Poly bushings: Good or Bad?

**HillBillE** · 05-10-2011, 20:34

Well, Poly bushings seem to be all the rage, but are they really worth it?

Came across some interesting side effects while in Moab.

One of our club members bought an '01 XJ, it had a 2" BB and he put 31's on it. It did great wheeling.

But, the PO had installed a set of aftermarket LCA's (Lower Control Arms) as well as a set of red Poly Bushings.

Now these LCA's are nice, made out of solid box tube, great for sliding on rocks and not getting damaged.

Now for the downside. They don't flex at all, where stock Control Arms will give somewhat, due to thier design.

Now, no flex is good, right? Well, yes, and no. With no flex in the LCA, and not much in the Poly Bushing, something has to give during articulation.

Guess what that is? The axle mount for the LCA!

My take on this trail damage, is that the Poly Bushings are much stiffer than the factory rubber bushings. And with the LCA being solid, the 'flex' had to go somewhere during full articulation. It went right to the mount, and worked it until it ripped.

Now the really bad part, this happened on the "Big 3" in Moab, the 'Poison Spider/Golden Spike/Gold Bar Rim" trails. Right in the middle, about 3-4 hours off the trail-in either direction.

And with some obstacles that have no bypass!

So, what do you do? Be prepared!!

One of the guys had brought some welding rod, so we grabbed 3 batteries, 2 sets of jumper cables, and stacked 3 sets of sunglasses together!

(not the best set up, but hey, we got off the trail!!)

Did a little trail repair welding:

Of course, it's like 1400 hours and 80*! So we made some shade:

I had my 18V cordless grinder with for cleaning it up.

I'm waiting on the other guys to post pics, they have a couple of me wearing the stacked sunglasses as a 'welding shield'

My take away: Had the bushings been factory, this may not have happened.

Take away for everyone:

Anytime you upgrade one part of your rig, something else that it's attatched to becomes the weak link!

Doesn't matter what you upgrade, it will inevitably put stress on another part.

The trick is, being prepared for whatever happens!!

The next day, we were at M40 (Moab 4x4 Outpost) and Danny had a heavy duty bracket and skid plate welded on.

My welds weren't pretty, but they got Danny's rig off the trail, including the 'Golden Crack' and some other great obstacles!

**SavageSun4x4** · 05-10-2011, 21:01

UP on my soap box again: Poly bushings just SAY NO! and your pics says it all. There is a place for them of course. They work well with on the top of shocks and in all kinds of places where articulation is NOT a factor. Control Arms is not one of them. I use JKS CA with OEM bushings.

Problem with poly is it does not conform and depending upon what durometer you are using it transmits vibrations...ask anyone who has tried to use them for motor/transmission mounts. As for conformity while it does not, at some point it will if it does not snap off its mounts before hand. When it does conform after repeated extreme influences then its ruined and will rattle like a BB inside a box car.

Yea, I know the 'Pro's' use them and as soon as you go pro you ought to use them too.

TIP: You can tune your CA mounts that use OEM bushings. Jeep makes 3 different bushings, all the same size but NOT all the same durometer. Jeep Wranglers are the hardest, Liberty is next firmest and the GC use the softest. I prefer using the GC bushings. Softer gives more articulation at the extreme side.

**HillBillE** · 05-10-2011, 21:11

I had them in my CJ leafs, but after snapping 2 shackle bolts, I went back to rubber.

I do still have them for my 1" body lift on the CJ. A little squeaky, but fine for the BL.

**RescueJP** · 05-11-2011, 19:40

interesting

**gearhead1985** · 05-12-2011, 01:57

i don't have a problem with them and they last longer that rubber IMHO and i abuse mine i have more wear and tear issues with the rubber ones my only problem is i can't keep any bushing intact on my anti wrap bar i get about 3 months of dd use before it starts popping and banging under acceleration the only place i use rubber is on my drive train mounts engine, trans and transfer case then i use brown dogs ultra flex rubber bushings

i makes since that on a stock xj tj with after market short arms there is alot of force that will be applied and nothing will twist like a stock arm so something will break and i have seen stock lca mounts shear off by just looking at a rock but don't all or most after market long arm and short arm manufactures send poly bushings with there kits

