Can you put air in nitrogen filled tires?

[gmacklem]

My trailer tires came nitrogen filled from the dealer. When it is 80+ degrees out , they read right at 50 psi. I checked them when it was 70 out in the morning and they read 47 psi. So I would like to get them to 50. Can I put air in them or should I find a place that does nitrogen?

Also, if they read 3 lbs low at 70 degrees, can I put 3 more lbs in them after they have heated up from running and are maybe reading 50 lbs or does it not work like that?

[KyDan]

Consumer reports magazine says air or nitrogen is fine. They found no appreciable
difference or advantage of nitrogen vs air.
Remember atmosphere is about 80% nitrogen anyway.
Fill your tires to the correct pressure at normal outside temperature. I try to fill mine
when the sun is not shining on them and we have not been traveling for at least a
few hours.
The numbers given on the tire sidewall or the door post of your car expect the
pressure to increase as the tire heats up.

[Dave_Monica]

You can top them up using air. The nitrogen filled tires have been a source of debate an whether it provides any real benefits vs the cost.

Always set the cold inflation pressure to the maximum regardless of the ambient temperature. Manufacturers allow that the pressure will increase as they heat up.

Dave

[rattleNsmoke]

One of the advantages of Nitrogen filled tires is the consistency of air pressure readings hot OR cold. In your case with a 3lb difference in a ten degree range my bet is someone already added plain ol' air to them. Do yourself a favor and just air them up as normal and call it a day. The Nitrogen hype is just that.

[gmacklem]

Wow, I have posted 2 questions in 2 days and got responses immediately. This is a great forum thanks to guys like you.

As for my problem, I will air them up and not worry about the nitrogen.

[F and E Damp]

Don't use the pressure molded into the sidewall as your normal pressure. That's the maximum allowable, not the working pressure.

To be accurate with regard to working pressure you should really weigh the Microlite to see how much weight the tires are carrying and then use the manufacturer's pressure/load chart to find the pressure you need.

[OldCoot]

Air to max cold pressure on the sidewall and you will be good to go. Trying to adjust air pressure to a load is a pita and you will be making a trip to the scales everytime you hook on the trailer. IMO, totally unnecessary.

[Oakman]

Originally Posted by OldCoot

Air to max cold pressure on the sidewall and you will be good to go. Trying to adjust air pressure to a load is a pita and you will be making a trip to the scales everytime you hook on the trailer. IMO, totally unnecessary.

X2!

[wmtire]

Originally Posted by gmacklem

My trailer tires came nitrogen filled from the dealer. When it is 80+ degrees out , they read right at 50 psi. I checked them when it was 70 out in the morning and they read 47 psi. So I would like to get them to 50. Can I put air in them or should I find a place that does nitrogen?

Also, if they read 3 lbs low at 70 degrees, can I put 3 more lbs in them after they have heated up from running and are maybe reading 50 lbs or does it not work like that?

Our unofficial rule of thumb, is that tire air pressure will rise or fall about 1 lb per 10 degrees of ambient temperature...............if taken at the same altitude.....but that's regular air and not nitrogen boosted/filtered air. To be perfectly honest, there is no way to know if you truly have nitrogen boosted/filtered air in your tires. It looks good on that sticker though. LOL

You should (if possible) adjust/measure air pressures at cold inflation as others have pointed out. This is before the tires have heated up.

A lot of tires not only have the maximum inflation pressure molded on the sidewall, but will also state it's cold pressure, after the number.

[bakken]

Originally Posted by OldCoot

Air to max cold pressure on the sidewall and you will be good to go. Trying to adjust air pressure to a load is a pita and you will be making a trip to the scales everytime you hook on the trailer. IMO, totally unnecessary.

I have no idea why you think it would be necessary to scale the camper before every trip. I seriously doubt that the gross weight of our fifth varies by more than a hundred pounds between trips.
And if one has good tires, there is no need to run them at maximum pressure either.
Even at full GVWR, the D-rated Maxxis tires I put on our unit only need to be aired up to 45 psi, although I do run them at about 55 psi just for a safety margin.
So not much more work airing my tires to 55 psi than 65 psi.

[F and E Damp]

I wasn't suggesting a weighing exercise before every trip, just once to get a feel for the weight the tires are carrying on a typical trip. If you inflate to the pressure molded into the sidewall, you'll get wear in the center of the tread, resulting in tire replacement before you would have had to do had you used a more realistic pressure.

FYI, my Class A tires have a sidewall pressure number of 120 psi, but based on the weight of my rig in normal use, a pressure around 95 psi is appropriate for our normal departure loading. I've only weighed the rig once, since our loading is fairly consistent from one trip to the next.

BTW, if you search on this subject, you'll find a post from me about why nitrogen is used in airplane tires. As I said in that post, you only need to pay for nitrogen if your rig can accelerate to 150 mph in 2 miles and then you can fold the wheels up into a sealed box.

[Herk7769]

Interesting article on Nitrogen:

http://www.nytimes.com/2008/03/09/au...MOTO.html?_r=0

[OldCoot]

Originally Posted by F and E Damp

I wasn't suggesting a weighing exercise before every trip, just once to get a feel for the weight the tires are carrying on a typical trip. If you inflate to the pressure molded into the sidewall, you'll get wear in the center of the tread, resulting in tire replacement before you would have had to do had you used a more realistic pressure.

FYI, my Class A tires have a sidewall pressure number of 120 psi, but based on the weight of my rig in normal use, a pressure around 95 psi is appropriate for our normal departure loading. I've only weighed the rig once, since our loading is fairly consistent from one trip to the next...

Trailer tires are usually age out long before they wear out. Have run max pressure for years in our LR D tires and never wore one in the center. Trailer tires are a completely different design from a class A or tv tire. They are not designed to give traction or steering. Built strictly for rolling and extra side loading caused by turning. Less air increases rolling resistance and thus generates heat.