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TexasPilot71

Trailer tire pressure

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Silly question I know. I mean the pressures are listed right on the tire (see photo below). But I checked all six tires and they’re all consistently 31-33 psi yet the tire calls for 65 psi. I’ve had the trailer two years and they’ve never looked “low” with the boat on it and they are filled with nitrogen so I haven’t added any air. 

The consistency of the current pressures make me question the recommended tire pressures, but I guess I just need to take them all up to 65?  Any thoughts? 

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They didn’t look low probability because of the extra reinforcement in the sidewalls of the ST tires.

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Old rule of thumb is to run trailer tires at the sidewall pressure. Keeps them more stable, especially when doing tight turning and prevents sidewall rolling in and scuffing, which it looks like your tires have seen, from the pic. But if the load (weight of load) on the tires is light, center of tread will wear faster and ride will be harsh with full pressure in them..

They may not look low, but also can heat up at highway speeds, due to the lower than advertised pressure. BUT, some tires are more forgiving that others. Are the outside tread areas wearing faster than the center? Load on the tires (boat trailer weight) have a lot to do with the pressures too.

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8 hours ago, TexasPilot71 said:

Silly question I know. I mean the pressures are listed right on the tire (see photo below). But I checked all six tires and they’re all consistently 31-33 psi yet the tire calls for 65 psi. I’ve had the trailer two years and they’ve never looked “low” with the boat on it and they are filled with nitrogen so I haven’t added any air. 

The consistency of the current pressures make me question the recommended tire pressures, but I guess I just need to take them all up to 65?  Any thoughts? 

So you have them filled with pure nitrogen, or just regular air pressure which I think has 80% nitrogen?

If you have them filled with pure nitrogen, that's why they look ok and are maintaining the same look like they're filled.  Pure nitrogen maintains it's on pressure and isn't affected by outside temps or pressure changes even.  But they also probably look fine and not low because the boat isn't on it.  They're only carrying the trailer load.  Wait till you put the boat on it and they'll definitely look half flat at 31-33 psi.  Question is, what type nitrogen do you have in them?

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Came from the factory with pure nitrogen as most tire shops do now. I suspect the pressure was the same when we last had the boat on it but I didn’t check. 

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Over the years, when I empty the tires to lower the trailer to get the boat off of it [to clean] I'm amazed that even when most of the air is out, it still doesn't look flat. I use just regular air. The tires hold their pressure pretty well as I rarely have to put any in.

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32 minutes ago, SST said:

Over the years, when I empty the tires to lower the trailer to get the boat off of it [to clean] I'm amazed that even when most of the air is out, it still doesn't look flat. I use just regular air. The tires hold their pressure pretty well as I rarely have to put any in.

Good to know.  Thanks!  I need to air them up.  Planning a Florida trip on March 9 if I can get the motor fixed this weekend.

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16 hours ago, Hatem said:

So you have them filled with pure nitrogen, or just regular air pressure which I think has 80% nitrogen?

If you have them filled with pure nitrogen, that's why they look ok and are maintaining the same look like they're filled.  Pure nitrogen maintains it's on pressure and isn't affected by outside temps or pressure changes even.  But they also probably look fine and not low because the boat isn't on it.  They're only carrying the trailer load.  Wait till you put the boat on it and they'll definitely look half flat at 31-33 psi.  Question is, what type nitrogen do you have in them?

Nitrogen isn't required. Fill with what is simple and available which is air. Yes, pressures can change a few pound with temps, so check em once in a while. That is the only difference.

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8 hours ago, Dgiles said:

Nitrogen isn't required. Fill with what is simple and available which is air. Yes, pressures can change a few pound with temps, so check em once in a while. That is the only difference.

Thanks.  I was asking the OP (TexasPilot) if his tires he was asking about were filled with pure nitrogen or not and apparently they are.

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Yeah, I'll just use air.  I have a large compressor at home.  Guess I need a portable high pressure pump capable of bringing them to 65# without taking all day.  Or haul the trailer to air...just need to find some.

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On 2/26/2019 at 7:21 AM, Hatem said:

So you have them filled with pure nitrogen, or just regular air pressure which I think has 80% nitrogen?

