The SeaSucker Bomber Three Bike Rack held onto your vehicle with vacuum cups - that's right, vacuum cups. The rack has five different vacuum cups up front with a rated pull strength of 210 pounds each. These vacuum cups will hold your bike securely on top of your vehicle on any non-porous material. This bike carrier only weighs 17 pounds - so it will easily fit into your suitcase when you travel to your biking adventure. This is a fork mounted carrier, and comes with three Huske Universal Fork Mounts. If you are looking for specific axle sizes, consider ordering the MAX version which includes the 9 x 100 w/ skewer, 12 x 100, 15 x 100, ans 15 x 110. There are three additional vacuum cups for the rear wheels. The fork mounts can be moved to different positions so they do not bang against each other for transport. The axle adaptors snap right into the base that comes with the rack. So, gather your friends & get back to nature with the SeaSucker Bomber Bike Carrier!