Thank you all so much. I think I will take to a good local tire & alignment (have one available) that does RV's. have them check the axles and make sure their not bent. Check the alignment and all things on the axles/hubs , etc. I may stay with 15" and get another set of tires. Maybe the Maxxis 8008. I am retiring in a couple months and will be using it more often. Also, I think I will keep covering and take weight off the tires and look for a conditioner. I will keep reading responses for ideas. Thanks again to all. I love this site.