So I was thinking about doing that duathlon in central park at the end of march as a short term goal for the time being and then have the triathlon in june as the long term... I want to get a road/triathlon bike for the one in june but im thinking about using the mountain bike in the duathlon. I believe they usually have two classes of bike you can enter. skinny and fat tire. I need to look into it but if you want to do both, i think its a great idea.