Holes would need to be drilled through the spring tips in order to use them... but they might be pretty nice. On the other hand i'm skeptical, since I've never seen an OE spring with such inserts. I definitely wouldn't want to put anything between the centers of the springs (except maybe steel strips), lest it wear and loosen my u bolts.
My new springs from Eaton came with them. I have also run the TEFLON type full length liners with no problem. https://www.speedwaymotors.com/shop/street-leaf-spring-pads-buttons~65544-1-31215
Drilling in to leaf springs is not an easy job, the spring shops punch press the holes. It makes for a smoother ride and much quieter. I say it well worth the trouble to have them or the liner installed. Never had a issue with the liner strips or u-bolts coming loose. I went with new springs so I could get custom spring rates for a smoother ride.
I used Teflon liners from Speedway: Speedway Leaf Spring Liners Part # 91033037. i didn't need to drill any of the leafs, just cut the material to length and center a hole over the spring pack bolt and assemble the springs. Very easy modification, allows the leafs to move easier and took care of the squeaking.
Come,Bleed or Blister somethings got to give!!! Q:"What yah runnin" A:"3/8 drive Black and Decker aquarium pump motor" (the movie HOTROD)
59' Apache 31, long term project (30 years and counting)
Cool, thanks for the comments guys! I'll go ahead and try out tip inserts. It looks like the only ones available online are high durometer polyurethane... probably fine, but right now I'm planning to turn my own out of UHMW for maximum durability & minimum friction. I heard that drilling spring steel is reasonable with a masonry bit... we'll see.
Sounds like the full length liners are also tried and true, but since this is for the front springs on a 4x4 axle (will get beat on a lot), I'll avoid sticking extra layers under the u bolts.
So, I bought a 2" stick of UHMW and made some discs. I was too lazy to drill holes in the leaf springs, and I didn't see a good way to do that over the retainer rivets anyway. So I welded some washers on instead.
The washers poke up 1/16" and the plastic discs are about 0.16" thick. That means the plastic can wear down 0.1" before metal rubs on metal.
My pads are way thicker than typical pads... I wonder if that has any consequences?