Rubber or Poly for a Daily Driven Corner Carving Street Machine?

For a corner carving street machine, should I go poly or rubber for LCA?

  • Rubber

    Votes: 37 43.0%

  • Polyurethane

    Votes: 49 57.0%
  • Total voters
    86
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GMachineDartGT said:
Forget both an use my delrin lca bushing. Quiet and stiffer than poly and does NOT use the outer shell. Corner carving and rubber dont go together, sorry.
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The outer shell is why I wouldn't recommend poly for most daily drivers. But that depends on how much effort, patience, resources the installers have.

The outer shells vary in thickness vs supplier and the way they were installed. I spent some time carefully smoothing and polishing the shell ID porting scrolls and small buffing attachment to try get the poly insert to slide in. Then it still didn't work. So next I very very carefully filed down the od of the poly insert. Made sure constantly measure the OD with venier calipers to make sure it was evenly round. Really could have used a lathe, but don't own one.

I ran a lot of the special snotty poly grease and if probably got 20K miles to this day on that setup I installed in 1997. And most of those miles where put on driving in LA city. West LA specifically. Mostly with .99" t-bars. When I go done there now with my 1.14" IMHO it's a little much. Fine in Simi Valley where I live now.

I'd go with Peters delrin setup if I replaced it now for what I do and where I live now. Better deal than that poly hit of miss stuff.
 
GMachineDartGT said:
Forget both an use my delrin lca bushing. Quiet and stiffer than poly and does NOT use the outer shell. Corner carving and rubber dont go together, sorry.
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I was actually looking at your bushings today. Can you explain them a bit more?

From what I understand, Delrin is a harder plastic that resists wear and is great for pivot points.

So why does it not require the outer shell and do you recommend using greasable pivot shafts or are those not needed? Can you explain how they are installed?

I'm guessing you pull the outer shells out of the LCA and then press these in and then insert the pivot shafts?

autoxcuda said:
The outer shell is why I wouldn't recommend poly for most daily drivers. But that depends on how much effort, patience, resources the installers have.
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Can you explain this a bit more? I'm not understanding. Is it because they are difficult to remove? As far as resources, I do have a 20 ton press in case that helps.
 
The poly bushing is really a plain bearing. And the shell is the race. And a bearing needs a particular fit between it OD an the race ID. Problem is the ID of the shell (race) is a moving target. It varies per supplier (Moog vs TRW vs Mopar vs ...). The ID of the shell can also change the way a person presses in the bushing. They can go in sideways, ballon inwards, etc.

The delrin bushing/bearing uses the Machined ID of the LCA. That machined ID of the LCA is much better than the stamped sheet metal outer shell who's ID was never meant to have any precision.
 
Many many years ago I went with the PST Poly Graphite front end on my Cuda.
Awesome!
 
JoesEdge said:
I was actually looking at your bushings today. Can you explain them a bit more?

From what I understand, Delrin is a harder plastic that resists wear and is great for pivot points.

So why does it not require the outer shell and do you recommend using greasable pivot shafts or are those not needed? Can you explain how they are installed?

I'm guessing you pull the outer shells out of the LCA and then press these in and then insert the pivot shafts?



Can you explain this a bit more? I'm not understanding. Is it because they are difficult to remove? As far as resources, I do have a 20 ton press in case that helps.
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I just installed a set of Pete's Delrin bushing's in a set of LCA that I'm rebuilding. The bushing is designed to fit in the entire opening of the previous rubber bushing, thus eliminating the outer shell. It should provide for a more linear movement I suppose, since it's all one piece rather than a bushing and a shell. The pin is pressed in with the bushing all at the same time as one piece.

Pete recommended using this grease http://www.jegs.com/i/Energy+Suspension/355/9-11104/10002/-1 and here's the pivot shaft http://www.americanmuscle.biz/34571_lower_control_arm_pivot_poly_p/34571.htm
designed for the new delrin bushing. That grease I guess has helped eliminate a lot of squeaking so a greasable pivot shaft isn't needed. I think Hotchkis ending up using it to eliminate some persistent noise problems.
 
tanis4457 said:
I just installed a set of Pete's Delrin bushing's in a set of LCA that I'm rebuilding. The bushing is designed to fit in the entire opening of the previous rubber bushing, thus eliminating the outer shell. It should provide for a more linear movement I suppose, since it's all one piece rather than a bushing and a shell. The pin is pressed in with the bushing all at the same time as one piece.

