1 TDD 2 Punching power 3 Recovery/chin (Did not have a great chin but it was good) 4 relentless attitude/ stamina( he threw wild bombs but had good cardio for a guy carrying a developed gut)
This is true but you cant fault Chuck for that. Problem was UFC had alot of wrestlers back in the day and it was perfect for Chuck because of his TD defense. I remember his fight with Vernon White who was alot smaller but had his moments against Chuck.
I would say his take down defense, That allow him to keep the fight standing which and make his oppenent play his game. No one could take him down and keep him there.