If you have them filled with pure nitrogen, that's why they look ok and are maintaining the same look like they're filled.  Pure nitrogen maintains it's on pressure and isn't affected by outside temps or pressure changes even.  But they also probably look fine and not low because the boat isn't on it.  They're only carrying the trailer load.  Wait till you put the boat on it and they'll definitely look half flat at 31-33 psi.  Question is, what type nitrogen do you have in them?

Even pure nitrogen is affected by temperature. It’s a gas and the Ideal Gas Law still applies. It also does not maintain its own pressure like liquid propane. It can if you have liquid nitrogen, but that’s not in the tires. 

Check out this article which covers nitrogen in tires. There are benefits, but it’s nothing Earth shattering. 

Anyways, pump those trailer tires up before your road trip. 

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With a empty trailer going 300 miles. I do 25 instead of 32 psi. I to avoid the center only running on the road. I do check that trailer hitched up DOES have axles parallel to to vehicle axle. If not ? Find & repair before driving.

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14 hours ago, rjbergen said:

Check out this article which covers nitrogen in tires. There are benefits, but it’s nothing Earth shattering. 

Nothing earth shattering I agree, but it's much more stable in tires than oxygen alone just like that link says.  It doesn't permeate through the rubber like O2 because it's molecular structure is thicker.  If you ever watch NASCAR or Formula 1 etc., that's all they use for exactly that reason so they maintain tire pressure throughout the race.  So even temperature changes won't affect it much because it just doesn't escape like O2 does.  Heck, even in pit stops they're only changing 1/2 a psi up or down to make a huge difference and that's a perfect example of how stable it is.  Another reason why newly installed tires come with nitrogen in them and not O2.

14 hours ago, rjbergen said:

Anyways, pump those trailer tires up before your road trip. 

Oh I do.  Between all my vehicles, I have 26 tires to maintain.  I have to deal with 6 just on my daily driver so yeah, I maintain them on a regular basis.  :) 

Speaking of my daily, I had a horrifyingly gratifying experience yesterday.  My last DEF fluid level alert showed up on my dashboard about 3 months ago.  I went to fill it up and it back-flowed.  I figured I was screwed and somehow some water or  diesel or something got into the system and it crystalized and there was a major blockage and I'm dealing with a super costly repair.  So I kept driving and made an appointment with the dealer to have it looked at and by the time the appointment came up, I had passed the mileage left before the engine limits the speed to only 50 mph and I was dreading it as the miles expired while I was on the highway but it never turned.  I was shocked and thought maybe the sensor wasn't working and my speed was fine without any DEF fluid in the tank, or maybe the warning is just a scare tactic by Ford and it really doesn't do it LOL.  Wishful thinking, I suppose.  So I said the heck with it and blew off the appointment at the dealer and kept driving until a few days ago (3 months later) when the alert for low DEF fluid shows up on the dash again and I had 100 miles left to fill it up before I'm limited to 50 mph again.  I'm thinking it's just an automatic cycle that the computer goes through even though it's already empty and it never limited the speed the last time and didn't think much more of it.  Ran out of the 100 miles and sure enough, engine draws down and stays right at 50mph and I'm @#$%@#ting my pants lmao!  I couldn't believe it actually worked because it didn't the last time.  Now I now I can't fill it because I know it's blocked from the last time and so I'm scratching my head not knowing WTF to do.  I stop at a gas station on the highway to see if there is a slight chance in heII that somehow it does take the fluid and maybe the blockage went away by some miracle.  I buy a container of DEF ($30 and it takes 2) and start pouring and sure enough, it goes through!  I was like WTF!?  Apparently the last time it must've given me a false reading that it was almost empty when it wasn't.  Which also explains why I kept getting backflow when I tried filling it and the engine also never limited the speed when the miles ran out?!  Very strange but I was psyched!  If that system was crystalized and all clogged up, that would've been a $6K+ repair job!  Thank you, God!

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4 hours ago, Hatem said:

Nothing earth shattering I agree, but it's much more stable in tires than oxygen alone just like that link says.  It doesn't permeate through the rubber like O2 because it's molecular structure is thicker.  If you ever watch NASCAR or Formula 1 etc., that's all they use for exactly that reason so they maintain tire pressure throughout the race.  So even temperature changes won't affect it much because it just doesn't escape like O2 does.  Heck, even in pit stops they're only changing 1/2 a psi up or down to make a huge difference and that's a perfect example of how stable it is.  Another reason why newly installed tires come with nitrogen in them and not O2.