Pete recommended using this grease http://www.jegs.com/i/Energy+Suspension/355/9-11104/10002/-1 and here's the pivot shaft http://www.americanmuscle.biz/34571_lower_control_arm_pivot_poly_p/34571.htm
designed for the new delrin bushing. That grease I guess has helped eliminate a lot of squeaking so a greasable pivot shaft isn't needed. I think Hotchkis ending up using it to eliminate some persistent noise problems.
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Cool! Have you taken any pictures by any chance? Is is for a street car? How much do you intend on driving it?

Thanks!
 
JoesEdge said:
Cool! Have you taken any pictures by any chance? Is is for a street car? How much do you intend on driving it?

Thanks!
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Here's some pics of the installation, I intend to do a few things with the car, I'd like to be able to abuse it pretty hard on some back roads or up in the mountains, autocross or do some road course work. The car won't be a daily driver year round but I plan on driving it as much as can when the weather permits. If you intend on any type of performance driving or want something along those lines I'd just install these delrin bushings and call it done.
 

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tanis4457 said:
Here's some pics of the installation, I intend to do a few things with the car, I'd like to be able to abuse it pretty hard on some back roads or up in the mountains, autocross or do some road course work. The car won't be a daily driver year round but I plan on driving it as much as can when the weather permits. If you intend on any type of performance driving or want something along those lines I'd just install these delrin bushings and call it done.
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Amazing! Thanks that really helps. Your goals are pretty similar to my goals too. Those pics are great. Gives me a good idea of how it looks.

Right now, it's going to come down to budget. As far as the lower bushings are concerned I'm down to either PST or Bergman. I'll call Bergman today.
 
I say poly, your proposed set up is virtually identical to what my car has had for years except for the newer sway bar, bilsteins and delran bushings. Those weren't around when I put my car together but would use them if I get back under it. It has poly in the rear also.
Even without a sway bar and newer shocks I get miles of smiles driving with this set up.
A quicker steering box and welded/stiffened k-member and rip it!
 
FABO vendor PST kits are polygraphite.......if you are running bars that stiff with
a decent stab. bar, those or delrin would be OK. But the more your suspension
moves vertically (road cond. or suspension rate or combo) there has to be fore/
aft give in the lca & strut bush. because they are diff. radius arcs sweeping in two
different planes that diverge/converge a small amt. As Tbeast stated, the big bars
cut down on that,so you have more leash on rigidity. Elastomeric bushings are more
durable, unless you crank 'em down before droppin' the car to ride ht. & set your bar
adj., then they won't be there long. Greasable is always good...........
 
On a street car, I prefer a mix. Rubber in the control arms and poly in the sway bars. I am in the middle of getting all that together for my truck now.

The rubber in the control arms keeps road vibration at stock level while the poly in the sway bars really helps decrease body roll even more.

This of course is just my opinion.

RustyRatRod copyright 2016 all rights reserved.
 
Yeah, it sure does seem that opinions vary on this subject. I wonder if road conditions and type of weather affects those opinions. I know the type of driving and vehicle goals do.

Seeing that the Polyurethane (or Polygraphite) has overtaken Rubber in the poll, I think it's safe to say that it wouldn't be a horrible choice. I ordered my Sway Bar and it should be here by Monday. I already received new Moog lower ball joints, idler arm and 11/16" tie rods.

Next items in the will be LCA bushings, upper control arm, shocks and torsion bars. After all that's done an installed, I guess I'll have to see about subframe connectors.

I'm leaning toward the Delrin bushing, but I haven't ruled out the PST Polygraphite kit (yet).

With the Delrin bushing I won't have to fuss with the outer bushing shell and if I get American Muscles shafts to go with the bushing, then I won't have to fuss with an inner shell either. Seems like win-win there.

I'm going to the Muscle Car Nationals in Pomona, CA tomorrow, maybe I can talk to the AutoX guys there and maybe see products in person rather than on a screen.
 
If you have any question, find a friend who has the poly bushings everywhere in the front and see if they will let you drive it. It's not for everybody. Some like it, some don't. I know from a durability standpoint there's not really much difference between quality rubber versus poly. A good quality rubber bushing from Moog will last 40 plus years, especially as long as it does not get oil leaked all over it. The ride quality is personal preference. That's why I suggest finding someone who has the polys installed. It does make a difference going from rubber to poly. Anyone who denies that is simply not telling the truth.
 
RustyRatRod said:
If you have any question, find a friend who has the poly bushings everywhere in the front and see if they will let you drive it. It's not for everybody. Some like it, some don't. I know from a durability standpoint there's not really much difference between quality rubber versus poly. A good quality rubber bushing from Moog will last 40 plus years, especially as long as it does not get oil leaked all over it. The ride quality is personal preference. That's why I suggest finding someone who has the polys installed. It does make a difference going from rubber to poly. Anyone who denies that is simply not telling the truth.
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"Quality and rubber shouldn't be in the same sentence " OE rubber bushings never lasted anywhere near that long, let alone the junk moog has now. Many shops got pretty wealthy in the 60s/70s replacing front end parts on Mopars.
 
