Good or Bad Idea: Polyurethane Suspension Bushings

I have all poly bushings on my 99 F250 Super Duty and I like the feel. The guy who had it before me put them in and even now with at least 100K miles on them they are still tight and good.

As far as ride quality goes the stiffness of the springs and shocks plus the type of tires you have will affect the ride far more than the bushings do unless they are pounded to pieces.

GA, The only thing I would add to your comment is that if you go with a larger front sway bar you should also add a stiffer rear sway bar.

The Suburban has a significant under-steer from the factory and increasing front roll couple without increasing rear roll couple can make that worse.

Sore Mr. 1,000,000 post. All that fame seems to have gone to your head, posting long wordy posts to make yourself feel good. It should have been mine.

Thanks Tom !!

Congrats on the Millionth honor.

I agree with the other 2. Besides, with this mileage and hard service, the old ones are probably pretty well shot. I'm not sure what OEM is now, but probably not polyurethane.

Well the poly bushings are certainly stiffer and do transfer noise, so like anything it's a tradeoff....but as I see it, your main complaint is the instability of the steering, and that has to do with front end alignment geometry....

Here is an explanation of terms, their meaning and effect each has....

http://www.ozebiz.com.au/racetech/theory/align.html

I used to own a BMW 635. to say I loved the car is an understatement. I lowered it, had 3 grand in wheels and tires, extrude honed the intake and exhaust manifolds, etc. although these cars had exceptional handling they were known to have a shimmy around 40-50MPH because of worn rubber bushings. I elected to go with the red urethane that was never going to wear out. the swap certainly tightened things up and the wiggle went away. the downside was more noise being transmitted through the steering wheel.

if I had to do it again I would have stuck with stock and accepted that for a quality ride I would have to replace the rubber every now and again

I also wonder about the noise, hence my reason to query the peanut gallery. The Suburbans, like most full frame trucks have rubber isolators between the coach and the frame which isolates much of the road noise. I'm guessing with the pittman arm steering and all the linkages between the tie rod ends and the steering wheel, I probably won't get as much noise as you would with a Beemer which I am sure has a much more direct connection between the rack and the steering wheel. Thanks for your input !!

Cheers !

"Outside of motorsports where comfort takes a back seat to performance,"

I think comfort sits in the grandstands. There is no back seat in race cars.

Honestly, why bother doing this to an SUV? It's not a sports car.

I would put in OEM components and if you ever need or want to sell the vehicle you won't limit the potential market of buyers.

Part of the reason I am even considering them is because the OEM bushings are rather expensive, even ordering them through discount web sites. A set of aftermarket polyurethane bushings are about half the price of the OEM's. I'm not really looking for better suspension performance because the OEM ride when new was quite good (other than the vague steering issues with this series of GM trucks).

After 200K+ miles all my parts are pretty much shot so I'm going to it all at one time rather than piecemeal repairs.

We use Poly bushings in Panama, Central America all the time because the roads here take a toll on the rubber ones.

They do tend to be a bit firmer but that is exactly why most people buy them. As said above, shocks and tires will have a much grater impact on comfort and handling than the bushings.

Only drawback is ocasional squeeking. Make sure you use the grease suggested by the manufacturer when pressing in the bushings.

Most of the people I know use Energy Suspension brand bushings.

The poly bushings are becoming more common than most realize. Some of the standard replacement bushings from NAPA are poly. You have a truck chassis. The difference in noise from the anti-sway bar bushings should be un-noticeable. The only difference would be the amount of noise transmitted through the two different materials. It is not like there is a slapping steel against steel.

There are some frame to bar bushings that are available with a grease fitting on the "U" bracket that locates them. If available, they are worth it for long life.

As for your 1/2 ton Suburban, please allow me to share this with you. We had a 1/2 Suburban that we used as command vehicle at the airport. The original complaint was that the door handles were trying to scrape the ground on turns. It had a puny front bar that had lost all four of the bolts holding the "U" brackets to the frame. Some searching allowed me to retro fit the bars from a 1 ton duel wheel crew cab truck. The front bar was just the bar, the "U" brackets and correct sized bushings for the bar. The back required the leaf spring lower plates from a 3/4 ton Suburban to provide the mounts for the rear bar. Then used the factory 1 ton bar, along with the matching "U" brackets. The 1 ton lower plates were the wrong diameter for the smaller axle. The rear links were shorter than the 1 ton because of the shorter leaf spring hight. The rear shocks mount to this plate for reference.

