Air pressure in tires

[Hutch606]

G19FD with Endurance 215/75r14 tires (one size up from stock). Trailer claims 50 PSI, tire max is 65.

These tires are brand new, I bought trailer used with probably 1-2k miles (low!) and factory BOOM brand tires.

The old tires had 50 psi and appeared to be well maintained, guy followed all the rules. However they showed bad usage from under inflation, very visible.

So, does everybody use about 50 or does everybody else know you should claim 60 or ??

Thanks, want to confirm before filling with nitrogen.

[Mike134]

Skip the pure nitrogen, use plain old air which comes with 78% nitrogen.


I also upgraded from 205/14 to Endurance 215/14 and run them at 62 PSI to get the increased load carrying capacity that the upgrade offers. I'll keep an eye on the tread wear pattern, and might lower pressures a bit in the fall's cooler weather.

[eye95]

Base your tire pressures on the actual load. There are industry tables that tell you what PSI to use for the weight on the tire.

I am a fan of nitrogen. I use a TPMS and have to fill the tires once a year, when the TT comes out of winter storage.

[bikendan]

Originally Posted by Hutch606

Thanks, want to confirm before filling with nitrogen.

Please don't fall for the Nitrogen scam!

[tmkwasinski]

Sorry for this and redirecting thread. I too have bought tires for TT and truck and had the dealer give me the "nitrogen" pitch and fill. Then when having to add pressure be told "just add air". Then they claim they don't have the ability to put nitrogen in.
My brother bought a new car was being charged for "nitrogen upgrade". He told them to take it out....the price was deducted with nothing else being done.
Again, sorry

[RVPP]

Pretty straight forward:

https://www.goodyearrvtires.com/tire...n-loading.aspx

[Tundra 2014]

I made the same upgrade and run them @ 62 PSI w/ a 8000 lb trailer. You have to consider your max axle rating also. Goodyear has a chart that tells you tire load at PSI. No need to go any higher PSI for my set-up.

[DouglasReid]

Originally Posted by Hutch606

G19FD with Endurance 215/75r14 tires (one size up from stock). Trailer claims 50 PSI, tire max is 65.

These tires are brand new, I bought trailer used with probably 1-2k miles (low!) and factory BOOM brand tires.

The old tires had 50 psi and appeared to be well maintained, guy followed all the rules. However they showed bad usage from under inflation, very visible.

So, does everybody use about 50 or does everybody else know you should claim 60 or ??

Thanks, want to confirm before filling with nitrogen.

Run them at the max pressure the tires are rated for. It is hard on tires to be under inflated. They will last LONGER at full pressure than at lesser pressures.

Axle rating NOT important to the tires. Having more capacity than needed not a bad thing.

Nitrogen a waste of money.

[Jcyesiam]

Added guestion, tt tires cold psi 80 8000 trailet what pressure?

[RockyMtnMarty]

Learn a ton about RV tires at this web blog:

https://www.rvtiresafety.net/

Roger Marble is a 40+ year tire engineer and a true expert.

[The Evil Twin]

I wouldnt pay someone to put it in, but I put nitrogen in all my tires. Well, except the motorcycle tires. Its like $19 for a 120cf tank. More than enough for a couple years. I use it to seat tires so I use a little more than most folks would.

Originally Posted by eye95

Base your tire pressures on the actual load. There are industry tables that tell you what PSI to use for the weight on the tire.

I am a fan of nitrogen. I use a TPMS and have to fill the tires once a year, when the TT comes out of winter storage.

You use nitrogen and have to put more in every year?

[eye95]

Originally Posted by The Evil Twin

...You use nitrogen and have to put more in every year?

Um...yes, after the camper has sat all winter, as opposed to air, which has always required adding air every few months. I haven’t had to add nitrogen ever during the season.

Nitrogen is free from our local Costco. Last year, I had to add about 2 psi to each tire. To me, that reliability of pressure makes the use of nitrogen worth it. Air does not give you that reliability.

[TriGlide]

I check my tires on all vehicles every month and always have... Not gonna fall for the nitrogen bit... plain ole Air has worked fine for me my dad and my grandfather and great grandfather for 75 plus years so gonna keep using the free stuff.. If it ain't broke don't fix it...

[Larry-NC]

Originally Posted by eye95

Um...yes, after the camper has sat all winter, as opposed to air, which has always required adding air every few months. I haven’t had to add nitrogen ever during the season.

Nitrogen is free from our local Costco. Last year, I had to add about 2 psi to each tire. To me, that reliability of pressure makes the use of nitrogen worth it. Air does not give you that reliability.

