Rubber Vs. Poly suspension stuff?

[71charger_fan]

"Rubber bushings are essential, and designed, to provide necessary elasticity in an infinite number of axis's. This is due to the requirements of the suspension to not only move/twist through a large range of motion"

I'm sorry but I have to say I don't buy this. Rubber is not essential; some sort of material capable of absorbing vibration and maintaining the suspension components very close to their engineered axes through their range of motion is essential. You seem to have argued against yourself saying race and rally teams use poly for better handling yet, through some miracle of vehicle physics, poly makes a street car handle worse? Granted, poly will transmit more vibration into the unibody. I don't find it to be harsh. Will it wear out early compared to rubber? Perhaps. But, with the limited mileage I put on mine I believe the rubber would rot long before poly would wear out.

Wouldn't optimum handling come from mounting the upper and lower control arms in lubricated bronze bushings? That way everything would remain in its designed geometry. Except, of course, it would beat you to death. Poly minimizes front end geometry changes through the range of suspension travel because it does not flex as much as rubber. Am I wrong in thinking your argument is saying that having your control arms squirming around is a good thing. I don't believe you want your suspension moving through an infinite number of axes. Ideally, you want each control arm to pivot on one axis.

Poly provides some give, rubber provides a little more. Is one better than the other? Yes. I suppose each is better than the other depending on what you want. I'll stick with the poly for the tighter handling but I can understand why many people choose rubber for less vibration and a smoother ride. The only poly bushing I ever installed that gave me a noticeable increase in vibration was the transmission mount bushing. That one I wish I'd left rubber.

[Brock Samson]

BTW: Terrible One tells me the S.S. springs are supposed to crank the car to one side,.. Is that right?.. they don't on mine..

I'm enjoying the debate and wondering if maybe i shouldn't go back to all blubber.. err,.. rubber with the heavy duties since i spend far more time on the Road then the Track,.. where i'd like more "comfort" is when bombing down HWY 1 to Santa Cruz and back at off peak hours...
Do you have any idea just how much how fun that is!?..   

[BLAM]

Love your R/T!

I wouldn't call it a debate, these are just opinions based on pesonal preferences.  Poly gives you a tight suspension at the cost of a smooth ride.  Rubber gives you smooth ride at the cost of a soft suspension.  That is not to say poly results in an unbearable ride or that rubber results in car all over the road!  Not at all, it is just a choice of personal preference.

As I stated before I prefer a middle of the road solution which is a combination of rubber and poly.  I put poly on the rear springs / shackles and all sway bars.  Moog goes on all else in the system.  I like poly on the rear end because the loads are applied from the axel through the springs which is a large moment arm resulting in huge loads which will deform the rubber bushings in at least two axis.  I like the rear to track true!  Poly goes on the front sway bar because I want the effects of the sway bar to be imparted on the LCA immediately upon entering a turn.  Not after all the rubber bushings compress first.  In the front the bushings on the LCA and struts are essentially in a single axis so rubber is OK in my opinion and do a lot to smooth the ride!  Upper control arm bushings are lightly loaded really doesn't matter what you put there, but rubber is a little cheaper.

I think HD springs are the way to go if you can sell you S.S. to a racer.  i would keep the poly bushings in the rear though.

Yes I do know what you mean about the PCH!!!!  Fun! Fun! Fun!

[deputycrawford]

I don't know if my two cents will mean anything here but I run the .960 torsions, KYB shocks all around and the XD R/T springs in the rear. I run all rubber bushings and love the stiffness of the car and the ride quality. It soaks up the big bumps without rattling my teeth and pulls 1.84 60 ft times at the drag track. I have a 9 1/2 inch converter and a 4.10 gear in the 8 3/4. I truly believe I have the best of both worlds. Don't think twice about running the XD rear springs. They will surprise you.

[RT DAVE]

I run poly bushings in mine and don't notice the ride being rough.  I'm comparing this to my Intrepid, however, and not the charger with rubber bushings since I don't remember what that was like. 

[is_it_EVER_done?]

Stratocharger:  As you are discovering, they are called "SUPER STOCK" springs for a reason. They are one of the best upgrades and bargains ever created for drag racing/straight line acceleration situations, but they are terrible for any type of handling other than drag racing! You will find them to be very stable under full acceleration/rear weight transfer, but "scary" squirrelly in an "un-loaded", or front end loaded (braking) situation. The shocks will have a great deal of effect on minimizing/magnifying this, that's why good rear drag shocks will have so many adjustment possibilities.

