Proforged sleeved polygraphite LCA bushings!
I am sorry but I will have to respectfully disagree with you we sell both rubber and poly bushings The manufacturer that we work with to produce our OE bushing for the past 30 years does a process of vulcanizing the rubber in our bushings to the inner and outer sleeves. I have removed many pivot shafts from lower control arms over the years and when pressing them out the inner sleeve stay on the pivot shaft and piece of rubber stay vulcanized to the sleeve. I have also experienced this in many other applications like GM and Ford control arm shaft. Especially when the inner sleeve rusts itself to the control arm shaft.
The only way that oe does not spin is because it is vulcanized.
Thanks
James
Oh boy.
First, let me clean up my language here to eliminate confusion. I edited my previous post to reflect that as well. Vulcanization has
nothing to do with bonding the rubber to the shells. It's a process used to toughen the rubber. Vulcanization actually results in the rubber being more non-stick, as well as mechanically tougher. It alters the polymer chains INSIDE the rubber. So, yes, the rubber in the LCA bushings
is vulcanized. But it is
not "vulcanized to the inner and outer sleeves", meaning some kind of bonding between the rubber and the sleeves. Not the same thing at all. What vulcanization actually is-
Making Rubber Stronger: How to Vulcanize Rubber and
Vulcanization - Wikipedia
As for any kind of bonding, I think it's really clear there's no bonding between the rubber and the shell in the sequence of pictures I posted above. It's a mechanical fit based on the compression of the rubber. That's why the bushing is shaped like a barrel with several different wall thicknesses- it's designed that way to increase the force created by the compression of the rubber on the shell and sleeve. That's why the bushing doesn't spin, because the compressive force and friction between the rubber and sleeves create a force that is higher than the force required to flex, and even tear, the rubber. Which makes sense, because rubber is really great in compression, and really lousy in shear once you've gotten past the deformation stage.
Sure, you can press the pin out and have the sleeve stay in place, but that just means there's less friction between the pin and the inner sleeve than between the inner sleeve and the bushing. And the bushing was designed that way, which is why it isn't just shaped like a cylinder. But you
can press the sleeve right out of the rubber bushings. And as soon as you do that, the bushing will peel right out of the shell. Just like I showed in the pictures above. Pull one off the shelf and try it. The only bond between the rubber, the outer shell, and the inner sleeve is a mechanical one created by the compression of the rubber and the friction between the parts.