poly vs. rubber
This is a discussion on poly vs. rubber within the Suspension and Handling forums, part of the General Help category; which is better poly bushings or rubber. i always though poly were better till i read this article.... Myth-information .... ...
09-20-2011, 08:14 AM #1
poly vs. rubber
which is better poly bushings or rubber. i always though poly were better till i read this article.... Myth-information
.... so what do you all think. i want to know from people that actually use poly bushings, or anyone that has a opinion on this. im wanting to replace my bushings, was going to order poly, but now i want to make sure before i order them. this is going to be street driven, but i was trying to make it handle better.
09-22-2011, 06:46 PM #2
- Join Date
- Feb 2011
Not a fan of poly as a bushing material for controls arms. See below. Two examples of what can happen when the compliant rubber is replaced by hard plastic (high durometer - "low deflection") in a location that requires deflection, the metal flexed instead with predictable results. That article you posted is good information, and I have referred to it in the past. Poly works in static applications like transmission and motor mounts.
09-22-2011, 07:40 PM #3
Well that was an interesting read that I would say supplied a fair bit of misinformation itself. I can't say for sure poly bushings are superior but I can tell you my experience with them. I can tell you I swapped all my bushings on my Nova and my T/A and have never experienced "sudden oversteer" or binding. I have had tubular LCA's with poly bushings on my car for over 3 yrs. I had them off while I was swapping my diff and they had no deformation at all. I also never greased them in those three years and never had a single squeak. Also him using the sway bar bushings as an example of how poly deforms is ridiculous IMO any soft material that is constantly kept at a certain angle will eventually deform including rubber. An example would be that my rubber sway bar bushing were deformed, shockingly after a decade of use, so does that mean that its an inferior material? At the end of the day everyone will have an opinion on it and your gonna have to decide which material will work the best for you. I chose poly and I have no regrets. If you have any other questions post 'em up.
09-22-2011, 07:51 PM #4
Nope, I put poly bushings on my Yukon sway bars to stiffen up the roll.
They work just fine and make the Yukon a good bit more predictable in quick lane changes.Be who you are and say what you feel 'cause people who mind don't matter, and people who matter don't mind.'
09-22-2011, 08:22 PM #5
thanks for your information on this. i think im going to order the poly. i want a stiff suspension so it handles good in the corners.. all the aftermarket torque arms, control arms, and panhard bars, all come with poly bushings that i seen. so they i would assume they would be good or the aftermarket companies wouldnt use them, right?? if anyone else has something to say let me know please.
09-23-2011, 05:51 AM #6
- Join Date
- Feb 2011
Well, yes and Challenger launched successfully nine times, but that tenth time was a bitch for NASA wasn’t it?
That you can’t feel a failure mode in action doesn’t mean it isn’t occurring, a point alluded to by Thoikol engineers.
Poly is put forth as a solution to a particular problem, and then used in applications where rubber or a bearing joint would work much better. Poly has less deflection, which lessens the bound-rebound action of rubber. Works as a cheap fix to wheel hop in drag racing, which is what most of the aftermarket solutions for the F-body are targeted for. Drag racing is the largest portion of enthusiast market served by those vendors, BMR and UMI.
In areas like street driving, course racing, or autox where better articulation is desired why would less (poly) be better than more (rubber, bearing)? The answer is it isn’t.
Vendors will sell you poly because you’ll buy it. That doesn’t make it an upgrade. Depending on application, durometer of the bushing, state of the material around the bushing you may get away with it, but it isn’t optimal.
Global West Quote:
The vendor is telling you flat out, not might, maybe, or could, they are telling you flat out IT WILL BIND!
Polyurethane bushings used on both ends of the control arm. This type of a control arm is best used for drag racing. The bushings however, limit the rear end from articulating. Many drag cars can get away with this because of the way the car is set up. If this type of arm is used on the street or road race applications the rear suspension will be placed in bind when the car goes over bumps and around corners. This is because the control arm bushings will not allow the rear end to have proper movement.
It was a poor bushing end choice on our end. The poly bushing binds as the suspension tries to travel. Because of the bind the weakest point of the arm breaks, which is our threaded bushing end. We no longer off this style like this. So in reality the A-Arm itself didn't snap but the bushing end broke, still an issue and we have corrected it.
To fix it we replaced it with a Roto-Joint or rod end, both which allow the suspension to travel freely with little friction. We are sending the customer two Roto-Joints to replace the poly ends.
Sorry to see this happen. Thank you,
In reference to ES bushings in the caster location of the front lower control arm:
Watch that bushing at the back of the front lower arm..... It will fail, and probably sooner than later. The record is 4 days on my Camaro before the ring on the inside failed and extruded itself. It's a bad design, and the reason I do not run those bushings in that location. Just keep an eye on it---and honestly be ready to put a stock type bushing back in that particular spot because it will always give you trouble.
He refers to the short coming of polyurethane as a bushing material.
Chassis Engineering - Herb Adams, Pages 22 through 24
09-23-2011, 06:27 AM #7
09-24-2011, 06:42 PM #8
I agree its not the best bushing for ALL locations however where I have them they work very well and I have no issues with them. The rear lower a-arm bushing is a bad spot for it, I have UMI tubular a-arms so I admit I didn't think of that being an issue, they are in every other location though. IMO that doesn't mean its an inferior bushing material its just not meant for all locations. Like I said I have had no adverse reactions by switching to them and I've had them on for quite a while now with no failure.
10-18-2011, 05:13 AM #9
Finished changing out my front sway bar bushings with polyurethane stuff and larger bolt.
Really tightened up the body roll as the car has 100k on it.
Old ones were really worn.
Car handles really nice now, I'm happy.
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