It was no sports car. But it was MUCH more drivable when pushed hard. Predictable, and secure in turns. Well worth the effort. After the truck was retired, I removed the bars, and still have them. Rear is easy to ID because of the unique shape, and it appears to be 1&1/16". The front that I think was used on it looks to be 1&1/8". Our 'berb was a 91. Do you want the bars?

One more thing on abusing trucks like that. We did the big bar conversion to an 85 F350 fire truck that also was "pushed" hard. Addco was called for advice. They recommended a 1&5/16" front and a 1&1/16" rear. Because the truck was diesel, with a wider radiator, and related wider anti sway bar frame mounts, they could not bend a bar that thick to fit the truck. The answer was 2 front bars, and one rear. The original 1&1/16" front on stock location, and another bar fitted to the back 1/3 of the strut bars from the Twin I Beam suspension. And the rear one supplied by Addco. All bushings were poly on this, and it cornered so hard, it would throw the hose and nozzles off of the cross-lays. We had to wedge them to keep them on board. At one time we decided to try a more aggressive tread pattern to get better bite in the sandy areas. That was a big mistake. We were using all Goodyear tires on everything. The G159 tires did everything well except traction on the sandy areas. So we went to a G133 which had a dog bone tread compared to the smoother rib design of the 159s. It was like driving on tires with low air. It squirmed all over the place. One week and they had to go. SO, take a look at the tread pattern on your tires. The more aggressive the tread pattern, the less stability on turns. If you need to, buy a pair of used tires with a calmer tread pattern, and see if that helps the directional stability. Anything I can help with just let me know.

Hi Bob,

Thanks for the detailed response. I appreciate your efforts. I think I am OK with the roll stiffness of this particular chassis. It does track well in the turns and I don't seem to get a lot of chassis roll. I agree with you that the additional noise transmission to the fame may not be all that noticeable because the coach is isolated from the frame with rubber isolators. I run the Michelin LTX tires on this truck but these tires pretty much have an automobile tread so they run nice and quiet. Definitely not for muddin'. They do pretty well in the sand once you air them down because the tame tread doesn't dig down.

I appreciate your inputs on the bars. I will give that some thought.

Thanks !!

BSR

As others have said, performance will probably improve at the expense of noise transference.

c 1990, I replaced all the completely shot rubber suspension bushes in my Triumph Dolomite Sprint (70's British "supercar") . Performance was naturally improved, although I couldn't compare them against good rubber bushes. However, differential noise increased markedly - enter teflon oil additive and additional boot (trunk) insulation.

Cheers

If you really want to get crazy, there is a rear bar used on GM step vans that is 1&5/8". With some searching, it should be able to be bolted up. And I have always wanted to stack two bars one on top of the other.

Bars are fine, but balance is the ticket to a good handling vehicle.

As far as steering goes.... I think you should check the caster. It is a common problem...more common than you would think.

GA. Even tires (type, height and width) and pressure in it are important.

Modifications outside the slope of the manufacturer get a red card at the obligatory automobile inspection centers in Europe.

Caster is the one characteristic that is not adjustable on this suspension. (Other than raising or lowering the rear end.) Once I do all the replacements, I have it put back up on rack for a full alignment.

Cheers !

Re: Good or Bad Idea: Polyurethane Suspension Bushings

I agree it's a no brainer. The urethane bushings tighten up the suspension immensely. And it might make a little bit of extra noise, but not enough to outweigh the safety advantages of better handling. I currently have a 1998 E150 ford van that had been crashed before I purchased it. After driving it for about a week I had serious reservation as to it's safe driving capabilities. As it turns out the previous owner decided he did not want to spend the money to replace the sway bar and pocketed the insurance money. I replaced the front sway bar with one off of a E-250 van and that helped greatly. as the truck had over 100,000 miles on it the springs were about worthless. I replaced them with an additional 1000 lbs stronger units and added a Helwig 1-1/8 rear sway bar and what a difference it made, it stopped all of the sway and the truck became a lot easier to drive safely at highway speeds when towing our safe trailer. Sometimes we were towing 5-6000 lb safes and often more but very little issues with it to date. All of the new parts, sway bars, and springs had urethane bushings in them as the local spring shop recommended them over rubber for longevity and safety for the extra weight. And the highly recommended that we lube them with a Teflon grease before we installed them. I can tell you that my highly tuned ears (AKA 56 year old mostly deaf according to wife / selective hearing) does not notice any additional noise level. Just my 2 cents. Duke P.S. getting tired of having to cut and paste posts because of time out guess I am just getting cranky in my old age.

If you write it in notepad, you can paste it. Its not easy though. I don't want to go into how to do it...(its an adventure in itself), but you can paste in the edit box.

