Do you know how old your tires are? Just because they look all right and have plenty of tread doesn't mean they're safe. RV tires are especially vulnerable to damage due to age and the weight they bear.
Check out this website: http://www.dickmantires.com/rv_tire_age.html
Then check your tires.
Next time you're in a auto supply store, pick up a tire gauge for your tires. Mine hold 65 pounds and the tire gauge I had was for my toad. I couldn't get a true reading.
Make this a priority before your next road trip.