I have a Heartland Sundance that came with Towmax. I made 4 campouts, about 200 miles, and noticed a tire seperating. The Heartland forum has 100's of Towmax tire complaints of blowouts and tread seperation. They are junk !
I bought 4 new Maxxis and have not had any problems since. I did a lot of research and Maxxis has the best reputation for ST tires on the market.
I found that Carlisle and Goodyear Marathons also have terrible reviews. The Goodyear G614 tires have good reviews but cost a small fortune.
I dont know anything about the Geo Star, but I would do my homework before purchasing. You dont want to end up in the same boat your already in.