Don't use a 21" Wrapper fender with a smaller wheel
I have a 19" front wheel on my Road Glide. I wanted one of those cool wrapper fenders from Klock Werks or FBI. Since they don't make one for a 19" wheel, I thought a 21" would be fine. I was wrong. Too much gap in my opinion.
Oh well, someone will get a good deal on a used fender...
If you had a 21" rim, wouldn't you have a lower profile tire to go with it and make it roughly the same overall height anyway as the 19"?
He has a fender for a 21"...with a 19" wheel.
A 21" wheel with the standard tire will fill that fender up, thus it'd be taller.
A 21" setup is approximately 1.2" taller than stock.