Tow Vehicle Tire Pressure

Discussion in 'Tow Vehicles, Hitch & Towing' started by mpotapa, Oct 31, 2017.

  1. mpotapa

    mpotapa Member

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    I am currently having an issue with my 2016 Dodge Ram. All spring and summer my tire pressure was fine. Just recently since it got colder my tire pressure monitoring system says my tire pressure is between 30-32 on all my tires and tells me to fill them up to 39 PSI. The issue is when I hook my compressor up to the tires it shows 39 PSI. When I use a tire pressure gauge it says 39 PSI. I am going to call my dealer tomorrow but was wondering if anyone else has had similar issues. I pick up my 2018 Rockwood Roo 233s this Saturday and want to make sure I drive the 100 plus miles with the proper tire pressure.
     
  2. JustRelax

    JustRelax Active Member

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    Trust the gauge not the auto system. You'll be fine to pick up the camper if you can't get the system worked out. Congratulations on the new unit!
     
  3. BikeNFish

    BikeNFish Well-Known Member

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    Last edited: Oct 31, 2017
  4. Fbird

    Fbird Active Member

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    Get a good digital gauge and check the pressure. I've found a lot of cheap gauges and those on compressors aren't reliable.
     
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  5. f5moab

    f5moab Retired from the Federal Government

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    Drop in temp by 10 degrees will lower TP by 1 psi. As for gauges, yes there are tons of cheap ones out there; the least accurate I believe is the compressor gauge. however, I go by what the TP sensor in the tire says. From many articles those are quite accurate.
     
  6. silvermickey2002

    silvermickey2002 Morris County, NJ

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    The TPS in my Camry does the same thing in really cold weather. I purchased a good digital pressure gauge a number of years ago from Sears. I trust it over the TPS in the Camry. It also goes with us on trips.
     
  7. mpotapa

    mpotapa Member

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    My concern is if you TPS isn’t accurate I don’t want to keep putting air in the tire until it blows.
     
  8. BikeNFish

    BikeNFish Well-Known Member

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    My tires are rated up to 80 psi. so it shouldn't be an issue if a few extra pounds are put in.
     
  9. J Starsky

    J Starsky Well-Known Member

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    A man with one watch knows what time it is.....
    TPS, Stick Gauge, Dial Gauge, 50lbs vs. 120lbs gauge, etc will have tell you a different time. You will never synchronize those watches [%]
     
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  10. Halford

    Halford Well-Known Member

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    I just bought Bridgestone tires from Costco which filled the tires with Nitrogen. Cold or heat weather has no effect to Nitrogen as Costco claim. I am checking this out to see if this is true. First time I have Nitrogen in tires. When I had tires with air in em, I see difference in pressure in tires when the weather change. Most of time I pay more attention in adding air to tires in colder weather than in summer.
     
  11. J Starsky

    J Starsky Well-Known Member

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    I tried Nitrogen in a standard reference test tire SRTT (google it) and still required adding air to maintain test pressure. A man with one watch knows what time it is..... Unless in Greenwich I suppose.
     
  12. tombiasi

    tombiasi Well-Known Member

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    My tires have 78% nitrogen already.
     
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  13. f5moab

    f5moab Retired from the Federal Government

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    That could happen if you are using one of those so-called accurate electronic hand gauges or an old fashioned mechanical gauge. However, due to the federal laws, the in-tire, factory supplied sensors are quite accurate and as accurate as any of the gauges you would get through Amazon. Will it be exactly 32 psi? Will the gauge in your hand be at an exact pressure?

    In comparison, my past four vehicles were within one psi of a very expensive and very long stick pressure gauge. And I use this gauge for my trailer tires and there it shows the TP sensor I use on my trailer tires to be within two psi. I will say the stick pressure gauge was better at smacking a rattlesnake on the head which I probably could not have done with one of the tire sensors. :D

    And I would hope most would get a sense of coming close to blowing the tire while adding air. If not, duck really quick when it goes BOOM.

    As for nitrogen, I put nitrogen in my tires all the time; about 78% if I remember right. And nitrogen is affected by temps, but at only half the rate as standard breathable air. You will lose or gain about a half pound with every 10 degrees in temp change vs a full pound with air. Nitrogen is nice for tires on a stored vehicle since it does not retain moisture. It is also nice on airplane and racing car tires due to not supporting combustion.

    There is no problem using nitrogen, but not worth the extra price and the biggest problem with nitrogen is when you do need to add pressure to the tires, will you go back to the dealer to have it added, or use the air pump in your garage or at the nearest service station; at which time you will destroy what small advantage nitrogen will give you.

    I'll continue to use my compressor in the garage to add air when the temps drop and to help regulate when reducing air in the warmer months. I will also continue to use my sensors in the tires as I have since my 2003 Corvette. However, not all vehicles allow you to use the in-tire sensor. My Hummer had a system that did not show the inflation of each tire, but would warn you if one tire was underinflated and you had to determine which tire (yes, dump system). But my Vette as well as my pickups have all shown tire pressure for each separate tire.

    So we can all agree to disagree and hopefully, my tires won't blow up in my face.:eek:
     
  14. mpotapa

    mpotapa Member

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    So I got an oil change today and they filled my tires up. My gauges must not be very accurate because. I’ll be going off the tire pressure sensors my truck already has.
     
  15. MNTCamper

    MNTCamper Active Member

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    Folks ALL gases follow the ideal gas law (at the conditions we are talking about) PV=nRT, so P1/P2=T1/T2 with the temperature being in Kelvin. It does change with temp, but room temp being about 298K give you an idea of the magnitude change. A 5 degree C change from that (9F) results in about 5/300, or 1/60 change. regular air, nitrogen...all the same. Only thing that would change is if the tire filling had a high moisture (H2O) content initially and that actually condensed out when cold, then the pressure drop could be much more severe.
     
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  16. Halford

    Halford Well-Known Member

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    i checked my tires that has Nitrogen, no additional is needed since I bought the tires at Costco 2 months ago.
     
  17. 1380ken

    1380ken Well-Known Member

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    Temperature has no effect on air pressure at all. Ask Tom Brady.
     
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  18. f5moab

    f5moab Retired from the Federal Government

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    Has the temps dropped enough for a temp gauge to even register? With nitrogen it is approx one-half pound per every ten degrees. A slight drop in temps might not register on a regular TP gauge.
    My tires with good old air inside during the summer do not show a drop while the temps are similar. It is now, when the temps are dropping by about 50 degrees from when I last checked that shows a drop. And if I forget to add air, eventually the TP warning will come on telling me the tires are below the desired minimum pressure.
     
  19. 1380ken

    1380ken Well-Known Member

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    Almost all the power in your engine is from Nitrogen expanding. That is why compression ratios matter.
     

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