single axle trailer tires

[AirTool]

My take on nitrogen in tires:
Unless the pull a vacuum on your mounted tire (which would be pretty hard to do while maintaining a seal) and evacuate all of the non-nitrogen gases, then it is a waste of time and money....

Not true...as long as there is no free water in there. The amount of moles or mass of air at atmospheric pressure prior to filling up to 30 plus psi is nil. Sucking a vacuum or purging would be better but it would really go unnoticed. ...just don't want any free (liquid) water in there.

[AirTool]

The other benefit of nitrogen is it doesnt change pressure much. The pressure in my tires has stayed at 80 all year without having to add any air.

You will read the nitrogen doesn't leak out as fast....not sure why because the nitrogen is a smaller molecule then oxygen and the are both diatomic (exist is paired molecules with pure; N2 O2, etc.)

Maybe the leakage is less because the operating temperature is lower as discussed above. Higher temp -> higher pressure -> faster leakage

[jmo]

ok, quick question: for those running 50 psi+ on tires, did they come from the dealer like that? Mine were at I think 25 and I've bumped them up to 35. Need to double check what the tires are rated (tandem axle).

Also, my truck tires are rated to 50, but Ford recommends 35. I wonder if trailers are the same. And one last question: does the increase in pressure improve the ride or make it bounce more? I'd think it bounces more.

I just replaced my trailer tires - US made Marathons and the tire place pumped them right up to 65 psi as they should be. The key is that the air inside the tire is what actually carries the weight of the trailer & boat, so the amount your tire can handle is directly proportional to the pressure, max air pressure = max load capacity.

A 65 max psi trailer tire at 25 - 35 psi is a recipe for disaster , imho.

As for the truck tires, most trucks come with passenger tires, and hence the 35 psi recommendation. My tundra was that way, but with my custom 20" wheels, my sport tires have a max load of 51psi, and to achieve the same weight bearing ability of my Passenger tires at 35 psi, my sport tires need to be at 45 psi. For around town driving I keep them at 40 psi, but when I tow I jack the fronts to 45 and the rears to 50.

Yes, the higher tire pressure will compromise the ride comfort a bit, hence why I run at 40 with no load or trailer. High pressure yields better fuel economy though.

Hope this helps,

jmo

[AirTool]

Putting 65 psi in a tire that needs only 50 for the load will cause the tire to wear improperly. Not a biggy if you don't put a lot of miles on the tire. But still fact nevertheless.

So, again, weigh your trailer; get the axle load; divide by the number of tires, and look up the proper pressure for that load on your tire.

Then keep them inflated at that pressure. Be sure to check the pressure BEFORE you tow or even park it in the sun. Black tires have an emissivity close to 1 and get hot in the sun. I checked my tires in a parking lot one time and the sunny side pressure was about 15 psi higher than the shady side. Needless to say, I didn't deflate the hot one down to the "cold" pressure.