On April 16, 2004, about 1900 eastern standard time, a Curtis-Wright Travel Air 4000, N6425, registered to and operated by a private individual, as a Title 14 CFR Part 91 personal flight, incurred damage while landing at Treasure Coast Airpark, Port St. Lucie, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The airline transport-rated pilot and one passenger were not injured, and the airplane incurred substantial damage. The flight originated in Lakeland, Florida, the same day, about 1750. The pilot stated that during rollout the "right wheel broke and directional control was impossible." He further stated that the airplane incurred damage to the lower right wing's three nose ribs, which needed to be replaced. The FAA did not respond to the scene of the accident, however, two individuals who reside at the airport stated that they were at the scene of the accident, and they volunteered information to the NTSB. These individuals stated that they 'walked" the runway", and noted the marks made by the effect of landing gear on the grass, and that there were no holes in the runway. They further stated that they believed that the landing gear wheel broke from what appeared to be excessive side loads imposed during what appeared to be the beginning of a ground loop during the landing roll.