Thanks for the input. I have the same selective hearing complaint from my missus as well. I'm all of 51 at the moment, but completely deaf in my left ear due to a benign brain tumor, so I have a bit of an excuse.

I've been OK with the truck's suspension overall. We tow a 32 ft travel trailer, but we installed the Hensley hitch when we bought the trailer. Best $2500 I have ever spent.

Things are pretty loosey-goosey on the front end primarily due to wear. New OEM stuff would tighten things up pretty well, but the aftermarket poly bushings are significantly cheaper.

Cheers !!

BSR

Are you planning to replace the upper and lower control arm bushings? The Polys for the arms are also available, but from what I think I am hearing from you, reduced movement from them may lead to a harsher ride on less than interstate smooth roads. On that note, replacement control arms are falling in price while ball joints seem to keep raising. If you have to pay to have the ball joints pressed in, the complete arms may offer some savings as the arms have new bushings and ball joints in them already. They also shorten turn around time. If you need a price on something, send a PM. Bob.

Most of our driving tends to be interstates. The roads here in Maryland are generally in pretty good shape as opposed to pot-hole hell that I lived through in New England. When I worked in Boston back in the early eighties, there were some pot holes you could just about swim in.

I was think of replacing the upper and lower control arm bushings as well. I bought the super heavy duty ball joint press tool from OTC to replace the ball joints. I am considering the replacement control arms and those come with new bushings already installed but I haven't decided one way or the other at this point.

For the GM OEM parts, I have been buying on-line through Flow GM. They seem to have the best prices and they are easily half the price of the local GM dealer even with shipping.

http://www.gmpartsdirect.com/

Cheers !!

BSR

Thanks for the link. New to me. How does this compare?

	Control Arm - Upper - Front Susp	Control Arm - Upper - Front Susp	Control Arm - Lower - Front Susp	Control Arm - Lower - Front Susp
	3 Images << Prev Next >> Angled	3 Images << Prev Next >> Side	3 Images << Prev Next >> Side	3 Images << Prev Next >> Side
	Qty	Qty	Qty	Qty
Part Number	NCP 2605308	NCP 2605308M	NCP 2605369	NCP 2605370
Product Line	NAPA Chassis Parts	NAPA Chassis Parts	NAPA Chassis Parts	NAPA Chassis Parts
List	212.26	159.18	383.34	383.34
Cost	100.99	75.69	182.39	182.39
Unit	Each	Each	Each	Each

I'll have to check that out. Do you know who produces the NAPA parts?

A lot of their stuff is reboxed name brands. My guess is Moog or TRW.

CAN YOU HEAR ME NOW?

I have done this on two trucks and I have no regrets.

The improvements in steering and response is well worth the expense.

If I ever wear out the truck I have now, my next truck will get the same modifications.

Thanks !! I figured others with trucks have probably done this and I thankful for the insight. I just didn't want to go through all the work, and then find out that the noise or harshness made the truck unpleasant to drive. You and others have not found this to be the case with trucks (as opposed to unibody autos which are completely different animals). Given the inputs I have thus far, my inclination is to try the poly bushings (but lube them as several have already mentioned.)

Cheers !!

BSR

Greetings Robin

Having been involved in SCCA class racing I can tell you from experience that poly bushing are the way to go for on track handling performance.

In a daily driver the poly bushings will make your dentist very happy as they rattle all your fillings loose. Especially if you have to deal with winter roads and those wonderful temperature and ice caused speed bumps that arise from the effects of cold and ice on concrete roadways. You will replace shocks, struts, and upper strut mounts, more often too. It is also a good idea to replace the front springs when making this change as these bushing will give your stock springs a good chance to collapse in a few years time.

I use them on my 1987 Shelby CSX (#719) for all suspension mounts. It totally changed the way the car handles for the better.

I do NOT use them on my 1967 Shelby GT350 (#2209) As the suspension components (double wishbone fronts) were not designed for them and replacing the Shelby suspension parts is not an option so damaging them by using the poly bushing is a no way no brainier. Plus Poly wouldbe of limited effectiveness due to the inherent weakness of the Mustang front suspension and chasis structure. Even the changes Shelby made could only do so much to strengthen what was a poor design to begin with.

If you go with them you will never have to replace them under normal useage, thats how hard they really are. You will eliminate a ton of slop from your suspension and you will be able to tell if that ant you just ran over was over weight.

Good Luck!

Hi Rashavarek,

One thing I am counting on is the isolators between the coach and the frame. I don't think I would use them on any daily driver that has a unibody construction. I notice a significant difference between driving my 05 V-dub Jetta and my Suburban or F-150. The full frame trucks definitely transmit far less road noise into the cabin. Others seem to be happy with the poly bushings in their trucks. I think I will give it a try. Time will tell whether I made the right decision (for me) or not.

