How much of a difference do Polyurethane bushings make?

I cant handle poly in my personal cars since I drive them on the street a lot. The squeaking drives me up a wall. 

It depends on the car and how sensitive your butt cheeks are. It was a night and day change on my old 240sx, but I could hardly tell a difference on my s2000. 

ProDarwin said:

Poly can improve the way a car feels and drives.  But it degrades a lot faster, is susceptible to squeaking, etc.  

Can you elaborate a bit? I was under the impression that it would last longer, but there's no real logic behind it outside of the fact that it's "harder."

Simply add zerk fittings and use a silicon grease periodically and the squeaking is a thing of the past.  Easy Peasy.

bcp2011 said:

ProDarwin said:

Poly can improve the way a car feels and drives.  But it degrades a lot faster, is susceptible to squeaking, etc.  

Can you elaborate a bit? I was under the impression that it would last longer, but there's no real logic behind it outside of the fact that it's "harder."

Squeaking is often caused by the bushing rotating in the carrier as the suspension articulates.  Rubber bushings flex. Poly bushings generally don't flex as much and in many applications they essentially act like a bearing.  When they get dry, they squeak.

In reply to Ian F :

I should have been clearer - I was asking about the degredation point.  I know why they squeak.  :)

In reply to Ian F :

Agreed, but you missed the part about 400+ USD for rubber bushings from FM.  That is about 600 Cnd by the time they arrive here plus 13% tax.

Canadian dollars might not market as well as USD, but they are just as hard to earn.

Hopefully I will know the answer by the end of April.

Pete

Anyone try the polys with the spiral serrations? Supposedly helps the distribution of grease better.

In reply to NOHOME :

Ah... yeah - that's a lot of loonies for bushings. 

carguy123 said:

Simply add zerk fittings and use a silicon grease periodically and the squeaking is a thing of the past.  Easy Peasy.

As I said, that doesn't match my experience.  Squirt grease in the zerk and it only comes out one side, not the other one.  Other side still squeaks and binds.

It's the binding I care about more than the squeaking, because it effectively results in a random amount of extra spring rate right when the suspension starts compressing.  That makes for "interesting" handling...

I make my own out of delrin AF (the one with teflon in it) if I can verify that it only ever rotates.  I use poly for leaf springs though, and things like body or subframe mounts. 

All of mine have always been 2 part bushings with a small space in between them.  That is where the grease goes.  I've never had it squirt out of one end and not the other.

As far as spirals go, I've just done this on my 7, but haven't put it on the ground or greased it or anything yet.  It sounded like it might work better, but I have no experience with it yet.

I removed Delrin and went with the poly to give it some kind of give and take the edge off.

I only know them when they’re replacing completely thrashed and dried out rubber bushings. In the C4 they never squeaked while I had it. The c10 they do a little. I think. There are many other things that may be causing that so I’m not upset. Besides it’s so loud while running you can’t hear them!

as far as performance I couldn’t say. I’ve never driven a lowered c10 or new stock C4 to compare and both of these were so thrashed it had to be an improvement 

This thread is beyond odd. I have run urethane in nearly all of my cars (i plan on keeping) since '96. Only squeaks were from a honda I bought ussed with red bushings and no lube to speak of. All 7 other cars have had zero squeaks. Seriously. Maybe you guys are installing them wrong, using in incorrect (binding) locations or not prepping them? Some quick tips:

1. The only moving contact surface should be the sleeves. Most makes of urethane bushings halfass it, (looking at you prothane / energy ) and the shoulders rub and need to be radiused by an angle grinder. This is a purely (lack of) engineering issue. 

2. Use silicone paste. Not spray, not grease. No other lube will hold up. Pretty sure thats all the es stuff is. Liberally as possible on all mating surfaces, but particularly the sleeves

3. I have never added zerks, but tend to relube every 2-5 years, usually when doing other work. If going zerks, and it seems like a good idea, make sure your lube is correct, and adapter is clean. Any old petro grease is no bueno. 

4. Make sure they fit! Most suppliers are liberal with dimensions. A majority kits I have installed needed one or most inner urethane surface to be cleaned up so the binding was not excessive. This is what causes early tear-out most of the time imho. Some swear by texturing or grooving the inner urethane surface to hold grease, but I find proper clearance sufficient. I go for a light-medium drag with minimal sticktion (when installed!)

5. Handling changes can be somewhat unpredictable. Be prepared to return to rubber for 1 or 2 positions in MOST applications. Urethane is ideal for SINGLE axis movement. For applications that have large misalignment, multiple axies of movement, or perhaps are NVH transmission points, use rubber there. If unsure or unwilling to figure out what is what, go rubber. In old hondas this is the rear trailing arm bushing  and in some cases the front inner lower control arm locations, as they have a dynamic camber, and toe change. I imagine any multi-link is to be examined carefully. Strut cars may be fine, no experince there. 

6. Cool kids go OEM Black. The carbon content of the black urethane is rumored to cut down on squeaking. Is it magic? Graphite? Who knows. But it looks better than the red, unless goin full look-at-me show car. Could be all bs, but what is a rant without a random preference thrown into an otherwise objective point?!

7. NVH goes up, but overall comfort depends on application, and varies widely. I know some strut cars get really noisy after lcas are done in urethane, while sla cars seem to fare a bit better in general, from a small sample size. Lightweigt cars seem to both benefit more (handling) and suffer more (noise).

8. Derilin might be better (for racing/performance, not nvh) If you are SURE you want your travel fixed in one axis, derilin and friends are yours too. Because of this, I would make at least one bush at each wheel compliant so something can give before binding. 

9. Never tried the teflon tape thing, but also just learned about it. Seems like it would immediately become paste. Maybe fine PTFE solids in silicone paste is the magic product everyone is looking for. Will explore this as I am about to urehane bush a crv. 

10. Degrading has not happened to me. Period. I have over-stressed and torn a bush in a way unlikely for rubber, but not within operating conditions that can be sustained. I suspect this is an issue with using too litle lube, petro lubes, or improper fitment/application. I have had a few polyd cars go over a decade and 100k, but expect they are no better than rubber even when maintained. 

Sorry if most of this was covered, but I wanted to document my overwhemingly and apparently uncommonly positive experince with poly.

bcp2011 said:

ProDarwin said:

Poly can improve the way a car feels and drives.  But it degrades a lot faster, is susceptible to squeaking, etc.  

Can you elaborate a bit? I was under the impression that it would last longer, but there's no real logic behind it outside of the fact that it's "harder."

The poly in my Impala lasted about 35,000 miles before they completely fell apart and fell out of the sleeves.  The good news is that they finally quit squeaking when that happened.

In a rotation situation, poly doesn't stand up to abrasion or torsion very well.  In something like a motor mount, steering rack mount, or trans mount, they'll last forever.

^In a multi-axis situation I've had them fall apart in a few months.  I did the Saturn with them back in the STS days.  The swaybar-LCA bushing (swaybar is fwd link of LCA in that car) on the RH side lasted only a few events and minimal daily driving.

Agreed, in a somewhat fixed scenario they will last forever.  Unless you get oil on them.  I had a leaky cam cover gasket drip on the dogbone bushing of a motor mount (Saturn again lol), and disintegrate that bushing in a year or two.

I'm surprised no one mentioned Delrin or Del-Alum bushings.

Very little sticktion, nearly zero deflection, but a bit more NVH than poly or rubber

From comments I realized that I spiralled the wrong side.  I did the outside thinking that's the side that got the movement.  Well it probably will now.

More surface area; it'll probably last longer?