I'm running the stock 21" tire/wheel, I'm thinking of changing to a 19 or 16", I've heard different stories as to if
either of them can be laced up to my existing hub ?

Can either of them be ?
Any experience whith either one ?

p.s. my reason for doing this is for handling, rough roads here, lots of cracks. I think the 16" would be a smoother ride than the 19" but the 19" has a similar to the 21"

By smoother ride, I'm assuming you're talking about increasing the sidewall thickness? I'm thinking that won't help much.

Why not just see if they make softer springs for the front forks, or possibly change the oil to a heavier weight?

If I were you I would try to find an entire front end off of a Fatboy, or Heritage.....it would bolt up to your neck perfectly. All you might have to change out is your cables, or brake line. Check on eBay....

FBR :cool:

Smoother ride due to the payment cracks, the thinner tire
seems to follow them more.