Just for the record, keep in mind that in your original post you stated "you like stiff". That is not intended as a "jab" at all, just a general 'be careful what you ask for" type of observation.

71charger_fan:  To save space, and avoid extensive cutting and pasting from your last post, and my previous ones, please re-read my posts, and you will find that all but one of your questions were already answered, without any contradiction or argument against myself at all.

As for your question about whether optimum handling would be provided from solid bushings, Inferring that this was meant with stock suspension, the best way I can explain this is to request that you go look at the suspension on your car. If you look down on the engine compartment side of your cars suspension, you will see that the torsion bar runs at a straight, 90 degree X – Y axis, but that the upper control arm angle is at a radically different axis at both X and Y than the pivot points of the lower control arm/torsion bar.

If you look at it from a side view you will see that they are different in that X – Y axis also. Notice also that the upper control arm rides on two separate pivot points that have about one inch of adjustable differential from one another (for alignment purposes) which requires even their single axis to become "multi dimensional". Plus the fact that the strut rod causes every component (except the torsion bar) to move in a semi circular motion in addition to their (off axis) up and down motion, and it becomes apparent that if the bushings were steel (or some other solid material, the suspension could not move at all.

This unequal motion of the suspension is meticulously engineered in. Poly tries to minimize the (essential) "infinite axis" motion of the suspension, and poorly mimics the results of increased torsion/sway bar diameters, and increased shock performance. All this while causing undue stress on the suspension mounting points/components, and bushings themselves, while providing no gradual loading of the major suspension components. 

If the reduced flexibility properties of Poly had any benefit, tires would be made out of it instead of rubber, but the infinite flexibility of rubber is as essential for performance in tires as it is in suspensions. Just watch a wrinkle wall slick flex if you have any doubts.

As good as the stock Mopar suspension is, it does suffer from required – designed in – limitations. This is due primarily to the fact that it had to be a compromise between low effort manual steering (standard on most cars/models), and self-centering directional stability that could only be maximized with power steering. Fortunately Chrysler and Moog (Moog being the OEM supplier to Chrysler) designed the offset upper control arm bushings that are capable of solving a myriad of problems. The best of which is being able to offer a huge increase in positive caster (stability).

Poly can't offer this even if it's manufacturer wanted to, since the material is incapable of torsional flexibility, so it is stuck with the original designed in compromises unless you undertake a mechanical realignment of the stock suspension geometry.

If you prefer Polly, fine. However your (proper) upgrade of other suspension components, in my opinion, negates any attributable stated Poly benefits, but if you have A-B type comparisons, or other experience as to why/how Poly is better, I am more than willing to listen, as I learn something new about these cars every day.

One thing I would like you to consider, is that the "which is better, Poly or rubber" question is frequently asked across the internet. It wouldn't't be if the person asking the question had experience with each (regardless of which is actually "better"). It is my opinion that it would be a disservice to recommend Poly, as it is a product that can only be applied successfully through experimentation and other modifications, and can be potentially dangerous (as Stratocharger is finding out) when applied in the wrong situation. Would you not agree that suggesting rubber is not the safest, most probably pleasing result suggestion to those that ask? Even if (as I and you state) there are applications that Poly might be of benefit. - Overall, you can't go wrong with rubber.

[71charger_fan]

"requires even their single axis to become "multi dimensional". "

I'm sorry, but I'll have to respectfully disagree with you on this, and other, points. Personally, I believe you have some misunderstandings on the function of the front suspension and you believe I do. I don't for a second believe the control arms are meant to move through infinite axes but are allowed to simply because there has to be some trade off between maximum handling and maximum comfort. Rubber and poly both provide this trade off at slightly different degrees. Poly limits the movements of the suspension components more than rubber which I believe is a good thing and you seem to believe is a bad thing. Rubber absorbs more vibration but, to me and many others, at the cost of degraded handling. So enjoy your rubber and I'll enjoy the poly. If it wears out sooner than rubber, fine, but, at only 1200 to 1400 miles per year that's going to take a while and I'll probably take  the whole thing apart again to paint it before it wears out and put new parts in then just as maintenance.

So you have a pleasant weekend and, if the weather is nice, enjoy your car. I plan to get mine out.

