Do the IROs not have standard size eyes? Is that why you can't find rubber? Or is it a supply chain issue you are up against?
The IRO springs have 2" diameter eyes. Different than OEM.
If it is a matter of the size of the eyes I would call someone like National Spring or Deaver and ask them if they have information about which factory style rubber bushings would fit the IRO spring eyes (of course have specs in hand for the IRO spring eyes before you call).
That's a decent idea. I tried looking through the Dayton catalog but at 1,000+ pages of unsearchable pdf I didn't get far. I suppose I haven't put in the leg work to determine the size I need.
AFAIK, the OEM sizes are:
Front:
OD: 2.500"
ID: 0.563"
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 3.188"
Rear:
OD: 1.750"
ID: 0.563"
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 2.750"
Hopefully can find some that match those dimensions with a 2" OD. I was searching on TruckSpring.com, which has a decent search filter by size, but didn't find any that work.
I do think it is worth the effort. Unless you don't mind listening to squeaking bushings.
Thanks for supporting this. I thought everyone would say just go poly because its easy. The squeak isn't even the number one driving factor of me wanting rubber, although its up there. I can't wrap my head around the idea of a poly bushing being good for decoupling the springs from the body, and also handling the torsional deflection as well as rubber can. I would think rubber should ride better and flex better, maybe at the expense of shorter longevity.
The only downside I can see to rubber is how the inner sleeve is bonded to the rubber, so when a leaf droops it twists the rubber axially. I can't imagine they would hold up very well to that. I'd love to see a robust rubber bushing with good flex characteristics come to market, but I'm not holding my breath for any new leaf spring products.
I'd be very curious to try Orbit Eyes or another style joint in a leaf spring bushing, but I don't like how those style joints don't self-center. I feel there would be a big loss in lateral stability without that. I'm looking to get new shackles with these leafs and have been eyeballing Boostwerks' Comp Shackles with the Ballistic Joints at the frame side, but I'm not sold. My rig sees too many road miles to compromise pavement characteristics. I'm gonna send him a message to ask about his experience. I don't want to do a panhard or anything of that nature.