Thank you for your answer. 13-28 cassette do you feel big gaps bettween the gears or not? I mean some people want 12-23 cassette because say is keep good cadence. But me i say you think good 13-28 is much better. i replace tires in one man bike and had 7 speeds cassette 12-28. this man have one bike cannondale R300 have the 52/42 and the 7 speeds cassette 12-28. I have the same bike but mine i buy from pawn shop. the man bike have original wheels and groupset. My bike had different wheels and i change the crank to 53/39 and i put 9 speeds cassette 12-25 but now i am thinking put 13-28 cassette. 53/42 crank is working better for you? is better than crank 53/39?