Poly or Rubber?

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pacuda59

pacuda59

pacuda59
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About to upgrade the brakes to BBP/Disc so I thought I'd do the suspension at the same time. I'm planning on keeping the /6 and using the car for motoring and not speed. Should I go with rubber or poly bushings?
 
Your choice. Personally I prefer poly but even in most poly kit the lower control arm bushing is rubber. You can get a poly in the lower you'll just need a grease able shaft down there.
 
i have stripped lots of these old Mopars and although the rubber was showing its age after 40+ years,most of it would still function O.K.
...rubber probably gives a better ride
...some of that hard plastic doesn't last too long.
 
I usually use rubber. I didnt care for the fit of any of the poly dust boots, Had issues with poly lower control arm bushings so the only ploy bushings I ended up using were the upper control arms and the Strut rod bushings
 
I've done a couple in poly and a pair in rubber. The rubber bushings are fine for street and occasional track use. How old is your car? Have the bushings been in there the entire time? I expect new rubber bushings will give the same kind of service the originals did.

Either way you decide to go, look at this chart. The max street performance settings work well with a /6 and rubber bushings. I used it when I rebuilt the front end on my 73 Dart Custom. It transformed the way the car drove. Turn-in was sharper and the steering didn't feel quite as over-boosted.
 

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Take a sour cream or yogurt container and put a piece of melon or fruit in it put saran wrap over it tightly using a rubber band or hair tie then poke some wholes in top they get in but can't get out
 
I rebuilt the front end of a 68 Barracuda that I drove everyday with poly. I had to rebuild it again 3 years later (no thanks to the rough bumpy streets of Detroit) and went back to stock rubber type. The rubber stock style lasted longer and was more durable than the poly, and gave a less harsh ride.
 
krazykuda said:
Hey Cliff, I think you posted this in the wrong thread.

Try the little black knats in my kitchen thread for this:

http://www.forabodiesonly.com/mopar/showthread.php?t=247468
Click to expand...

LOL

The polys do transmit more harshness into the ride. My experience was that with the 235/60-15s on the Demon 318 on rubber, I could feel the front end twitch through the steering just a bit. The /6 Custom on rubber bushings and 205/60-15s do not exhibit this. When I put the polys in the Demon, the twitch disappeared. It now steers better without and twitchyness.
 
2 Darts said:
LOL

The polys do transmit more harshness into the ride. My experience was that with the 235/60-15s on the Demon 318 on rubber, I could feel the front end twitch through the steering just a bit. The /6 Custom on rubber bushings and 205/60-15s do not exhibit this. When I put the polys in the Demon, the twitch disappeared. It now steers better without and twitchyness.
Click to expand...


yes, some tires may dampen some of the harshness. That is a good point.

I had the same tire/rim combination for the whole time and mine was based on observing just how the two different bushings affected the ride. The bumps were harder with the poly's and they did not last as long as the stock rubber style. I have literally gotten flat tires and bent rims from the potholes in Detroit when I was living there, even with other cars. Their roads suck!

For a daily driver/cruiser, I would go with stock rubber style.

I would only use poly if you plan on road/ralley racing and need the stiffer handling.
 
Ive read several threads over the last couple days as I plan to re-do my LCA's and/or Kframe tubes. Its interesting to hear the anecdotal evidence to each pro/con. Where one will say it failed early, another will say it lasts more than a decade.

Having done Urethane on my FWDs i have a hard time believing the rubber is the better choice for any bushing. It just seems like it would come down to costs/and difficulty to implement. Well that and there is at least a couple different urethane bushing designs. Ones that reuse the old pivot pin and the inner bushing shell and ones that require a new pin. Then there is some extra care required around the strut shaft...

Where as the OE style bushing is one piece. Push the old out, push the new in... simple easy and seems hard to mess up.

I'm leaning toward budgeting for Urethane with grease-able pins while trying to convince myself that the delrin is too extreme. :thumblef:.

-tro
 
o.e rubber is not actually a bushing.
..there is no movement other than to twist the rubber during suspension travel.
..the rubber provides some torsional resistance.
..tighten at normal ride height
 
pacuda59 said:
LOL.....thank you Krazykuda, I was about to swear off of my Saturday night martinis!
Click to expand...


It's the only logical place that I could figure that post would fit in. I had just got done reading it before seeing his post.

The question is: "How did he post it on the wrong thread in the first place?" IDK...
 
ir3333 said:
o.e rubber is not actually a bushing.
..there is no movement other than to twist the rubber during suspension travel
Click to expand...

whatchu talking about Willis? I admit i don't have one in my hand BUT.... is it not two shells of metal with a isolating rubber bush in the middle?

i get what you are saying, that the strut takes all the for/aft forces. But if the bushing is only job to twist, even more reason to make it a bearing surface. (urethane rotates does not twist).

Which leads to another question...How much fore/aft does the arc of the strutrod pull on the LBJ?
EDIT: searching... ;-)
 
I use rubber. The thought of having to grease all the control arm bushings in addition to everything else seems kind of nuts. Unless your doing timed events, I wouldn't bother with poly.
 
ir3333 said:
o.e rubber is not actually a bushing.
..there is no movement other than to twist the rubber during suspension travel.
Click to expand...

I'm going to stick my neck out here and respectfully disagree with these statements.

Rubber or poly in this application is indeed a bushing.

http://en.wikipedia.org/wiki/Bushing_(isolator)

Movement of the suspension pieces, especially when encountering sharp bumps or potholes, is not only vertical but also horizontal. IMHO, when the bump or pothole is encountered, the suspension deflects horizontally against the bushings (LCA, UCA, & strut rod) as well as vertically against the TB and shock. This horizontal deflection is what causes the bushing to get loose compounded by the natural deterioration of the rubber of polygraphite. It seems to me that this is supported by the anecdotal information provided by other posters about the premature wear of bushings in cold, roughly paved environs.
 
If I was to go with rubber bushings I would only use Moog parts.

On the other hand I have had a good experience with poly bushings. but it sounds like rubber would be good for you.
 
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