Hey guys, my rear tire was down to 4/32" or so and noticed the handling wasn't very crisp and when really pushing it the bike felt unstable. I was at Sacramento HD where I had my rear replaced with the stock Dunlop. I was bs ing with Monty who's their foreman and who's been there for 30 years (this guy's the ****). Prior to the tire replacement, he lifted off of the jiffy stand, holding the handle bar with one hand, grabbed the backrest and jerked the bike back and forth laterally. He said look at the tire. All of the flex of the bike jerking side to side was in the sidewall. He was telling me he runs his tires at max pressure and that all the flex from running low pressure breaks down the cords in the tire which causes much of the sloppy handling in the baggers. All I've got to say is what a difference with the new skins. I've averaged around 36 psi, I'm keeping them at 40. I'm on my 4th rear tire averaging about 8 to 9k depending on screw failures and stuff like that. Interesting. I wonder how well a lower profile sidewall tire would work.

 

I put a different wheel on the rear of my 09 road king. It had a few thousand more miles than my original tire. I thought something was loose when I rode it the first time. I checked, everything looked OK. Kept riding. Seems OK now. So I think you are on to something. The differnece in mine would probably never be noticed as the tire was wearing down, only with the sudden change.
Same tire, dealer installed so it seems the only variable was the relative amount of miles on the two tires.

 

A worn rear tire on a bagger will always make it handle like crap. Put a new tire on and it will track like a new bike. And I always run my tires at max pressure on the side wall.