Dyna Glide ModelsSuper Glide, Super Glide Sport, Super Glide Custom, Dyna Glide Convertible, Super Glide T-Sport, Dyna Glide Police, Dyna Switchback, Low Rider, Street Bob, Fat Bob and Wide Glide.
It can be done, but you'll need new triple trees, axle, spacers, and bearings. Have you considered getting the stock wheel relaced, that is the most economical way to put a 21 on your bike.