RustyRatRod said:
If you have any question, find a friend who has the poly bushings everywhere in the front and see if they will let you drive it. It's not for everybody. Some like it, some don't. I know from a durability standpoint there's not really much difference between quality rubber versus poly. A good quality rubber bushing from Moog will last 40 plus years, especially as long as it does not get oil leaked all over it. The ride quality is personal preference. That's why I suggest finding someone who has the polys installed. It does make a difference going from rubber to poly. Anyone who denies that is simply not telling the truth.
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Pretty good advice. Had Poly for years, going back to Rubber.
 
GMachineDartGT said:
"Quality and rubber shouldn't be in the same sentence " OE rubber bushings never lasted anywhere near that long, let alone the junk moog has now. Many shops got pretty wealthy in the 60s/70s replacing front end parts on Mopars.
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I started aligning cars when I was 10 in 1975 and that has not been my experience. As long as rubber bushings are a good name brand and don't get leaked on by the Exxon Valdez, they last a long time, from what I have seen.
 
RustyRatRod said:
I started aligning cars when I was 10 in 1975 and that has not been my experience. As long as rubber bushings are a good name brand and don't get leaked on by the Exxon Valdez, they last a long time, from what I have seen.
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Have to agree with this but we could replace lower ball joints right off the car carrier some years.
 
66fs said:
Have to agree with this but we could replace lower ball joints right off the car carrier some years.
Click to expand...

I worked for the local Chevy dealer from about 88-93. During that time, they had a recall on ball joints on the trucks. As you say, some were bad and already squeaking right off the pregnant truck.

As for the rubber argument, keep in mind too that being in a different location may have an effect on how long the rubber lasts, too. I am sure there are many variables there.
 
If there is anything that I can answer about PST Polygraphite products please let me know. I would be more than happy to discuss our product lines.

Thanks
James
 
had poly end links and bushings on front and rear sway bar, with the rear bar being the smallest I could get. rear a little to stiff, ended up switching rear end link bushings to rubber to relax the rear bar a little, the rear does not want to come around as much in a corner as it used to. So I think use which bushing works best for your application.
 
PST said:
If there is anything that I can answer about PST Polygraphite products please let me know. I would be more than happy to discuss our product lines.

Thanks
James
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I'm just waiting for your 1.03" torsion bars to be in stock. ;)

I already have a list of parts I'm planning on ordering from PST such as the strut rods and control arms, control arm rebuild kit, etc. As for the bushings, now I'm deciding between polygraphite or delrin.
 
Not voting but will comment based on my own experiences since I've used them all (poly polygraphite, nylon, rubber) both on street and autocross.
First, you're right to not equate corner carving to track or autocross with even moderately sticky tires. The tire temps, stick and surface makes a big difference.

JoesEdge said:
I'm about to pull the trigger on a front end rebuild kit and I can't decide if I want to go with Rubber or Poly bushings for the Lower Control Arm (LCA).

This is for a '74 Duster and my goal is to build a daily driven street machine that can handle well (hopefully very well).

I'm not planning on entering any AutoX's but some spirited driving up some mountain roads and freeway on ramps would be fun.
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Rubber in the lca and upper control arms will last longest if they are of any quality. I disagree with Pete on LCA being a continual failure item. Ball joints far more, and based on the TSB, probably many shops were replacing before needed because they checked wrong.
Polyurethane can permanently distort (deform) when the load and deflection gets too high. I did not have this happen, but did wear out after 50k miles, using the PST's original polygraphite LCA bushings. A more recent set, supusedly graphite impregnated (need to dig out reciept to see which seller brand) did not last as long. They deformed, however the autocross loads were higher due to other improvements including tires (Hoosier TDs and then Toyo RA1s).
During this time I switched from PST's UCA bushings to the Moog offset. I highly recommend this to get the more aggressive alignment. Occassionally a car won't need them to get the more aggressive alignment, but most will - especially earlier ones.
Nylon LCA bushings are currently installed. They transmit more high frequency vibration to the steering wheel even with tall street tires. How much you feel depends on the roads. Some highways here are smoother than others. However nylon is much tougher and while less elastic won't deform plasticly.
Here's my planned list of additional parts:

- Moog Lower Ball Joints, Moog Tie Rod Ends (11/16"), Moog Idler Arm
- PST or Reilly Motorsports Adjustable Strut Rods
- Hellwig Tubular Sway Bar
- Tubular Upper Control Arm (either PST, Reilly Motorsports, or Firm Feel - can't decide)
- PST 1.03" or Firm Feel 1.06" Torsion Bars
- Bilstein shocks all round (maybe up front first, then rears later as budget allows)

I have searched on this subject and there are quite a few old posts regarding this, but I'm still unclear.

