Thanks for all the help, guys. My next question: is it even worth it to try such an incremental change, or should try a 32 or 34 first? I feel like I'm exerting too much energy powering up any grade >6%. I see guys on 34-36 having an easier time at it. I want to change my cassette not because I want to keep up with the Jones', but because my legs feel exhausted by the time I plateau.