Has anyone changed the stock front wheel to the 19" or 21"? I was wondering how the front end handles after the change?

 

A 19" with the stock Harley size of front tyre has a similar rolling diameter to your current front wheel. In fact the 16", 17", 18" and 19" stock front wheels are all very close in size, due to using reduced sidewall heights. They may ride slightly differently, but shouldn't affect anything adversely. 21" wheels are a little larger in diameter and may have more affect on the bike, although there are plenty of members with them.