@HillBillE what grade bolts did you use on your shackels when they broke i run grade 5 torqued to 40ft-lbs

**HillBillE** · 05-12-2011, 09:31

Originally Posted by gearhead1985

..................... and nothing will twist like a stock arm so something will break and i have seen stock lca mounts shear off by just looking at a rock but don't all or most after market long arm and short arm manufactures send poly bushings with there kits

@HillBillE what grade bolts did you use on your shackels when they broke i run grade 5 torqued to 40ft-lbs

I run Grade 8 bolts. I also welded a bracket between the shackles, making them stiffer. I broke bolts less often after switching back to rubber bushings, I haven't broken one yet since making the shackles '1 piece', they look like the letter "H" now.

You're right, a lot of companies do ship poly bushings. I have a set of IROR long arms (first generation) and they have rubber joints up front, and rebuildable ones at the body 'frame' rail.

It's a steel ball with poly bushings and is greasable. I believe they're called 'Johhny Joints?
So far, they have worked great, with plenty of movement and no binding.

Like these:

http://www.google.com/search?tbm=isc...g-sx1&aql=&oq=

**irish1371** · 05-14-2011, 01:19

use to use poly in my springs on my 71 jav at the strip. that lasted about 3 weekend. they may have been a hair more consistent on times down the strip but dam, couldn't go anywhere on road with them the squeeked like a nun in a whore house. drove me nutzs

**SavageSun4x4** · 05-14-2011, 19:15

Poly: I say this alot and will say it again here. There is a time and a place for everything and this applies to poly just as much as to rubber.

Where poly works for you in in situations where the poly is not impacted by angularity. Best example is the Control Arms. IF the CA only moved vertically things would be fine, but they don't. Instead as they move vertically in the suspension arc, they also move horizontally (due to the arc of the track bar). This is where the poly's lack of 'crush' ability causes CA's to be ripped off frame/axle.

Now before someone says yea, been running poly on my TJ CA and never ripped off a mount. Well yes, it can and does happen. If the Poly is of soft enough durometer is can crush, but Poly by nature does not rebound like rubber. So what will happen is the Poly will sooner or later remain in the crushed state. Poly does not have the good rebound qualities that rubber does.

Where does Poly work best? In most places where the contact surface of the Poly REMAINS in contact with the contact surface of the bushings opposite surface. In example: Use in body mounts* on a TJ, the movable shaft end of a shock absorber, spring spacer/levelers and bump stops are all good uses.

* All too often I have seen owners install a body mount kit and end up with cracking in the door corners of the tub and or note tub vibration. Often and this has caused body lifts to get a bad rap, unfounded! In every case where I have been able to exam the install what I have discovered is they did not use the OEM bushing along with the BL kit. Poly is to hard a component to use in BL by itself, you must retain the OEM rubber bushing to absorb the vibrations and to provide the cushioning needed to support the body.

Take Away: For the DD/weekend wheeler there is a time and a place for Poly and rubber both. Generally speaking high angularity contact and or complex movement tends to work best with rubber based components whereas Poly works best in surface-to-surface full contact applications.

**stoneygibson** · 05-17-2011, 10:34

That is a BAD Ass story! I love it! Hats off to you and your crew for being so prepared and creative!

Hell yeah

truly jealous

**HillBillE** · 05-17-2011, 20:45

Originally Posted by stoneygibson

That is a BAD Ass story! I love it! Hats off to you and your crew for being so prepared and creative!

Hell yeah

truly jealous

@stoneygibson : Thanks!

My local club is a 'streetable' club, we drive everywhere we wheel, including the 3K mile round trip to Moab every year. We need to be prepared!

We have a great crew, and everyone adds something to the mix.

When I hit the road for a wheeling trip, I have damn near another Jeep in spare parts!

We've rebuilt a manual trans, done pinion bearings, rebuilt driveshafts, changed front and rear axles, as well as doing some trail welding!

Not only do we like to be prepared, we just can't afford to have a shop fix stuff!