Hum, I think a free swivel wheel would only work for very cheap designs. If you're not convinced, you can search for 3 wheels vehicles on google image [1]: none

Hum, I think a free swivel wheel would only work for very cheap designs. If you're not convinced, you can search for 3 wheels vehicles on google image [1]: none of the vehicles there have the 2 wheels + 1 free rotating wheel design that you recommend. https://www.google.com/search?q=3wheels&biw=1673&bih=1124&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiKz_yL-JfKAhVIJR4KHdy3AxwQ_AUIBygC https://www.google.com/search?q=3wheels&biw=1673&bih=1124&so... Edit: actually, some baby carts have it .. alright http://www.aliexpress.com/store/product/EMS-Free-shipping-Good-Quality-Perambulator-Baby-Stroller-With-3Wheels/711381_1538853521.html http://www.aliexpress.com/store/product/EMS-Free-shipping-Go...