Thread: Do not use poly bushings with polished dog bones?

Can someone explain this to me? Why would the poly bushings cause more vibration with these? I'm gonna be getting poly bushings but not polished dog bones but saw that when looking on the site and it made me curious. Don't the poly bushings cause less vibration since they are a harder rubber?

Poly bushing cause you to feel more vibration because they are harder, so they give less. Then they transfer that vibration into the frame of the car. The softer rubber with the hollow sides like the stock ones are designed to give and wiggle to absorb the vibration of the motor so you dont feel it.

Alright thanks that makes perfect sense. So why do the poly bushings cause so much extra vibration in the polished dog bones it's recommended not to use them together?

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They don't actually clause more vibration, they just transmit more to you. Since the motor vibrates a bunch, GM installs rubber mounts to absorb those vibrations. People upgrade to Polyurethane bushings when the rubber wears out, or they want to do stuff. You will feel more vibrations, most noticeable at idle and just off idle.

Who says that? Its same amount of vibration in regular dogbone with poly mounts as a polished one with poly mounts

Originally Posted by 91parkave

Who says that? Its same amount of vibration in regular dogbone with poly mounts as a polished one with poly mounts

ZZP actually does, and Im honestly not sure why.

Upgrade those rusty old pressed sheet metal stock dogs bones with stronger billet aluminum pieces. They come with new rubber bushings installed. We do not offer them with the polyurethane bushings installed because they will cause too much vibration.

I've never heard of anyone saying you can use (or shouldnt use) poly bushings in the billet dogbones. Only thing I can figure is that somewhere there is a weak spot that with enough prolonged vibration could cause a shear in the aluminum, thought I've never seen it happen.

I've had both and not noticed or felt more vibration , its just a show piece and by virtue of being billet its not ever gonna break.

Billet is a lot tougher by far, but when it does go, it shears. I can't see the dogbone ever failing though.

hmm that's kinda what I was thinking. I figured it had something to do with the material they were made out of but wasn't 100%. Maybe it's just one of those disclaimers they have to use to not get sued.

Wbody store who sells billet bones come with a poly round bushing and I have that along with the billet bone and poly square bushings

Ive had all poly bushings and engine/trans mounts for a while and just recently installed the billet dog bones.. i didnt notice a difference in vibration at all

I had installed poly's on both the front and rear of the dogbones and found too much vibration as well. What I chose to do was reinstall the stock rubber rear bushings (round) in the dogbones and was perfect. The flex was eliminated from the front bushings by using the poly over the stock and the vibration no longer chattered my teeth