The duratrax havoks are a great tire for the sledge. Belted and lighter then the trenchers. I have not had a problem with rims cracking except for the 1/5 scale. Other then that they have been great!
I do agree they balloon a bit. But compared to others that can't even get to the same speed as the Sledge. I was impressed with the stock results. I would really have to think about the weight of going belted vs the ballooning of not.... but that's just personal conflict I have to talk with my...