wear during straight ahead riding.I'm sure there's something going on besides the cold dropping the pressure, but I'm not seeing any unusual tire wear as of yet,and it seems to reverse the effects in the summer.
     
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  3. wildmandmc

    wildmandmc Well-Known Member

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    Rocko. I also got 18 RM.
     
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  4. Rocko

    Rocko Well-Known Member
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    I guess we could always keep a small 12v air pump in the bag to keep it up. Hard to find a station anymore that has air without paying for it.:(
     
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  5. wildmandmc

    wildmandmc Well-Known Member

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    Around where i live we have WaWa. Free air. or BJ's warehouse.
     
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  6. IROQUOIS

    IROQUOIS Gold Member

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    Beyond my pay grade but I'm sure it has to do to the density of cold air vs warm air.
    I go through this with my cages, bike, tractor especially during the transition from Winter to Spring and Summer to Fall.
     
  7. PileOParts

    PileOParts Silver Member

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    I suspect it's more than just lower ambient air temperature, but I have no idea what. Since a soft tire generates more heat than a hard one, eventually the tire pressure should come up fairly close to spec if it hasn't dropped too much -- but I too have been puzzled by mysterious low pressures particularly in the rear tire of my '16 RM, with an OEM Dunlop replacement, fairly newly installed. What if the rim shrinks .0000000001" more than the tire does?
     
  8. Drifter

    Drifter Active Member

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    Tire pressure varies with temp and altitude, Boyle's Law,
     
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  9. Notaharley

    Notaharley Well-Known Member

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    Air pressure drops with the temps.
    SOME of this "air" works its way through the "rubber" (it's not really rubber).

    The nitrogen stays behind.

    You WILL lose some air as this system stabilizes in the tire.

    During this season, the temps fluctuate wildly, so air pressure fluctuates.

    I do not check my air pressure in the morning when it is 28 degrees. I check it when I'm going for a ride when it's 50.

    Before TPMS, no one knew or cared or worried. Now, with a digital readout everyone over thinks it.

    Tires are made to withstand a wide range of pressures.
    Check pressure before a ride.
    Don't worry about it until next ride.
     
  10. Baldhead_J

    Baldhead_J Gold Member
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    [​IMG]
     
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  11. Baldhead_J

    Baldhead_J Gold Member
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    Another great response Boyles down to another meme:

    [​IMG]

    It's Memeville, I know he's not really a scientist.
     
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  12. Notaharley

    Notaharley Well-Known Member

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    Hahahha.....

    You got the same sense of humor as my daughter!
     
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  13. thumper

    thumper Gold Member
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    I have seen alloy wheels with a hairline crack which allowed air to escape when I was mechanic.
     
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  14. Notaharley

    Notaharley Well-Known Member

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    I've seen kids put pebbles in the valve cap....

    Once a mechanic, always a mechanic :)
    I owned a shop....many years ago. Miss it. Never made much money, but had fun.
     
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  15. IROQUOIS

    IROQUOIS Gold Member

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    It's a good rule to keep them close to recommended pressure.
    I've had tires explode do to improper TP on tractor trailers and it rivals a canon! Shrapnel flying everywhere. The traffic around you fade away quickly....gives you all the room you want/need......lol.
    I was pulling a set of doubles and lost a tire on the tow dolly between the trailers. Did that make things squirrelly. Just ask Bill Nye the science Guy.:eek: Ive had it happen in cold and hot weather.
     
    #15 IROQUOIS, Dec 22, 2019
    Last edited: Dec 22, 2019
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  16. PileOParts

    PileOParts Silver Member

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    Hey, Thump -- did the air escape when you weren't a mechanic ? ? ? ? ?
     
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  17. Baldhead_J

    Baldhead_J Gold Member
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    I'm so sorry for you.
     
  18. PileOParts

    PileOParts Silver Member

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    Happened to see a tire blow on an unloaded semi lowboy going northbound across a wide median when I was going southbound. Like an explosion -- loud as one, big cloud of dust and dirt, tread and carcass shreds flying out like shrapnel. Most impressive.
     
  19. Baldhead_J

    Baldhead_J Gold Member
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    Thanks for making a go at it. Guys like you and @dieselgman create "scenes" and push the economy.
     
  20. thumper

    thumper Gold Member
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    I don’t know since I wasn’t there.
     
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