View Full Version : Rubber verses polyurethane bushings

04-23-2006, 10:51 AM
I know my car is getting to the point where I am going to need to replace the rubber bushings throughout. My questions is should I replace them with rubber or go to the polyurethane bushings? I know the poly bushings will last longer, but is performance sacrificed in any way? Since the poly bushings are stiffer, does this casue other parts to wear prematurely instead? Any suggestions would greatly be appreciated.

04-23-2006, 11:17 AM
I would suggest poly. There was a thread a week or two ago that you can refer to for more information.

04-23-2006, 11:59 AM

I went with NYLATRON SUSPENSION BUSHINGS from Goodparts. Infact, I did all of his recomended upgrades which radically changed how my TR handles for the better. I would think the only reason to not go with Nylatron would be if your driving takes you on a lot of poorly maintained roads in which case the ride could be too stiff.

04-23-2006, 12:59 PM
The rubber bushings are still holding with about 85k miles and 30+ years of aging. Alignment does not need adjustment after being aligned in the mid '80's. No groans or squeaks coming from the suspension.

The point, how long is long? If you can get OEM parts, rubber will be fine and last a very long time.

If you race, get the non-shock absorbing polyurethane. If you need urethane bushings for precise control, you will no doubt have to stiffen the chassis or the effort will be wasted from a steering control standpoint. No argument, if you need all out steering performance, get the poly's.

If you are not racing, consider your passenger if you have one that rides with you (nothing like girl to make a sports car look good) The feel of "no sway", precise steering makes many people nauseated (DRIVER EXCLUDED.) This is not fact, just opinion.

04-23-2006, 01:03 PM
I second the vote for Nylatron. It's better than the poly bushings without the squeak... IMO, the increased ride harshness is minimal at best, and it feels "modern car" tight.

04-23-2006, 02:45 PM
Speaking of Goodparts, am i the only one who has a prefilled shopping cart there? /ubbthreads/images/graemlins/confused.gif When I try to add something to the cart, it shows $100,317.00 worth of parts already added - at least one of everything, and many of some things.

04-23-2006, 02:54 PM
I don't know why it does that. I ordered the Polished SS Radiator shrouds last week and when I went to check out it was over $100K! I just selected all and deleted everything then reentered my shrouds and all was well.

04-24-2006, 02:46 PM
Rubber bushings operate in a different way than polyurethane. For IRS trailing arms, rubber bushings take up the motion by "twisting" between the outer circumference (against the trailing arm) and the inner steel sleeve to which the rubber is bonded. The poly bushings don't twist, they rotate around the inner sleeve. That's why they often squeak. The rubber bushes are also more pliable and allow axial deflection with regard to the sleeve and bolt. When drive is taken up, some of the shock is absorbed by the rubber bushings -- by design. With poly, more of that shock is transmitted to other components. Google "bushings" and "Land Rover" and you will see a lot of comments from people who have gone poly but then reverted to rubber, especially those who go off road. I've seen a number of experiences related where the lack of shock absorpion by poly bushings has led to oval elongation of the holes through which pass the bush securing bolts. Also consider that Triumph relied on the pliability of the rubber bushings in the design, because it is more forgiving of slight errors in alignment.

The rubber bushes on my TR4A are old but still serviceable. The ride is excellent and smooth, and I for one would not change. If you change to poly, you will undoubtedly perceive a "tighter" ride, and so will the chassis. Many have switched to poly because the pitch sounds so good...and then come back to rubber.

04-24-2006, 04:24 PM
I'm glad I'm not the only guy with 30+ year old rubber bushings underneath! /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/blush.gif Every time I'm under the car, I groan to myself about them. I'm actually planning on having the shop replace them all (front and back) in the next couple of weeks. I'm going to go with rubber, for exactly the reasons outlined by 4anot4 outlines above. All that flex and energy has to go somewhere! /ubbthreads/images/graemlins/thumbsup.gif

04-24-2006, 11:58 PM
If you like to hustle IRS TR's through corners and not have the rear end of the vehicle start twitching, then switching to polys in the rear trailing arms is a must. Even if they are the only ones that you switch over. They will at least allow the rear wheels to stay pointed in the same direction through a corner. The rubber trailing arm bushings allow way to much flex of the trailing arms and can cause the rear end to become very unsettled. Polys here won't really effect the ride very much but will make the largest change in handling where bushings are concerned. There are also roller bearing conversions for the trailing arms if poly isn't enough.

Mixing poly and rubber can give you a bit of both worlds. Slightly improved handling with slighty decreased ride quality. But its still you who will have to decide where and when to compromise.

If your not sure of what I mean by the rear end becoming unsettled with the rubber bushings, then your not going through the corners fast enough to worry about it. /ubbthreads/images/graemlins/devilgrin.gif /ubbthreads/images/graemlins/driving.gif


04-25-2006, 09:58 PM
my vote- rubber Arms and link bushings, poly sway bar bushings with an upgraded sway bar

04-25-2006, 11:05 PM
Your decision should be based on the type of driving you plan to do. If you want to do a little autocross or spirited country road driving and handling is a priority, I'd select nylatron.
If you plan to drive the car often, and like your driving spirited; don't plan to autocross; and want a fairly maintenance free front end, use urethane. If you thoroughly clean your surfaces and use a dry lubricant that is suggested for use with urethane bushings, you should have no squeaking.
If you don't plan to drive your car very often, and use it for cruising on the weekend with the wife(since her Bugeye is still on blocks)in nonspirited driving, rubber should suffice. Don't expect rubber to last long. Reproduction bushings don't hold a candle to the originals.
My preference? I went Nylatron and have no thoughts of changing.

04-26-2006, 01:33 AM
Following up on DougF, I will add that if you are a real Triumph driver and use your car daily for everyday stuff, rubber bushings are far superior. There is a reason why almost all current production vehicles use rubber bushings.

04-26-2006, 10:31 AM
Finding rubber bushings that are worth installing is the problem. The rubber upper a-arm bushings I used were splitting after only two years. I could tell the rubber wasn't like OEM rubber, but I wanted to use rubber, I will be replacing the rubber with the prothane bushings soon.

04-26-2006, 02:06 PM
The problem of excessively hard poly bushings has been addressed by Polybush, a UK company. I think that they were the first company to offer poly bushes for Triumphs. They have three lines of bushes: red(hard), blue(soft) and orange(in between). The blue ones are supposed to have the same softness as original rubber. If you are going to go poly, they may be worth a look. Website is www.polybush.co.uk (https://www.polybush.co.uk) -- not sure of they have a US distributor, but they seem to have a good reputation.

Given that so many modern cars use rubber bushings, I should think that there must be better quality OEM bushings from another make that are a direct fit. Then we could avoid the apparent lack of quality of the bushes stocked by the big three.

04-26-2006, 07:47 PM
The only thing better that poly bushings is colored ones. I have not seen any on a TR6 but they do look good on Camaro's and Vettes.