Keep in mind the street glide is lowered by approx 1". When comparing to the Electra Glides, rear shocks travel is 3", front travel is 4.6". So to say the Street Glide has a rough ride is correct. The springs need to be very stiff to not allow bottoming out. So maybe a pair of rear shocks from a Electra Glide to start with and then maybe change fork springs. You could also try a Electra Glide seat also. I suspect the proper air pressure is in shocks and tires are correct.
Also check this thread posted recently for more advice :2009 Street Glide shocks??
