The Trek Y66 I'm currently riding is equipped with 9 speed DA 7700. The crankset (DA 7700 53/42) is a bit worn and since I live in a hilly area am looking to switch it to something more compact, 52/36 or 50/34 would do. Any suggestions as far as replacement brand/model? Not sure what is or isn't compatible with my current DA 7700 9 speed set up. Doesn't have to be DA level and I'll probably try to find something off the used market. Thanks in advance.