Any reasons why I shouldn't go poly?
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Use the adjustble strut rods if you use off the shelf polyurethane strut rod bushings and don't want to measure and machine the bushings. Anything you can do to reduce for aft movement at the strut rod is a plus IMO. So poly here yes.

Front Sway bar - biggest improvement you can buy
Bigger t-bars - another excellent bang for the buck for your purposes.
Shocks - Good shocks are very worth it in autocross. Depending on your corner carving, maybe not as noticible, but my feeling is go all four even if it means not buying something else.
Poly sway bar end links and heavy spacer and washers are important and low cost. Poly sway bar bushings will squeak if not greased but worth the reduced deflection and breasable fittings are now available or can be home made.
A good, slightly more aggressive than stock alignment is a must.
Lower both ends of the car if you can and is relatively low cost. Remember the back of the car plays a pretty big role too.
Tires and road surface are the biggest determinent on how it all works.
 
Given delrin's lower impact resistance, I wouldn't use it for suspension on a street car unless I could verify the grade. 100T has great impact resistance, but I don't know anything about the rest of it's properties.
 
Mattax said:
Not voting but will comment based on my own experiences since I've used them all (poly polygraphite, nylon, rubber) both on street and autocross.
First, you're right to not equate corner carving to track or autocross with even moderately sticky tires. The tire temps, stick and surface makes a big difference.


Rubber in the lca and upper control arms will last longest if they are of any quality. I disagree with Pete on LCA being a continual failure item. Ball joints far more, and based on the TSB, probably many shops were replacing before needed because they checked wrong.
Polyurethane can permanently distort (deform) when the load and deflection gets too high. I did not have this happen, but did wear out after 50k miles, using the PST's original polygraphite LCA bushings. A more recent set, supusedly graphite impregnated (need to dig out reciept to see which seller brand) did not last as long. They deformed, however the autocross loads were higher due to other improvements including tires (Hoosier TDs and then Toyo RA1s).
During this time I switched from PST's UCA bushings to the Moog offset. I highly recommend this to get the more aggressive alignment. Occassionally a car won't need them to get the more aggressive alignment, but most will - especially earlier ones.
Nylon LCA bushings are currently installed. They transmit more high frequency vibration to the steering wheel even with tall street tires. How much you feel depends on the roads. Some highways here are smoother than others. However nylon is much tougher and while less elastic won't deform plasticly.

Use the adjustble strut rods if you use off the shelf polyurethane strut rod bushings and don't want to measure and machine the bushings. Anything you can do to reduce for aft movement at the strut rod is a plus IMO. So poly here yes.

Front Sway bar - biggest improvement you can buy
Bigger t-bars - another excellent bang for the buck for your purposes.
Shocks - Good shocks are very worth it in autocross. Depending on your corner carving, maybe not as noticible, but my feeling is go all four even if it means not buying something else.
Poly sway bar end links and heavy spacer and washers are important and low cost. Poly sway bar bushings will squeak if not greased but worth the reduced deflection and breasable fittings are now available or can be home made.
A good, slightly more aggressive than stock alignment is a must.
Lower both ends of the car if you can and is relatively low cost. Remember the back of the car plays a pretty big role too.
Tires and road surface are the biggest determinent on how it all works.
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^^^^^^^^^^^^^^^^^^^
this!
Thanks Mattax
 
I put the Hotchkis greasable LCA pins and poly bushings in my Duster and had a hard time noticing any difference in the ride quality except on terrible roads where the ride was already bad anyway. However not having the extra flexibility of the rubber bushing makes the strut rod length much more critical; I noticed after a few hundred miles the LCA slid back on the pins just enough to see a space and I will be installing adjustable strut rods ASAP as I have an odd clunk and sometimes my steering feels funky when making tight turns (also need to replace idler and maybe pitman arm). I think most of the folks here who had not-so-good experience with the poly bushings simply swapped them in place of the rubber and didn't change anything else; like 72BluNBlu said you really need to change out the bushings, pins, and strut rods all at once or you will have problems.

And for the record even with 1" T-bars and the poly bushings my Duster rides like a silk carpet on a still lake compared to your typical modern mid-size or smaller car which like to transfer every single little road imperfection to the chassis. I guess it's good for control and steering feel but I drive a lot of 2015-2016 model year rental cars for my job and they all ride like sh*t in comparison (I've driven Kias/Hyundais which are the WORST by far, Nissans, Toyotas, Fords etc.).
 
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