Re: [A/S] Tire Pressure ?

[Jim Dunmyer <jdunmyer@xxxxxxxxxxx>]

Dan,
  I have the common ST225/R15 tires (LR 'D') on our 25' Avion and also 
on our 'new' 30' Avion. The pressure has been set at 45-48 PSI on the 
old one and is presently at about the same on the new trailer.

You'll note a "max pressure" rating on the sidewall, along with a "max 
load" number. *IF* you are carrying the max load (2640#/tire), you need 
the maximum listed pressure. However, if your actual load is less, a 
lower pressure is called for. All manufacturers publish load/inflation 
charts for their tires, and everyone should consult them.

As a point of information, my 'new' trailer weighs not much over 
1500#/tire. Even when we get it loaded for travel, it'll not be much 
over 1700#/tire, well below the rating.

It's difficult to tell if your pressure setting is too high. Over a long 
period of miles, you'll notice the center of the tread wearing a bit 
more than the edges. You *might* notice that you're shaking your trailer 
to pieces, but that takes a long time also.

If your pressure is very much too low, you'll notice the tires getting 
hot, even on a cool day. Eventually, you might notice more wear on the 
outside of the treads than in the center. If the pressure is dangerously 
low, the tires will get VERY hot, VERY quickly. I've experienced a 
blowout on a truck with a very soft tire; it took just over a mile.

FWIW: As a gadget freak, I bought one of those infrared temperature guns 
for about $99.00 at NAPA. Mine has the laser pointer so you can tell 
exactly what it's looking at. Nearly every time we stop, usually at 
60-90 minute intervals, I grab that thing and check all 8 tires AND the 
wheel bearings. (no hub caps for me!) I've found that my truck tires 
will rise 30 degrees or a bit more above ambient, and pressure or load 
seems to make little difference. I think that's due to the kind of 
agressive tread. The trailer tires will rise about 20 degrees above 
ambient at most, and that's only on hot days and on the sunny side of 
the trailer. They normally feel "cool" to the touch, as do the wheel hubs.

Running the tires at the proper pressure will give you more traction and 
a better ride. If you want to experiment a bit, pump your car tires up 
to 50+ PSI and go for a ride; compare the feel to that with normal 
pressure, usually about 32 PSI.

                             <<Jim>>