Dell, the tires on mine are Goodyear G178 in the size 385/65R22.5. They are considered a supersingle by Goodyear and stand 43" tall and weight 183 without the wheel.
John, unless it is completely empty, and even then, a Deuce would probably be inadequate for towing a 989 in either configuration. As you stated, without weight transfer, the trailer would push around a Deuce pretty bad. This M989A1 trailer and it's cousin, the M989, were made with the HEMTT in mind. I can't find any pictures where the military pulled the HEMATs with anything else but a HEMTT series truck. I think it best to pull one with either a 5 or a 10 ton with a cargo bed, the 5th wheel trucks lack the weight in the rear.
The only reason my F450 can pull as much as it can, comes from the added traction from 5000+ lbs of weight transfered from the trailer to the truck. A HEMTT weighs nearly 4x the HEMAT and even loaded, the HEMTT weighs 7000 lbs more. Plus, how often are you going to have a loaded trailer and an empty truck. Most likely they would both be loaded and at max weight for each, the HEMTT would out weigh the HEMAT by a better than 2:1 margin.