tire pressure for t@b 400 tires

@kaylevine1--the tire pressure is stamped on the side of the tire.  You should go by that stamp.  Unless your unit is new and you have been the only owner, you do not know if those are the original tires and then the sticker may or may not be correct.

Have to disagree with the comments here to use the sidewall.   The tire sticker shown below can be found on the drivers side of your trailer.  The specific tire size, specs and cold tire pressure number all went into determining the cargo weight number shown.  In this example, using a 235/75/15 tire at 50 PSI gives me a maximum of 1010 lbs.  If I load at 45, I can expect a drop in the cargo carrying capacity but will get a softer ride with less bounce especially when the trailer is empty.

The tire sidewall, however, is a maximum tire pressure not the "recommended" one and you would vary that figure depending on your load and specific use.  As I'm not an expert, perhaps this post from TireTrack might be of help from an "expert".   Of note is this paragraph although the entire post is of value:
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=8

• "The pounds per square inch (psi) pressure number branded on the tire's sidewall identifies the maximum cold inflation pressure that specific tire is rated to hold. However, the tire's maximum pressure is not necessarily the correct pressure for every vehicle upon which the tire can be used (almost all vehicle manufacturers' recommended tire inflation pressures are less than the tires' maximum pressure)."

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On both my T@B and my Airstream, we run ST tires but especially on the Airstream, I don't follow the sidewall because it would be crazy high.  On the Boondock Light trailers, we have the Rainier per the attached PDF.  If the tire MAX and the sticker match then great but given the variety of tires that might get used over time that fall under a ST rating of the Size Dimensions specified by the manufacturer, you will likely have better results over a range of wheeled equipment if you used the door sticker inflation figures instead of the tire.  YMMV

@DenisP and that is the same advice I have been given by tire stores too, always run ST tires at the maximum cold inflation pressure on the sidewall.

@kaylevine1
These guys nailed it in their explanation of COLD TIRE PRESSURE
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73


This is from the Unofficial Guide definitions section:

·         Cold Tire Pressure:  This appears on the tire sidewall where it states the Maximum PSI.   Most of us understand this to mean at first light when the car hasn’t been driven anywhere as driving heats up the tires and the air inside.  Engineers would more specifically say that the MAX is the inside tire pressure when the ambient temperature is at the index value of 68-deg F and that this changes by 2% for every 10-degree of temperature change.   For the rest of us this means that since the vehicle rests on the tires, and tires are supported by the air inside, when it’s hot out the air expands and when its cool, the air contracts.  If you drive a perfectly inflated vehicle from Florida at 70-degrees average temperature to Canada with a 45-degree average temperature, the tire will need more air when measured cold the following morning because cooler temperatures are contracting the air volume and the air volume is what keeps the tire inflated.  The reverse is true when you go in the opposite direction and you’d need to let some air out when you got to Florida to stay at your MAX rating.   This is why you check tire pressure seasonally.

After buying my T@B a three weeks ago, I'm still going through everything.  Today I checked my tires and they were at 40 psi, I'm assuming that's what the previous owner had filled them at.  I filled to the recommended 50 psi on my tires and hauled it 100 miles today to the opposite side of town and found the trailer very bouncy...much more so than at 40 psi, which makes sense.  The trailer was empty, so I'm wondering if I should lower the psi when empty or keep at max...I figure the tires will last longer when properly inflated, but it felt like I was driving on two balloons.  What do most of you do?

40 lbs works very well on my T@B 400, through about 15,000 miles or so. 

I recently bought a Ryobi cordless tire inflator and it is a great tool. Anyone else use one of these?

look https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf