I highly recommend Yakima brand bike racks. The one that we have can hold up to 4 bicycles. It also comes in a 2 bike configuration. The lock is built into the rack and wraps around the bikes and then secures back onto the rack itself. It works great and keeps the bikes nicely secured. If you are going to use a bike carrier for a female type bike frame you will also need to purchase a crossbar to attach from the handlebar post to the seat post. This will be the part that will attach to the carrier. (Note this when using the lock so the bike will not be removed when only the crossbar with the lock). We also have a hitch lock so the carrier is secured to the receiver on the vehicle. Another great thing about the Yakima is that the arms that hold the bicycles fold down when not being used to allow easier backing clearance. Hope this helps.