I understand frequencies and dampening due to my training in the field. A little 'post high school' physics is all it takes. Or about ten minutes of reading will do also. And neither is as good as having tried out just about every combination at the track and on the street. It's not complicated and it's easy to understand that polygraphite works better than solid metal for these bushings.... It was a big and great thing when they came out with plain poly for it. Now you have the graphite added to take away the squeak. It's a good thing. Been there and done that. The solid bushings are just for racing/racers. They are great for that. For your Sunday cruiser, keep your polygraphite in the mix.