Rubber or Poly spring bushings?

[Masher]

I am having a local shop build me some new rear springs and he says he only puts in rubber bushings and doesn't reccomend using poly bushings. I thought the poly's were better and gave better flex but may sqeak a little. What does everyone think? I have poly bushings in all my springs now with greasable bolts and have not had any problems.

 

[dyeager535]

Poly gives worse flex, talking solely material. It's harder, deflects less, thus less "flex".

Now, to complicate matters, if the bushing doesn't flex, then something else must. If the "weak" spot is the springs, then they must flex more to absorb what the bushings won't. Or the shackle's do. Or the frame does. Etc. But flex shouldn't change actually, unless there is binding going on that is great enough to withstand the load.

Ideally your weak spot would be the springs, however the load on the bushings is not straight up and down as the wheel articulates, so the springs would have to twist to absorb flex that the bushings can't.

 

[Masher]

Thanks for the info. So what are your thoughts, which are better to run? Rubber or Poly?

Thanks

 

[dyeager535]

Poly seems to hold up much better for folks that wheel. OEM rubber on vehicles that aren't driven hard lasts for decades.

I think it's a tradeoff. Last I checked poly was far cheaper than OEM rubber. Rubber bushings don't need lubrication.

If the guy building them says he only uses rubber, I say let him, just make sure he understands your reservations and stands behind his product.