bignatesan

Does anyone know why some vendors (NPD) recommend rubber strut rod bushings over the polyurethane ones? I just bought an "Ultra Suspension Kit" from Mustang Depot with Maier racing control arms, roller perches and some other nice upgrades to compliment the Shelby Drop and disc upgrade I am doing at the same time. I would hate to create some annnoying vibration, squeak or thump by using poly instead of rubber on the Strut rods. Thanks.

Nate

Brandontyler65

well i went to the local perf shop and they seem knowledgable bout this stuff and they told me to be careful with what poly-u bushing you get they told me to only use rubber or energy sus poly bushing cause they flex somewhat and some poly's don't flex at all and that where you get into trouble

dawtips

Apparently, poly bushings could cause the strut rod to break. I've been running my struts w/ poly bushings for the last 2 months with no problems.

baddog671

Ive always heard they are too stiff and cuase squeking, but are better for handling than rubber. And rubber is good for cruisers and have more give.

They also make a type that is like half and half. Midoline comes to mind, but Im not sure..

Soaring

For all your front suspension upgrades, polyeurethane bushings are superior to rubber. For more precise handling and firmer control on your Mustang, installing polyurethane bushings can make an enormous difference because they help to maintain the right alignment of caster, camber and toe, even on rough or uneven pavement.
Another advantage of polyurethane bushings is that they're virtually impervious to oil and other road contaminants. These units will not crush down or wear out like rubber bushings, and are designed to be free-floating, rotating 360 degrees, so the suspension can articulate fully without binding. In contrast, rubber bushings are often bonded to a metal shell and sleeve, and function with a twisting action that, when pushed to its limit, binds up instead of rotating freely like urethane units. Rubber bushings can even induce wheel hop from the spring-like action of the rubber twisting back and forth.

baddog671

good answer!

Lumbergh

I second (or third) Soarings response. I do not believe that he specifically stated it, but poly bushings will last much longer, as well.

rmodel65

yes they are stiffer and thats the problem the stock strut rods are beefy enough. they can cause strut rod failure[:'(] dont use the poly bushing on a street car! not good when a wheel wraps under the car

Soaring

So, you are saying that poly bushings in the strut rod will cause strut rod failure? Is that what you are saying? Worn strut rod/radius rod/tension control rod bushings will cause excessive caster change and make the car want to change lanes when the brakes are applied. Poly-urethane strut rod bushings, with their increased density will decrease castor change. Poly urethane will not degrade like rubber, so they will last much longer than rubber. I once purchased a nice '65 Mustang with drum brakes from an owner who was frustrated with the car, because he could not make it stop in a straight line. When I went to look at the car, he told me of the problem with the brakes. He told me how he had replaced all the brake hardware, backing plates, shoes and the drums. He adjusted the wheel bearings properly, and it still wanted to pull to the left. I offered to tell him how to fix the problem. He was so upset he said, "you buy the car and you fix it. I'm through working on this turd". I purchased the car for a terrific price. Took it to my garage at home. Replaced the strut rod bushings with E.S. #4-7111-G. Drove the car and slammed on the brakes. The car came to a stop in a perfect straight line. He was right, he did a great brake job. But the brakes were not the problem. It was the strut rod bushings all the time. If you notice tire wear on the inside of the tread, you should suspect the control arm bushings.
Poly-urethane bushings will last longer than rubber and the increased density of Energy Suspension Hyper-Flex poly-urethane bushings, will greatly decrease the possibility of camber and caster change.
When you consider what your rubber suspension bushings are designed to do, insulate moving metal suspension components from each other, they do a good job. But there are trade offs. Hi-performance Poly-urethane bushings, are more like a bearing, that allow smooth movement of the suspension component(usually just up & down) without the unwanted twisting, side to side, bushing crush and rapid deterioration, that is inevitable with rubber bushings.

bignatesan

Thanks for all of the input guys. I talked with NPD and Mustang Depot reps today and got completely opposite advice from each. The NPD rep. told me that the poly bushings can break the strut rod right at the threads from regular street use. He said the forced place on the strut rod doing things like going in and out of driveways; potholes and other routine events can break the strut rod at the threads. He said it happened to him personally. The Mustang Depot rep said no way that a poly bushing would cause a strut rod to break. To be safe I am going to go with a reinforced rubber bushing. If something bad can happen, it will happen to me so I ain't rolling those dice.

I would hope if there was such a real possibility of breaking the stock strut rod, the bushing manufacturers would cease making them for anything other than track use. Again, thanks for all the input.

Nate