Originally Posted by collegeskier

30-32 is give you 0.94 wheel revolutions per pedal turn whereas you get 0.87 for 20-23. That is a difference but it is a much cheaper option and will probably work better if you want the same gearing you would need a 34.5 mathametically but I would switch out the cassette, and if you want the ease for climbing and are itching to spend money get the tools to change the cassettes out then you have have the best of both worlds depending on what you need.