A few yrs ago, I rode a RoadKing with a 21. It rode fine.
It steered a little slower than other touring models I've
ridden. Only noticeable at low speeds.
I have a 21 on my deluxe. The bumps may be felt a little more but other than that I feel no difference. No mods needed and you cannot beat the look though......
yeap, i did the 21" front rim on my deluxe. i noticed a difference right away. the ride is a bit harsher and you have to work a little harder to steer the bike. my bike is a 2005 so the axle is smaller then yours. i had to use axle reducers to make them work. but man do they look good !! every place i go with this bike everyone comes up to me and starts talking about the wheels.....