I have a Trek 3700 that has screwed threads for the pedal. I tried using a tap and die set on it and they still wouldn't thread into the arm. So I am thinking about getting a new crank set and need to know what to look for and what gearing is going to be the best. I ride alot of trails but nothing Uber aggressive. So I am wanting to hear peoples suggestions what is on there now is 48-38-28 (I think I counted them correctly).