The Mark III is just below the Joyrider in Schwinn?s hierarchy of bike trailer / stroller conversions . The size, weight, and features of the Mark III are essentially identical to the Schwinn Mark II but with one major exception: the Mark III comes with a 16? fixed front wheel kit, making it a functional jogging stroller in addition to its primary purpose as a bicycle trailer. The Mark III also comes with different fabric colors than other Schwinn bike trailers. Both the Schwinn Mark II and Mark