It may depend on how long the trailer is in storage and at what pressure the tires
the tires are stored. Higher pressure may result in more loss over a period of time.
FWIW my toyhauler sat from November of last year to September of this year and the Sailun LT tires went from 100 psi to about 95 psi. Which is pretty comparable to what the change is in shorter periods. IMO 10-12 psi seems to be a bit too much. Probably not enough to be concerned with though.
If you're running ST tires the problem could be related to the thinner sidewalls of an ST tire. :)
