>>1736287Do you have rack mounts? If not you'll be looking at clamp-on racks, either onto the seatstays or the seat tube. If you do have mounts, that opens up options. How much weight are you looking to carry? Are you wanting just a milk crate on the top, panniers on the sides, or both?
Off the cuff I've been very happy with my Axiom racks (pic). I've had them up to about 60lbs on grocery runs multiple times, and they hang really far back so I can run large panniers without striking my heel on the bag.