Polyutherane vs Rubber bushings

[HappyGilmore]

I just did the bushings on my White CB back in May and had them replaced with Moog bushings. My Blue CB on the other hand is in need of new bushings. I have been on TASAuto lately they have poly bushings that I think would be better than the rubber ones. I would like to know the take of those who do have them and I know how it is when you don't. I am also aware that rubber does in fact wear out faster than poly does. I would like to get this information from a source I find valuable so, of course I come to the number place for that, CB7T. Thanks for the help in advance.

Happy

[GeoffM]

Poly is louder, harsher, and requires greasing every year.
It gives you a much firmer ride, and increased handling.

[mndude07]

Poly bushings do not make the ride more firm themselves. They are stiffer and have less friction. Imagine the oem rubber bushing being replaced by a pivot point with infinite stiffness and zero friction. The control arms will pivot easier, and all the force will be transferred through the shock and spring rather than some of the force being absorbed by the bushing. The larger the percentage of force you are transmitting through the shock and spring, the better..because you then have more control.

[accordztech]

in my z I went full poly. I havent regreased ANY bushings since it was installed at least 6 years ago. And I periodically rinse under my car.

If you do it right then it shouldnt squeak. I guess im just blessed LOL

[HappyGilmore]

Thanks for the input guys. I will be getting some then with that being said.

[xkjnboix]

Poly is louder, harsher, and requires greasing every year.
It gives you a much firmer ride, and increased handling.

i had form and function type 2's, F+R strut bars, and Acura CL F+R sway bars. Upgrading to polybushings just made the ride smoother IMHO. The difference was immediately noticeable. Hard bumps and holes in the road were completely absorbed by the full energy suspension black poly bushing kit which i installed myself.

Id highly recommend them to anyone looking to replace 20 year old rubber bushings any day. either way your car will be down for at least a day cause mostlikely you will run into trouble but why not replace them with something that will last a lifetime rather than just another 20 years at best.

[PR CB7]

^^^ what you felt was a difference from fixing wore down suspension parts

i just finished a complete suspension overhaul on the wifeys SE, monroe struts, new ball joints and new rubber bushings

i my coupe, i have F&F with everything poly except the trailing arm big bushing

polyurethane is a stiffer material, than rubber and it will make your car handle like you never would have imagined, but if you are looking to drive your car every day i wouldnt suggest it

the difference is night and day when i swap cars with the wife, dont get me wrong i like to take every corner that i can in my car, something the wifeys can't do

unfortunately there's no happy medium, rubber bushings will do just fine, you can also mix it up, half poly, half rubber

[mndude07]

This is all wrong. Suspension joints are loaded in tension and compression...do you really think such a thin joint would hold up to the vehicle's corner weight otherwise? If you increase the pivot point stiffness you reduce compliance....now pretend that stiffness goes to inifinity. Now the bushings absorb zero force, what member does all the force have to go through?

You guys have the correct conclusions but the wrong reasons.

The stiffer the bushings, the more force goes through the shock and spring...and that's a good thing. It makes the ride feel harsher because the impulse is being damped differently. Suspensions are designed with this in mind from the factory. If they were designed from the factory with poly or delrin bushings, and the ride frequency was desired to be the same, surely the springs and dampers would need less force to produce the same result.

Buying stiffer bushings will increase nvh as an "unintended function", and this is seen as a negative by car modifiers such as yourself that do not understand what is actually happening.

If you leave all else equal, maybe the poly will cause a stiffer ride, but it is really not to blame. For the most simplistic approximations, you should use joints with little to no compliance (sphericals) and make the assumptions that it is a frictionless joint in your model....then design from there. It is foolish from a performance standpoint to point the finger at the bushings when you can easily eliminate enough compliance to safely make that assumption.

My point is that no matter what, you should go with the stiffer bushings. If the ride is too harsh for you, then decrease the spring rate and/or damper force. This will result in more consistent and reliable control through the dampers and springs. It's all about reducing the number of variables you have.

[accordztech]

This is all wrong. Suspension joints are loaded in tension and compression...do you really think such a thin joint would hold up to the vehicle's corner weight otherwise? If you increase the pivot point stiffness you reduce compliance....now pretend that stiffness goes to inifinity. Now the bushings absorb zero force, what member does all the force have to go through?

You guys have the correct conclusions but the wrong reasons.

The stiffer the bushings, the more force goes through the shock and spring...and that's a good thing. It makes the ride feel harsher because the impulse is being damped differently. Suspensions are designed with this in mind from the factory. If they were designed from the factory with poly or delrin bushings, and the ride frequency was desired to be the same, surely the springs and dampers would need less force to produce the same result.

Buying stiffer bushings will increase nvh as an "unintended function", and this is seen as a negative by car modifiers such as yourself that do not understand what is actually happening.

If you leave all else equal, maybe the poly will cause a stiffer ride, but it is really not to blame. For the most simplistic approximations, you should use joints with little to no compliance (sphericals) and make the assumptions that it is a frictionless joint in your model....then design from there. It is foolish from a performance standpoint to point the finger at the bushings when you can easily eliminate enough compliance to safely make that assumption.

My point is that no matter what, you should go with the stiffer bushings. If the ride is too harsh for you, then decrease the spring rate and/or damper force. This will result in more consistent and reliable control through the dampers and springs. It's all about reducing the number of variables you have.

This is all true. However in my z, with the stock tires...the suspension feels very smooth, even though its lowered and with full poly bushings. You feel it more with the thinner series tires lol.

[onelivinlarge]

well im about to swap top poly on most of my stuff so we will see how it ends

[i want my cb9]

im pleased with my poly just about all round.

[Soufkackicustom]

I did all mine with the energy suspension black poly kit....they squeaked to hell and back. two weeks ago I shot everything with white lithium,and are as quiet as could be. my suspension was shot before the rebuild, so i cant tell you if it made a huge difference or not on the poly vs rubber issue