I have a 2013 Heartland North Trail 22FBS Caliber Edition Travel Trailer, purchased new in 2013. I use it for two trips each year. I have replaced the same axle twice (rear, I think) and I am looking to upgrade to 5200# axle and 15" wheels. I do not believe my trailer has been overloaded, stowing not more than several hundred pounds of food, clothing, and gear. I think tight turns might be getting us? We have also worn out the rear tires, wear is on the inside and rather sudden. I am wondering whether heavier axles, larger tires, and better quality tires will be worth the $3500 investment. Obviously, this is no excuse to overload our trailer nor to make tight turns, but I am wondering if it can help? Also, we are getting mixed answers as to whether we should go with straight axles or those flexible (rounded?) axles? Any advice would be appreciated. Thank you.