Hey Shoeless, I used that polyliner on my 59 1/2 ton, worked Great. Still rides hard, but not as hard as it did. I would have to say it was a 80% improvement over stock. Course, the new shackles and bushings had to help.
About 4 years ago I took a long (60) mile jaunt into the desert to camp with freinds. Road was rough and one of my leaves cracked a few days later. I replaced both of my front springs with brand new ones from EATON, and I specified stock height and number of leaves. I did have them upgrade to "rod-ride" springs which uses the teflon buttons to reduce friction. I can honestly say that the new springs with teflon buttons rode no better than the 40 year old springs with polyliner.
My 5 cents.
Curly
