Hollywood...I did several 500 mile rides with the 21" and with a passenger. It's hard to describe exactly and it's only my opinion, but I can't say there were ever any real "significant" comfort issues. The bike always tracked real well down the straights and corned well also with a new learned lean angle. The area most concerning to me was the decrease in stability at low speeds with a passenger, (coming to a stop, slow speed maneuvers, and a bit more rigid ride.) You sit up higher and I didn't feel as planted on the ground as I did with the 16's/18's. I kind of liked the increased "raked" feeling at first, and then it started to become kind of annoying and tippy. All in all, I did like the 21" though. I just like the 18" better. I don't think you'd be unhappy on long trips. A lot might depend on your size and your passengers. One thing I really do believe is that HD designed the 16/16 for a reason and they ride and handle great. I honestly don't believe that handling actually improves a great deal if at all. The 16's handle great. I will say that the ride is more comfortable and plush with the 16's by a fair amount. Bigger wheels on baggers IMO are to show off the wheels and for looks. Just my opinion. A lot of folks swear their bikes handle better with the bigger tires. I say they don't handle any worse, cause the 16's are very good in both comfort and handling.

 

Thanks for the info, I have been tossing the 21 or 18 around for a long time. With the amount of $$$ involved I just want to have it be the correct choice!