SPL Monoball Bushings

[racepar1]

Originally Posted by ManoNegra

on the other hand, when they fail it can be ugly....

I've had this happen to me personally and on my buddy's S13, except on our cars it was both the trac arm and the ruca that broke.

As stated, urethane bushings are fine, as long as they're lubricated. Once they lose lube they bind terribly, squeak, and break shit. I recommend installing zerk fittings on any urethane bushing that you install on your car so that they can be greased easily and regularly.

As for the monoballs, the only issue is their service life vs the cost of replacement. Monoballs used for daily use will probably wear out in a couple years and require replacement. Replacing them won't be cheap. You can buy seals to try and limit the amount of dirt and debris that get into them, which will extend the service life. As for driveability the reduction in bind will likely result in a smoother overall ride, you'll just be able to feel more vibration and hear more noise since there is no rubber to dampen the vibration. All in all the monoballs are the better choice as long as you can afford them.