A hitch rack for bikes will require a hitch or receiver and these come in 2" and 1 1/4." Most cars and trucks do not come with a hitch receiver, unless this was a purchased option, and you may have to purchase it and have it installed aftermarket. 2" is the most common receiver type (and is what most trailer hitches require), whereas 1 1/4" receivers are generally for lighter accessories such as hitch racks for bikes. It is important to note that not all car hitch racks are made in both 2" and 1 1/4" receivers; however, many are "universal" in that they can accommodate both sizes with an adapter.
