Dave wrote on 01/23/17 at 05:22:56:
According to Gary_in_NJ.....the damping in the Progressive shocks might be too stiff for our light bike. Changing to lighter springs might not change the ride much.
I did the same thing on my Progressive 412 shocks that are for a Sportster......and I went to the lightest spring they make. The ride is a little better - but certainly not cushy.
The only data I could find on Progressive's website says that:
"444 Series shocks are available in 2 configurations: Standard (Up to 250 lbs.) and Heavy-duty (250+ lbs.)"
I have no idea what this means. What is the 250 lbs. relative to; the rider, the weight of the bike at the rear axle? If it's the rider, certainly the requirements for a 150-170 lbs rider are different than the requirements for a 220-250 lbs rider. Why doesn't this spec take into consideration the sprung weight of the bike itself?
Ruttly, I believe that your bike is modified and has a significantly lighter rear and the front:rear weight distribution has been moved forward. For your reference, my bike is running 80-100 lb-in dual-rate springs.
If you are having the springs changed, you might as well make sure that the damping (valving) is correct for the springs and expected rate of movement. If the damping has been set for a 500 lb Harley, the damping will be too firm (slow to react in both directions) for your modified 300 pound LS650.