Cheers !!

BSR

My half-ton Ford van didn't even come with an anti-roll bar so I went to the wrecking yard and had them take one from a three-quarter ton. Somehow I ended up with red poly bushings.The handing felt too loose without an anti-roll bar. I also put Loadleveler springs in the front but that might have made the ride a little too firm. But I put KYB shocks on all four corners and that made the ride a lot nicer. That was over twenty years ago and the shocks are still working good. (Want a good deal on a set of slightly used OEM shocks?)

When I replaced my rusting out Falcon station wagon with another like it in good condition I though about doubling up the anti-roll bars since I had the spare parts. Never did it though. Wonder how it would have worked.

One time on an older van I put Monroe heavy duty shocks on it. Made it ride like a buckboard. Then a mechanic suggested Gabriel light duty gas shocks. What a difference!

Speaking of shocks, in the last year or so, I replaced the worn out OEM dampers with the mid-grade single tube Bilstein shocks. What a disappointment. The low speed rebound damping is way too soft. As soon as I put them on, the wallow and side-bob was noticeably worse than the worn-out OEM units. Additionally, the compression damping is way too hard. I double-checked the Bilstein catalog and I ordered the ones they recommended for the truck. I plan of writing them and asking them what's up with that?

Twenty years ago, I put Koni adjustable dampers on my Mark II Jetta. That was a good decision. I loved those dampers. They worked nice, controlled the ride well and didn't make the suspension noticeably harsher than the OEM units.

Cheers !!

BSR

I put a set of Edelbrock shocks on the replacement for the burb, a 2000 G series van with a high top addition. The shocks were never up to my expectations. Too soft when thrown into a turn. Last year I pulled them off and replaced them with Monroe Gas- matics. I liked them much better.

I will consider the Monroe's. They also tend to be a lot cheaper than the 'premium' brands. I honestly expected a lot more from the Bilsteins. Thanks for the tip !!

I miss the old Monroe Super 500 shocks. Strong like Jonny Walker.

I replaced my OEM bushings with poly bushings on my 4x4 because I beat the truck pretty bad. If you are just looking at rebuilding your front end then I would stick with quality OEM bushings made by someone like MOOG. If you are just replacing all of the steering components and ball joints and weren't planning on pulling off the control arms to replace the bushings then just stay with OEM. I wouldn't do the front and neglect the bushings in the back. You have 206,000 miles on the OEM bushings, I would say they held up pretty good.

The back is going to get a going over as well but I figure I will do one end at a time. When you put in the poly bushings on your 4X4, did you notice any change in the road noise, suspension harshness, or noticeable changes in the feel of the steering?

Thanks !!

BSR

The road noise was fine. The suspension got tighter. I also put a nitrogen filled shock on the truck as well. I bought my bushing set and shocks on line from www.suspensionconnection.com and I bought my suspension parts on line at www.rockauto.com. Rockauto was half the price of autozone on the Moog parts, even with shipping. Definitely use the install grease. The paper says that the bushings last longer with the grease.

One thing nobody considers...is the rubber bushings will outlast the Urethane ones...

I replaced every rubber bushing in a street legal race car I built 13 years ago with urethane bushings (including the motor mounts)....it handled phenomenally well for a long time....things degraded to at one point I was in pain driving the car....in putting softer springs on it I discovered the bushings had worn out...a significant ammount...and had to replace ALL of them again.

Decide what you are after....if you like the stock ride...use rubber bushings...if you plan on doing all of them to improve handling....they will at the cost of harshness...and the knowledge you will be replacing them a number of years down the road.

Good points to consider. Thank you. I wonder if the grease recommended at installation helps with that to any large degree. I know over time, the grease will tend to get washed out.

The frame mounts can be made greasable, if you can not find them pre-made that way. The links just need to be considered wear items. The bushings that I presume Smoothy refers to include control arm bushings, which require much more labor to install.

Yes.....all of them..trailing arms...control arms...the works....they all wear....figure MAYBE 50K miles before they are shot.., even the urethane motor mounts wore out.

And it wasn't a heavy vehicle....only 2,100 lbs curb weight.

You HAVE to use the silicone grease during intallation or they won't fit...they are all usually press fit....some you can press by hand...some require a hydraulic press depending on what you are replacing.

On my application....making them greasable wasn't an option. And taking them appart to regrease them wasn't either.

Robin, Your views on this topic is appreciable. But I think the polyurethane bushings is necessary as it provide the pecific performance enhancement.