When I bought my bike the salesman told me to run about 20-25 psi solo and bump it up to about 35 psi with the wife on the back. I havent "experimented" much outside of this frame, but it seems to be working great. Very comfortable.
I ride an 09 Classic with the Street Glide lower shocks,and the tour pac removed.I'm around 170lbs and ride solo all the time.I'm running around 20-25lbs,and boost it to around 30lbs or so when on a trip with the bags loaded and the tour pac on.
I didn't know till I got my 2010 that there were two different shocks. My 05 had low pressure shocks and never bottomed out with 35 psi. But, this new bike has high presure shocks, and bottom out all the time with 35 psi. I'm talking two up on the old bike and single up on the new. I run 40 psi on the new with a rough as hell ride but no bottoming out.
Ok, I must be an idiot but.... I cant find the input valve on my 08 road glide. Have had the bike for over 18K. Once I find the ^%*(( thing it will be interesting to stiffen up the ride with a few more lbs (if any air is in there) of pressure.
While setting on the bike, it should be behind the left saddle bag. I have to open the bag to get to the valve stem. You may even have to remove the bag to see it. If so, while its off, relocate it for easier access.
I run mine at 45 for both of us with luggage - bike handles superbly with this setting. I've ridden a few demo bikes which weren't set up correctly and was surprised just how significant it is to get it right.