I know there has already been some discussion on the subject but I am not sure the question I have was answered.  Getting ready to help trailer 2 horses about 5 hours in about 10 days and am concerned about tire pressures in those trailer tires.  There always seems to be a big difference between recommended pressure which sometimes is stickered (in a car it's in the door jamb) and the max tire pressure found on the tire sidewall.  For those of you that say pump the tire up to the max pressure, is this done before or after the load is on the trailer?  These 2 horses will probably add close to 2400 lbs to the trailer.  I need to verify that the tires are actually trailer rated and not passenger tires.  By the way, this is a gooseneck Silver Star 3 horse slant load trailer.

Thanks.

If your trailer has 16" wheels, you probably have  D or E range tires installed. These tires are typically inflated to 80- 85psi. ( check the sidewall for the proper inflation) Trailers don't usually have stickers that indicate an inflation schedule. On several tire manufacturers' websites, you will find that they recommend a max inflation usage.

A passenger tire will start with  P235/75/15 etc. The letter P indicates a passenger tire. Most of these will be in the 15" range.

If a tire is inflated to a given pressure, that pressure will not change with an additional load applied. All tire pressures are inflated to a cold setting. Once the tire is used, this pressure will rise due to heat and air expansion. When the tire is hot, the additional pressure should not be bled off. This additional pressure is a working pressure factored by the manufacturer. 

Hope this helps.

BOL  gard

Thank you, Gard.  This is excellent information and what I was looking for.  I will feel more comfortable making this upcoming trip.  The biggest thing you cleared up for me is that the increased load (adding the horses) to the trailer does not increase the psi in the tire.  They are definitely trailer rated tires as my girlfriend mentioned the 80 psi max pressure on the sidewall.  She says the trailer is actually stickered near the gooseneck with the recommended pressures.  If anything, this whole discussion and my passing along info to her has made her and I more aware of the importance of keeping the tires iproperly inflated.  After all, it is precious cargo.

Thanks again for the post.

Wayne