Oh I do.  Between all my vehicles, I have 26 tires to maintain.  I have to deal with 6 just on my daily driver so yeah, I maintain them on a regular basis.  :) 

Speaking of my daily, I had a horrifyingly gratifying experience yesterday.  My last DEF fluid level alert showed up on my dashboard about 3 months ago.  I went to fill it up and it back-flowed.  I figured I was screwed and somehow some water or  diesel or something got into the system and it crystalized and there was a major blockage and I'm dealing with a super costly repair.  So I kept driving and made an appointment with the dealer to have it looked at and by the time the appointment came up, I had passed the mileage left before the engine limits the speed to only 50 mph and I was dreading it as the miles expired while I was on the highway but it never turned.  I was shocked and thought maybe the sensor wasn't working and my speed was fine without any DEF fluid in the tank, or maybe the warning is just a scare tactic by Ford and it really doesn't do it LOL.  Wishful thinking, I suppose.  So I said the heck with it and blew off the appointment at the dealer and kept driving until a few days ago (3 months later) when the alert for low DEF fluid shows up on the dash again and I had 100 miles left to fill it up before I'm limited to 50 mph again.  I'm thinking it's just an automatic cycle that the computer goes through even though it's already empty and it never limited the speed the last time and didn't think much more of it.  Ran out of the 100 miles and sure enough, engine draws down and stays right at 50mph and I'm @#$%@#ting my pants lmao!  I couldn't believe it actually worked because it didn't the last time.  Now I now I can't fill it because I know it's blocked from the last time and so I'm scratching my head not knowing WTF to do.  I stop at a gas station on the highway to see if there is a slight chance in heII that somehow it does take the fluid and maybe the blockage went away by some miracle.  I buy a container of DEF ($30 and it takes 2) and start pouring and sure enough, it goes through!  I was like WTF!?  Apparently the last time it must've given me a false reading that it was almost empty when it wasn't.  Which also explains why I kept getting backflow when I tried filling it and the engine also never limited the speed when the miles ran out?!  Very strange but I was psyched!  If that system was crystalized and all clogged up, that would've been a $6K+ repair job!  Thank you, God!

Fix Or Repair Daily!  My dad has had Fords all my life (beginning with a 1974 F100) and every one of them have been a nightmare.  He had "the bad" diesel that would just quit and leave him stranded on the side of the road.  His current F350 (2016 I believe) seems to be holding up okay.  My Ram 2500 has 61k now (I know that's not much) but it's running great.

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My F250 diesel has 180000 miles on it and other than an alternator and radiator it's been pretty much trouble free... I am religious about maintenance tho.

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I remember those older first ford electronic pickups.  Died every trip in the summer.  coast to shoulder of road . Lift hood.  40 minutes later. Close hood drive again.  Repeat

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Trailer tire stickers are WRONG !!.......... You go by the tire companies ratings for the size you are using.

Steel belted metric auto tires versus LT truck tires.  Are not even close to each others pressures at maximum.

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The wheel wells of aircraft are not pressurized. This is why a plane flying at 40k [or any other altitude] has nitrogen in their tires.

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1 hour ago, SST said:

The wheel wells of aircraft are not pressurized. This is why a plane flying at 40k [or any other altitude] has nitrogen in their tires.

That's a great observation, SST.  Even though the nitrogen in the tires is pressurized, the wells themselves don't need to be since the nitrogen isn't affected by the drastic changes in altitude pressure or even temperature. 

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the sticker on trailer is not wrong they specify tire size and weight vs tire pressure similar to the sticker on the door of a vehicle . Its not advisable to use passenger tires on a trailer. ST tires are designed for the unique conditions of trailer use .The maximum pressure on a tire sidewall is exactly that, not necessarily the appropriate pressure for your specific trailer 

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Passenger tires are SUPPLIED AS standard equipment by companies.  They outlast ST & lT buy 40,000miles. Easily

DOT     allows passenger tires on trailers IF  IF  they are derated by 20% of maximum capacity rating.   NO trailer tires CAN EVER be used on a passenger car.  They BLOW OUT frequently due to unsafe construction standards allowed.by the law & tire makers.   A person is worthless on trailer tires.  To be protected on car tires.    All for a bigger profit.

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