What PSI for tires?

Generally speaking, if you're on the tires that came with the rig- fill them to whatever the tire placard on the side says.

If you've upgraded tires, go by tire inflation load tables (maybe with a 10-15% increase to account for differences in side to side weights).

As for putting air into nitrogen tires, air is already 78% nitrogen (according to Google). Just top them up and you're fine.

There is a recent thread on TTs about nitrogen filled tires.

We don't know what tires you have on your FW, or the GVWR of your FW. In most cases, if ST tires are original, or replacements same as original, you would air them to max sidewall pressure. Reason being, the manufacturers usually install the least, but just capable tire for the trailer. In this case, that tire is only capable, using max pressure.

Jerry

Over the last 3 decades we have normally filled our ST tires on our towables (TTs, 5er, toy hauler) to max psi as stated on sidewall, although we usually had them about 5psi below max to reduce bounce when towing. With our LT tires and our class A tires we can choose to use actual weights, that being said we still air them up regardless of weight about 5-10psi below max, that way our tires have plenty of load carrying capacity while reducing the harsh ride that max filled tires can present. Never had a blowout or catastrophic tire failure while RVing, and yes we have been over the 65mph threshold here and there pretty much every trip. If your 5er has ST tires best to fill to or near max psi for best performance, LT tires can be filled to only handle actual weight of rig, again we fill close to max psi for added weight carrying capacity.

What tires....size/load rating?

What weight is being carried by the axles?

My 5vr has 16" 'G' Rated...Max Side wall is 110#
I run them at 100#
Even wear across the thread

I check/adjust in AM on travel day and then repeat on NEXT travel DAY


N2 in tires......
If it was FREE OK
Air has 78% vol N2 and 21% vol O2 ..... so air up with standard air compressor
(You'll be filling with 78% N2)


N2 is GREAT if you have an airplane or Race car
RVs....gimmick

I run my LR D TT tires at 65 psi for maximum weight carrying ability and, since I believe flex builds heat, minimum flex. And I too check the pressure and air up before every travel day.

Our fiver was equipped with G rated tires with a max psi of 110. I have found that running at 105 lbs gives smooth towing and the wear is perfect across the tires. As far as weighing I don't go there.

Your new to you 5th wheel tires on a trailer operate in a completely different environment. Trailer tires are close spaced toward the center of the vehicle unlike a motorhome/truck/van/suv/car/etc where the tires at the front corners turn around corners and the rear tires simply follows the fronts. So sure...they don't need max sidewall pressures.

The tires on our trailers twist/side scrub around corners or tight backing maneuvers. Much more stress on the tires carcass/treads so max sidewall psi helps in holding the tires shape and eliminating internal stress.

Now if someone has overtired a trailer like 16" load G tires with 4080-4408 lbs capacity on 5200-6000 lb axles then a lower pressure may be needed.

way2roll wrote:
As ambient temps drop I usually find I need to air up all the vehicles a bit.

Ambient temp is very important. When you are setting tire pressure you need to be aware of what temp you are at currently and what temp you will be driving at. Where i live there can be a 50 degree swing. Dont go setting tire pressure high on a cold night when you are gonna be driving in warming temps the next day.

Check the GVWR sticker for the recommended pressure. Probably sidewall max.

The nitrogen filled tires is a Hoax. There is VERY LITTLE difference in pressure rise with nitrogen of just plain air which is mostly nitrogen.

Best to weigh the RV at each wheel and air accordingly, but only when tires are cold.

Ken