Why not use bushing grease on a-arm bushings? Options

[Tdskip]

Hi guys - I know how it is commonly done including Ian’s great video. Is there a reason why not to use bushing grease instead of softsoap?

So you want the bushing NOT to move or rotate ones installed? I assume that is a reason but wanted to ask.

Thanks.

[Mikey914]

EPDM that was used on the OEM parts has stood up for much more than the 30,000 miles. I'm just thinking that it will be good for another 20 yrs minimum.

Is the Poly going to outlast the natural rubber, yes, but will require more maintenance. Is there any data to show the material will offer a superior ride?

We are also using a compounded rubber that is at the minimum equivalent to the OEM in performance.

The ultimate design would be to go to a roller bearing assembly.

[Superhawk996]

The ultimate design would be to go to a roller bearing assembly.

Nope. Not for street use. It would be awful. I've been in a race cars converted to spherical bearings to decrease complicance for improved handling at all cost. The ride degradation is brutal. The road noise inside the car increases dramatically. OK for a a race car, but, I'll just say that I have no desire to subject myself to that on the street.

The other thing that hasn't been talked about with a move from rubber to an actual bearing is the increase in impact loads transmitted to the body attachments. Rubber does a great job at damping damaging peak impact loads. Hard materials like Delrin and spherical bearings have no ability to damp impact load and they result in "spike" loading. This results in either quick wear and deformation of the Delrin or brinelling of the bearing. Once you have some relative movement between the two parts as the Delrin deforms, the "spike" loading gets even worse. Worst case can lead to ovaling of the body mounting points over time. The brinelling of a roller bearing would be very fast due to the limited range of motion and high point loading. Pretty soon you would have the rollers sitting in small pockets in the raceway and a very rough motion as it rotated. Likely would break down the rollers pretty quickly.

Agree completely that the EPDM rubber bushings will hold up over time. Just look at how long OEM rubber has held up not only over time but also miles.

The key is to use quality rubber designed for use as a bushing which isn't as simple as it seems as I'm sure you're aware. As others have mentioned, low quality (improperly spec'd rubber compound) rubber bushings can have a very low glass transition temperature that leads to craking of the rubber in when temperatures dip below as little as 30F. There are a variety of "summer" and AX tires that will crack if rolled under load in 30F weather. In this case, the cracking isn't "poor" quality rubber, but rather rubber that was never intended to operate under that temperature vs. load condition. All rubber is not the same.

Again I'm not oppposed to Poly bushings for certain applications, but, let's not kid ourselves. Poly does not come without its own trade-offs. Let each person decide with eyes wide open. The Poly bushing aftermarket spends a lot of money advertising in the magazines and they only give their side of the story.