Huh?
Air is 78% Nitrogen, 21% Oxygen.
Nitrogen occurs in N2 molecules, atomic weight 14 (per molecule)
Oxygen occurs in O2 molecules, atomic weight 16 (per molecule)

It is generally conceded that the smaller the molecule, the faster it will diffuse through a container. Consider Helium balloons. Helium has an atomic weight of 4 and diffuses through the skin of a balloon overnight, even though filled to only a few psi.

The oxygen molecules in air are BIGGER than nitrogen and should diffuse (leak) through the tire MORE SLOWLY than nitrogen molecules.

And over 3/4 of the molecules in air are nitrogen anyway.

Sorry, the assertion that air-filled tires leak down more quickly than those filled with pure nitrogen just isn't credible.

[SailorSam20500]

Originally Posted by RockyMtnMarty

Learn a ton about RV tires at this web blog:

https://www.rvtiresafety.net/

Roger Marble is a 40+ year tire engineer and a true expert.

I'll second this. If you dig far enough in Roger's posts, you will find that for TOWABLES he recommends running at the max cold inflation pressure.


I like this guy's discussion about putting nitrogen in tires. Beware, his language is a bit "colorful" and humorous...
https://autoexpert.com.au/posts/top-...elp-your-tyres

[The Evil Twin]

Originally Posted by eye95

Um...yes, after the camper has sat all winter, as opposed to air, which has always required adding air every few months. I haven’t had to add nitrogen ever during the season.

Nitrogen is free from our local Costco. Last year, I had to add about 2 psi to each tire. To me, that reliability of pressure makes the use of nitrogen worth it. Air does not give you that reliability.

Oh, 2 psi. Lol. Thats nothing. I was rather surprised when you said you added. I don't think I've added any in over a year. They are always 105-115 and I just call it good due to temperature fluctuations. The only reason I add any to the cars is because I let some out for the summer as pressure and temperature increase.

[eye95]

Originally Posted by Larry-NC

Huh?
Air is 78% Nitrogen, 21% Oxygen.
Nitrogen occurs in N2 molecules, atomic weight 14 (per molecule)
Oxygen occurs in O2 molecules, atomic weight 16 (per molecule)

It is generally conceded that the smaller the molecule, the faster it will diffuse through a container. Consider Helium balloons. Helium has an atomic weight of 4 and diffuses through the skin of a balloon overnight, even though filled to only a few psi.

The oxygen molecules in air are BIGGER than nitrogen and should diffuse (leak) through the tire MORE SLOWLY than nitrogen molecules.

And over 3/4 of the molecules in air are nitrogen anyway.

Sorry, the assertion that air-filled tires leak down more quickly than those filled with pure nitrogen just isn't credible.

Just relating my decades of personal experience using nitrogen.

Accept it or not.

I know others will listen with an open mind, and make the decision that they think is best, not necessarily mocking the decisions of others.

Oh, and on your science: Nitrogen molecules are slightly larger (physical size, not weight) than Oxygen molecules, way larger than helium “molecules”, vastly smaller than (undesirable) water molecules...

[eye95]

Originally Posted by The Evil Twin

Oh, 2 psi. Lol. Thats nothing. I was rather surprised when you said you added. I don't think I've added any in over a year. They are always 105-115 and I just call it good due to temperature fluctuations. The only reason I add any to the cars is because I let some out for the summer as pressure and temperature increase.

Just got the r-pod out two days ago. Tires look good, though I haven’t hit them with the gauge. I’ll let you know what this year’s result is when I get to that part of yearly set-up.

[The Evil Twin]

Originally Posted by eye95

Just got the r-pod out two days ago. Tires look good, though I haven’t hit them with the gauge. I’ll let you know what this year’s result is when I get to that part of yearly set-up.

I'm interested to do a test with mine now. Although it'll be a long one. Check temp and pressure, then check pressure at same temp a year from now. I honestly cannot see it being different. There has been consistent 10% variation every time I look. A little lower in the morning. A little higher in the afternoon sunny side. Actually started questioning my gauge. Now I just look at the TPMS value most of the time.

[eye95]

Once I “air” them up in the Spring (Summer, this year), I just monitor them with the TPMS. The pressure differences when the tires heat up are surprisingly low. After I finish my first trip this year, I will share the changes from morning cold to driving hot.

Driving hot is so much more of a change than caused by atmospheric temperature and pressure, that my only concern with those two is to check pressures in the morning cold to determine if I need to “air” up.