urethane vs polyurethanev vs rubber bushings difference

[68 SuperRam]

Can someone help educate me more on what is the difference between urethane vs polyurethane vs rubber bushings?

Also would be curious to know what products / grease can be used to install these types of bushings?

I was told that Wd40 Silicone can be used for rubber bushings (body mount) and suspension parts to help against cracking / drying out.

For polyurethane - Energy Suspension has a grease that is used for bushing installation.

What about urethane - was told that dielectric grease can be used for installation.

Thanks

[Pedigry]

afaik, rubber is softer and will flex more. Guys make the transition to poly bushings to tighten everything up, whether its body mounts, A-arm bushings or the bushings in your sway bar. The only down side I have heard is that they can be noisy. My daughter has a 350Z with poly swaybar bushings and they squeek. They just need to be lubed more. Poly will also, because they are stiffer, transfer more energy. IOW, they will make the car ride harder or transfer more road noise and/or chassis noise into the cockpit. It's a tradeoff, like most things. They may be great in the suspension, but you may prefer rubber in the body bushings. Just think about where you really want that extra firmness.

[68Formula]

Technically urethane and polyurethane are different. "Poly" = many, and polyurethane is really made up of many urethane compounds linked together to create desired properties. But in the suspension component world I believe they use them interchangeably (it's all really polyurethane).

In general, compared to rubbers, polyurethanes are higher shore harness, making them stiffer (less deflection). I say "in general" because the properties can be varied within a certain range for each of them. Polyurethane is also stronger, and more resistant to the elements. So on the plus side, they will improve handling and longevity; but at the cost of potential noise and ride quality.

For grease, just use whatever is recommend by the manufacturer.

[jaybee]

Recently I discovered another option out there. I don't think I'm allowed to post the manufacturer here, because they're not a pro-touring.com sponsor/participant, but it's an interesting bushing construction. Inside, the usual steel sleeve which surrounds the bolt to prevent crush. That's surrounded by a Delrin sleeve to prevent the stiction and squeaking common in polyurethane bushing. Around that, polyurethane to lower the durometer (hardness) of the overall assembly and allow a small amount of flex for things which aren't a perfect pivot. They aren't available in a lot of external diameters, but they machine the Delrin sleeves for 1/2" or 9/16" bolts and will build them to custom widths upon request.

[badbu68]

I've heard people wrapping poly bushings in a single layer of teflon tape and then grease over that, eliminates stiction and no squeaks.

[dhutton]

Recently I discovered another option out there. I don't think I'm allowed to post the manufacturer here, because they're not a pro-touring.com sponsor/participant, but it's an interesting bushing construction. Inside, the usual steel sleeve which surrounds the bolt to prevent crush. That's surrounded by a Delrin sleeve to prevent the stiction and squeaking common in polyurethane bushing. Around that, polyurethane to lower the durometer (hardness) of the overall assembly and allow a small amount of flex for things which aren't a perfect pivot. They aren't available in a lot of external diameters, but they machine the Delrin sleeves for 1/2" or 9/16" bolts and will build them to custom widths upon request.
No need to keep it a secret. Not breaking any rules telling us who it is and posting a link. I am curious.

Don

[jaybee]

No need to keep it a secret. Not breaking any rules telling us who it is and posting a link. I am curious.

Don

Very well then, here it is. https://www.cheperformance.com/pages/poly-delrin-control-arm-bushings

They're a small, family-owned business, seem to be well thought of in their chosen market, and it's a product I think could be useful in a lot of circumstances.

[David Pozzi]

Urethane is prone to higher friction under load. It will make you car ride like it has stiffer springs. If it isn't greaseable, forget it. Silicone grease is used on it.

Rubber is good on a street driver but the current stuff seems to not last as long as OEM rubber bushings. Rubber deflects and remember the Camaro was designed for 5" wide tires and low cornering loads. I think there is a rubber lube available. I'd be careful on what you put on it. Most sprays are bad for rubber.

Delrin is good stuff. Low friction, long life, it transmits road shocks more but only like 10% more according to what I've read. Use a high quality synthetic grease.

[pitts64]

I had a 3900 pound 64 Bonneville and put solid rear control arms with poly bushings in them. I was at the beginning of all this. Wow did those control arms screw that cars ride and handling up. I later found out from early sixtys Nascar racers that those factory control arms were suppose to twist along with the rubber bushings. Those guys use to drive those cars at 120-160 mph for 500 miles!

What I did by swapping those poly bushed control arms without a way to lubercate them was lock that cars four link up, and every now and then I would go thru this wierd turn to get onto my street and the cars suspension would bind or lock up, then right at the end of the turn, it would let go and it felt like the cars weight would shift directions.

The issue was I didn't correctly lubercate those bushings. The poly bushing is a bearing that rides inside the control arms end links.
Later on that same company had grease joints all over those control arms with small tracks cut into the bushings so the red grease could get to all locations.

I found Currie Johnny joints and made four control arms out of them. When I removed the poly control arms the bushings fell right out they were about 1/4" smaller then when new.

My brother has polys on his 68 GTO, he lubes them every 300 to 400 miles. He loves them.. But you know those GTO guys, he rairly takes it over 30 MPH because it's some kind of rare Ram Air II. When we leave car cruises, those old dudes in those Model Ts pass us LOL..

[pitts64]

Dave is correct (as always). Use the special red grease on Delrin. I have Delrin in all my front and rear control arms on my 69 el Camino. Last grease job, my gun ran out of NAPA grease, so I used this tube of red grease that I won at a car cruise.
It made a big difference in how my whole car suspension was moving. This stuff is definatly made for Delrin coated spherical joints. I noticed my car rides alot better. Its like the first movement of the joint comes sooner because of less friction (maybe?).. I also noticed the pump on my 60 year old gun was easier.

[tmcmillan5]

Do you have a name or part # on that red grease ?