My trailer has been sitting in the lot next door for several years. Both tires were very low on air. I want to tow my 17' Cape Horn to Tennessee for a few weeks but I'm worried about the tires. I put 48 psi in them yesterday and checked this morning. Both had lost 3 PSI over night. The tread is great on both tires but the sidewalls have cracks. I don't want to buy new tires because I rarely use the trailer. I know temperature changes can affect pressure, and I'm hoping that is the reason for the drop in pressure. Is there any way of knowing if the tires are healthy enough to take off on a 800 mile trip?