[Brock Samson]

 Hey Gents thanks for the advice:

We've had 25 days of rain out of the last 31, and I've been pretty busy so i've only got three days of driving/testing in.

the latest adjustment was lowering the tire pressures 5 Lbs.. and that had the obvious effect of lessening the squrrerly darting about and squeaking at any minor kind of steering inputs...

My Alt. went out, which it took me three days to correct cause these days i don't have the time anymore to mess around in the garage and at the shops...
but anyway...

I went out to Candlestick Parks' parking lot to conduct some launching and burnout testing and for fun...  I squared off besides my own burnout patches to measure the leangth of the rubber and made some objective comparisons throttle breaking, shifting at various RPMs etc. im gonna need a new right rear tire... From a dead stop the charger is an absolute hoot! i know i need a posi rear and lower gears, and torque boxes would help keep my glove box from flying open.. and now the R/T is a one trick pony unbeatable on the city streets...

...but all my Freeway excursions were scary waaaaay beyond what i'd deem an acceptable risk,.. 

I dont remember these wicked directional changes before... really a cause for concern...

so anyway it's been raining for three days now, and I'd still like to hear of anyones' experiance with different chassis setups..

right now i'm thinking i'd gladly sacrifice some stoplight to stoplight attitude stability.. to gain some freeway prowess...

Sorry if my terminoligy is incorrect...

I'm thinking now of swapping the S.S. springs for the H.D.s as suggested, and would like to hear other suggestions and ideas..
I'm wondering if i could get the lower stance of some of my favorite chargers on this site... cause mine's alittle high on it's haunches as it sits..

see below..


This is Charger1970s ride and a stance i used to have and prefer prior to my BB 440 and S.S. springs...



It seems to me just having the car lower, the tires more up in the wheewells and the center of gravity an inch or two lower would help the handleing and freeway stability.

your thoughts are most appreciated...
       

[AKcharger]

I used poly's on my wife's '72, really didn't notice a diffrence in ride and YES they do squeek and I lubed them. Installation was easy because they were stiff but I'd go back to rubber to get rid of squeeking, to me polys are not worth all the hype they get

AK

[Brock Samson]

i need to mention rereading this thread that the freeway stability improved a tremendous amout with new tires that i bought,..
no more squealing darting or tramlining... i guess it was an obvious fix... burnouts and normal wear will degrade a cars ride...

[Ghoste]

But burnouts are so worth it in the short term aren't they? 

[Mike DC]

 
Chargers do handle better when the front end is lowered. 
Lower center of gravity of course, but the lowered roll-center and increased negative camber probably does a lot of it too.

But these cars don't have a lot of wheel-travel left between ride height and bottoming out once the front end gets cranked down.

 

[Bandit4142]

First and foremost, I want to say that I appreciate the information and personal opinions in this thread.   I will be replacing all the bushings in my '69 within the next month, and that leads me to my question.   For me, my Charger is a "Daily-Driver" that my wife and I take to shows on the weekends.  I live in rural Colorado, so what this means is I drive 200+ miles round trip for a show.   I would also like to hear combinations for the ultimate "smooth" highway ride.   Track worthy handling isn't my goal, and hasn't been since I started this project, long distance traveling is.   Does anyone have a combination for a true highway cruiser?   

[RTPTRON]

First and foremost, I want to say that I appreciate the information and personal opinions in this thread.   I will be replacing all the bushings in my '69 within the next month, and that leads me to my question.   For me, my Charger is a "Daily-Driver" that my wife and I take to shows on the weekends.  I live in rural Colorado, so what this means is I drive 200+ miles round trip for a show.   I would also like to hear combinations for the ultimate "smooth" highway ride.   Track worthy handling isn't my goal, and hasn't been since I started this project, long distance traveling is.   Does anyone have a combination for a true highway cruiser?   

My 68 drives and handles pretty well for the primary suspension components to be 1968 technology.  I rebuilt the front end with rubber bushings except for the sway bars which are poly.  I installed Edlebrock IAS shocks and and rear end snubbed.  Installed new alloy wheels and TA redials.  It don't handle like a sports car but I can go around curves pretty well and I don't get a nose dive when I brake hard.

[8WHEELER]

Nice picture Ron I wonder who took it    Here, I made the color more correct.

Dan

[Ranger Max]

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[RTPTRON]

Nice picture Ron I wonder who took it    Here, I made the color more correct.

Dan

8WHEELER took it!!!  Thanks DAN
Ron