Car bike racks and small kids bikes often pose a problem. The main reason is the horizontal carrying space is too short or cramped to fit on the mounting point. But you can purchase an adaptor bar for kids bikes from most bicycle stores. Apart from being creative with this (note, always have the great bulk of the bike below the clasping point of the rack) the only alternative is to purchase an adaptor bar. These cost around $20-40 at most bike stores and fit by attaching to the handlebars and the seat post. You may need to lift the seat post a little but once attached this usually gives a child's bike enough space and clearance to fit on the bike rack. Please make sure to tension the seat post in place! We've spotted a number of ways to attach kids bikes to cars whilst out and about which you can see here.